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Closing the Loop (Full Film) - English with Multi-Language Subtitles

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Why Farming Is Broken (And Always Has Been)

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Why Farmers Can’t Legally Replant Their Own Seeds

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The UN's 1952 Refugee Convention, which clarifies the rights of refugees and the legal obligations of the signing countries to protect them, does not apply here in Hong Kong.

In Hong Kong, refugees can seek "non-refoulement", which would protect them from being returned to a country where they would face torture, cruel, inhuman or degrading treatment or punishment and other irreparable harm.

However, even with a successful protection claim, they cannot become Hong Kong residents and they cannot stay here long term.

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The UN's 1952 Refugee Convention, which clarifies the rights of refugees and the legal obligations of the signing countries to protect them, does not apply here in Hong Kong. In Hong Kong, refugees can seek "non-refoulement", which would protect them from being returned to a country where they would face torture, cruel, inhuman or degrading treatment or punishment and other irreparable harm.

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The Effect of Listening to Pachelbel’s Canon in D Major on... : Taiwanese Journal of Psychiatry

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al practice. In this pilot study, we intended to investigate the effectiveness of using Pachelbel’s Canon in D major as a music therapy to reduce anxiety levels in patients receiving pulmonary rehabilitation for chronic obstructive pulmonary disease (COPD). Methods: Fifty patients with COPD receiving pulmonary rehabilitation from a hospital in New Taipei City. They were randomly assigned in blocks for two groups, control group in a quiet environment, and experimental group listened to the Pachelbel’s canon in D major. Results: A significant difference in the anxiety score during pulmonary rehabilitation between the experimental group and the control group was found through an independent sample t-test in this study (p < 0.05). Conclusion: Listening to the music of Pachelbel’s canon in D Major decreased the anxiety level of patients with COPD during pulmonary rehabilitation.…

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Music | Art Form, Styles, Rhythm, & History

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Music, art concerned with combining vocal or instrumental sounds for beauty of form or emotional expression, usually according to cultural standards of rhythm, melody, and, in most Western music, harmony. Learn about the history of music and about theories of musical meaning since the 19th century.

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Beethoven's autographic sketch for his Piano Sonata No. 28, Movement IV, Geschwind, doch nicht zu sehr und mit Entschlossenheit (Allegro). He completed the piece in 1816.

Art music (alternatively called classical music, cultivated music, serious music, and canonic music) is music considered to be of high phonoaesthetic value. It typically implies advanced structural and theoretical considerations or a written musical tradition. In this context, the terms "serious" or "cultivated" are frequently used to present a contrast with ordinary, everyday music (i.e. popular and folk music, also called " vernacular music"). Many cultures have art music traditions; in the Western world, the term typically refers to Western classical music.

In Western literature, "Art music" is mostly used to refer to music descending from the tradition of Western classical music. Musicologist Philip Tagg refers to the elitism associated with art music as one of an "axiomatic triangle consisting of 'folk', 'art' and 'popular' musics". He explains that each of these three is distinguishable from the others according to certain criteria. According to Bruno Nettl, "Western classical music" may also be synonymous with "art music", "canonic music", "cultivated music", "serious music", as well as the more flippantly used "real music" and "normal music". Musician Catherine Schmidt-Jones defines art music as "a music which requires significantly more work by the listener to fully appreciate than is typical of popular music". In her view, "[t]his can include the more challenging types of jazz and rock music, as well as Classical".

The term "art music" refers primarily to classical traditions (including contemporary as well as historical classical music forms) that focus on formal styles, invite technical and detailed deconstruction and criticism, and demand focused attention from the listener. In strict western practice, art music is considered primarily a written musical tradition, preserved in some form of music notation, as opposed to being transmitted orally, by rote, or in recordings (like popular and traditional music).

There have been continual attempts throughout the history of popular music to make a claim for itself as art rather than as popular culture, and a number of music styles that were previously understood as "popular music" have since been categorized in the art or classical category. According to the academic Tim Wall, the most significant example of the struggle between Tin Pan Alley, African-American, vernacular, and art discourses was in jazz. As early as the 1930s, artists attempted to cultivate ideas of "symphonic jazz", taking it away from its perceived vernacular and black American roots. Following these developments, histories of popular music tend to marginalize jazz, partly because the reformulation of jazz in the art discourse has been so successful that many (as of 2013) would not consider it a form of popular music.

At the beginning of the 20th century, art music was divided into "serious music" and " light music". During the second half of the century, there was a large-scale trend in American culture toward blurring the boundaries between art and pop music. Beginning in 1966, the degree of social and artistic dialogue among rock musicians dramatically accelerated for bands who fused elements of composed music with the oral musical traditions of rock. During the late 1960s and 1970s, progressive rock bands represented a form of crossover music that combined rock with high art musical forms either through quotation, allusion, or imitation. Progressive music may be equated with explicit references to aspects of art music, sometimes resulting in the reification of rock as art music.

While progressive rock is often cited for its merging of high culture and low culture, few artists incorporated literal classical themes in their work to any great degree, as author Kevin Holm-Hudson explains: "sometimes progressive rock fails to integrate classical sources ... [it] moves continuously between explicit and implicit references to genres and strategies derived not only from European art music, but other cultural domains (such as East Indian, Celtic, folk, and African) and hence involves a continuous aesthetic movement between formalism and eclecticism".

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Art music (alternatively called classical music, cultivated music, serious music, and canonic music) is music considered to be of high phonoaesthetic value. It typically implies advanced structural and theoretical considerations or a written musical tradition. In this context, the terms "serious" or "cultivated" are frequently used to present a contrast with ordinary, everyday music (i.e.

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hong kong sports institute - identify sports talents

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Video Gallery - News & Publications - Hong Kong Sports Institute

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Hong Kong Sports Institute, 25 Yuen Wo Road, Sha Tin, N.T., Hong Kong

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Mental Health Benefits of Playing Sports | Mental Health in Sports

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Joining a sports team can bring mental and physical health benefits. Sports can decrease the chances of anxiety or other mental health issues. Learn more.

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Every sport in the world

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November has been one of the year’s quietest months in terms of major international tournaments, with only 1,610 GSN points awarded, but four sports that were recently add…

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All the latest content about Animals from the BBC.

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The Gonzaga University sports team was departing Los Angeles when the incident occurred.

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Why Are Youth Sports Programs Important?

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Youth sports are fun and promote physical and mental health for kids.

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Individual Sessions Multiple Sessions Training squad running and triathlon (For those wanting more than 2 sessions per week) YDP squad running and triathlon (For those who qualify for National or…

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People are converting old coolers into shelters for stray cats! #shorts

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WHO fact sheet on mental health covering risks and protective factors, promotion and prevention, care and treatment, and WHO’s work in this area.

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What is Monoculture and How Can it Affect Our Soil?

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Monoculture or monocropping is the agricultural practice of growing a single crop year after year on the same land, in the absence of rotation through other crops or growing multiple crops on the same land, which is known as polyculture. Polyculture is much healthier for the soil as it feeds the huge diversity of insects, bugs and microbes that are responsible for keeping the soil healthy. Plant diversity can also work as a natural pesticide. Think of it like your stomach - it works much more effectively when there is a multitude of balanced good bacteria working together. Monocropping strips this away. While growing one type of crop has no doubt simplified farming practices and aided our ability to increase yields to feed our growing population, there are also a number of drawbacks. Removing multiple plant species in favour of a single crop eventually depletes the soil of its biodiversity and also increases the amount of opportunistic pests that feed on the crops. As the soil becomes exhausted of its nutrients, the need for more chemical inputs to ensure crop growth can take place as well as removal of pests increases. As we know, these synthetic fertilisers and pesticides negatively affect the soil even more which has consequences for our environment and quality of food. Poor soil health will lead to food that is less nutrient dense and affect the ability of the soil to draw down and store carbon from the atmosphere. Meaning that the soil’s ability to help reverse climate change is negatively affected. Not all monoculture is bad and there is a place for it in farming if done correctly. However, mass scale monoculture that is common in soy, wheat, corn, avocado, palm and banana production that extends for miles and miles is an issue and will affect arable top soil over time. Another alarming element to mass scale monoculture is that a large amount of the corn, soy, and wheat grown in monocropping is then fed to animals in intensive farming practices. Some say even up to 40% of grain production goes to grain fed animals. This is a great reason to avoid grain fed meats if you are environmentally conscious.
According scientists, at current rates of soil destruction (through decarbonisation, erosion, intensive farming, desertification, chemical pollution), within 50 years we will not only suffer serious damage to public health due to a qualitatively degraded food supply from diminished nutrition and loss of important trace minerals, but we will literally no longer have enough arable topsoil to feed ourselves. Without protecting and regenerating the soil on our 4 billion acres of cultivated farmland, 8 billion acres of pastureland, and 10 billion acres of forest land, it will be impossible to feed the world, keep global warming below 2 degrees Celsius, or halt the loss of biodiversity.

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By Katie Garrity

May. 19 2020, Updated 10:50 a.m. ET

There is a lot of buzz around monoculture and monocropping. Many farmers have taken to this method of farming their crops as, for them, there are some benefits. However, when it comes to the environment, the benefits are few.

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The effects of monocropping can be extremely detrimental to the environment. For farmers and gardeners, planting monoculture crops may seem an easy method to get the job done, but in reality, the adverse effects of monocropping can lead to a number of issues down the road.

Monocropping has many disadvantages to the environment.

Now with each season of monocropping, the surrounding land is even more reliant on the pesticides to fight off predators which in return puts more chemicals into the system. Another factor to consider when arguing that monocropping is problematic is how limiting farms to just one crop does not provide the diversity needed in our diets or to our ecosystem. In fact, according to Healthy Planet, 75 percent of the world's crop varieties have been lost over the last century.

Manu Saunders, a post-doctoral Research Fellow in Ecology points out, maintaining biodiversity in plantations supports important ecosystem services that can increase yields, such as unmanaged pollination, biological control, and waste disposal services.

To fight against monocropping, shop local and buy organic.

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Here's Everything You Need to Know About Monocropping (And How It's Hurting the Environment)

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By Katie Garrity May. 19 2020, Updated 10:50 a.m. ET There is a lot of buzz around monoculture and monocropping. Many farmers have taken to this method of farming their crops as, for them, there are some benefits. However, when it comes to the environment, the benefits are few.

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Teen Sports and Mental Health: 10 Mental Benefits of Sports

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Teen sports can have a major impact on quality of life. Physical activity has significant benefits for teen mental health.

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What is mental health?

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Mental health: Definition, common disorders, early signs, and more

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Mental health refers to cognitive, behavioral, and emotional well-being. We define mental health, explain different disorders, and assess potential treatments.

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National Institute of Mental Health (NIMH)

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Overview

Mental health includes emotional, psychological, and social well-being. It affects how we think, feel, act, make choices, and relate to others. Mental health is more than the absence of a mental illness-it's essential to your overall health and quality of life. Self-care can play a role in maintaining your mental health and help support your treatment and recovery if you have a mental illness.

About Self-Care

Self-care means taking the time to do things that help you live well and improve both your physical health and mental health. When it comes to your mental health, self-care can help you manage stress, lower your risk of illness, and increase your energy. Even small acts of self-care in your daily life can have a big impact.

Here are some tips to help you get started with self-care:

Get regular exercise. Just 30 minutes of walking every day can help boost your mood and improve your health. Small amounts of exercise add up, so don't be discouraged if you can't do 30 minutes at one time.

Eat healthy, regular meals and stay hydrated. A balanced diet and plenty of water can improve your energy and focus throughout the day. Also, limit caffeinated beverages such as soft drinks or coffee.

Make sleep a priority. Stick to a schedule, and make sure you're getting enough sleep. Blue light from devices and screens can make it harder to fall asleep, so reduce blue light exposure from your phone or computer before bedtime.

Try a relaxing activity. Explore relaxation or wellness programs or apps, which may incorporate meditation, muscle relaxation, or breathing exercises. Schedule regular times for these and other healthy activities you enjoy such as journaling.

Set goals and priorities. Decide what must get done now and what can wait. Learn to say "no" to new tasks if you start to feel like you're taking on too much. Try to be mindful of what you have accomplished at the end of the day, not what you have been unable to do.

Practice gratitude. Remind yourself daily of things you are grateful for. Be specific. Write them down at night, or replay them in your mind.

Focus on positivity. Identify and challenge your negative and unhelpful thoughts.

Stay connected. Reach out to your friends or family members who can provide emotional support and practical help.

Self-care looks different for everyone, and it is important to find what you need and enjoy. It may take trial and error to discover what works best for you. In addition, although self-care is not a cure for mental illnesses, understanding what causes or triggers your mild symptoms and what coping techniques work for you can help manage your mental health.

For other ideas for healthy practices for your mind, body, surroundings, and relationships, see the National Institutes of Health (NIH) Wellness Toolkits .

When to Seek Professional Help

Seek professional help if you are experiencing severe or distressing symptoms that have lasted 2 weeks or more, such as:

Difficulty sleeping

Appetite changes that result in unwanted weight changes

Struggling to get out of bed in the morning because of mood

Difficulty concentrating

Loss of interest in things you usually find enjoyable

Inability to perform usual daily functions and responsibilities

Don't wait until your symptoms are overwhelming. Talk about your concerns with your primary care provider, who can refer you to a mental health professional if needed. If you don't know where to start, read the National Institute of Mental Health (NIMH) Tips for Talking With a Health Care Provider About Your Mental Health. Learn more about how to get help or find a provider on the NIMH's Help for Mental Illnesses webpage.

What to Do in a Crisis

If you or someone you know is struggling or having thoughts of suicide, call or text the 988 Suicide & Crisis Lifeline at 988 or chat at 988lifeline.org . This service is confidential, free, and available 24 hours a day, 7 days a week. In life-threatening situations, call 911.

For additional information about suicide prevention, please see NIMH's Suicide Prevention webpage.

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Federal Resources

Other Resources

Note: This list of non-federal resources is provided for informational purposes only. It is not comprehensive and does not constitute an endorsement by NIMH, NIH, the U.S. Department of Health and Human Services, or the U.S. government.

Last Reviewed: December 2022

Unless otherwise specified, the information on our website and in our publications is in the public domain and may be reused or copied without permission. However, you may not reuse or copy images. Please cite the National Institute of Mental Health as the source. Read our copyright policy to learn more about our guidelines for reusing NIMH content.

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Mental health includes emotional, psychological, and social well-being. It affects how we think, feel, act, make choices, and relate to others.

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Summary

Monocropping - the growing of a single crop over and over on the same piece of land - was invented to increase the food supply and combat hunger. Unfortunately, its unintended consequences threaten greater global food insecurity and worsen climate change. In this article, we'll explore monocropping pros and cons (spoiler alert: more cons than pros) and look at alternative growing methods that you can support.

I'll begin with a simple definition: monocropping is planting and growing one type of plant in the same place, year after year. It's the type of planting that occurs under a type of agriculture called monoculture. If you've ever driven through large agricultural fields completely filled with - say, corn - as far as the eye can see, you're in monoculture country. Monoculture is an agricultural system that involves the planting of a single crop, over and over.

That cornfield was a cornfield last year, and the year before, and it will be a cornfield next year, and into the foreseeable future. It's a monoculture because corn holds a monopoly on that field - no other crops allowed. Because monocultures typically exist at large scale, and can accommodate both conventional and organic farming, the vast majority of the agricultural yield in industrialized countries comes from monocultures.

The question is, why? It's obvious that nature doesn't monocrop. You'll never see an area untouched by humans that is completely dominated by a single species of plant. Nature abhors not just a vacuum, but sameness. Biodiversity is the signature of a natural system.

To understand the reasons behind the global shift to monocultures, and why the agricultural sector has embraced it so wholeheartedly, we have to look at the Green Revolution of the 1960s, and the hopes of the scientists, policy makers, and farmers who were struggling with the twin scourges of poverty and starvation.

How Did Monocropping Come About?

Monocropping was a cornerstone of a series of initiatives intended to address hunger throughout the world by increasing agricultural production. The plan was to develop a wide array of effective pesticides and herbicides, create and teach farmers to use new synthetic fertilizers, breed new and improved "high-yield varieties" (HYVs) of calorically dense crops, and mechanize farm equipment.

The thing that was going to make all of these innovations work was a shift in how agricultural land was used. Traditionally, subsistence farmers and smallholders planted a variety of crops, from grains to pulses to nuts to vegetables to fruits to herbs. But the new technologies and systems of mass production were only going to work, the thinking went, at a large scale.

The big machines were expensive and were designed to handle a specific crop. You don't harvest wheat with the same equipment you use to harvest soybeans. Each crop required a custom application of biocides and fertilizers, as well. In order to get the most out of these technological advances, farming had to change from the workshop model to the factory model.

To replace biodiverse gardens and farms with industrial-sized agriculture, vast swaths of arable land were converted into single-crop use. That way, the farmers could use their new equipment and synthetic chemicals on new HYVs that were bred to tolerate the toxins and make the most of the fertilizers.

As a result, farms around the world increased in size, on average doubling the number of acres under cultivation, in order to produce more food with less labor. With a single farmer able to produce more food, the number of farmers and farm laborers decreased, as human inputs were replaced by machines and by chemicals, often delivered from the air. Over time, more and more farms relied solely on these high-yielding crops, in the form of monocropping, to increase yields and profits.

This logic led to vigorous efforts to bioengineer HYVs to produce heartier, faster-growing, and more resilient crops that define monoculture, rather than relying on trial and error or "natural" breeding.

Now, let's look at some of the monoculture advantages and disadvantages for farmers.

Economic Advantages of Monocropping for Farmers

At first, farmers thought they were on to a good thing. They could now produce more food, and opted to cultivate the one crop that had the greatest profit potential for their soil and climate.

Another monocropping benefit to farmers was the perceived simplicity that saved them time and money, at least in the short-term. Focusing solely on a single crop meant the costs for seeds, equipment, fertilizer, and so on, remained relatively consistent over time, and farmers didn't have to keep looking for new suppliers.

GMOs and Monocropping

As bioengineered (BE) crops (formerly known as GMOs), such as Roundup Ready corn, soybeans, and sugar beets hit the market, the pairing process got even simpler. The farmer had a standing order of glyphosate (one of the active ingredients in Bayer's - formerly Monsanto's - weed killer Roundup) that accompanied every purchase of BE seeds.

Harvesting also got much simpler, as a single machine designed specifically for corn, wheat, or beets could do the work of hundreds of human laborers.

The Emergence of Factory Farms

And last, but certainly not least among the perceived benefits of monocultures, monocrops became inextricably interlinked with a massive expansion in factory farming (or what the industry calls Concentrated Animal Feeding Operations, or CAFOs). Today, much of the world's corn and soy are fed to livestock, not to humans. And CAFO-raised cows, pigs, and chickens represent an almost limitless market for these crops.

The overall result of monocropping, for the first couple of decades, appeared to be mostly positive - at least in terms of the goals of bringing the world more and cheaper calories and increasing the economic security of the farmers who provided it. But all those perceived savings came with hidden costs that added up over time.

Monocultures (and the Green Revolution in general) were promoted to increase the global food supply. While that's happened, there have been several attendant negative consequences. (I'd say "unforeseen consequences" but I'm not sure that's true. It didn't take psychic powers to imagine the effects of a dietary pattern made up largely from factory farmed animal products and processed corn, soy, wheat, and palm oil replacing traditional diets.)

Economic Disadvantages of Monocropping for Farmers

The fundamental issue with monocropping is the "all the eggs in one basket" problem. Crop failure is an inevitable part of farming. For myriad reasons that farmers can't control (most of them falling under the categories of weather, pests, and disease), not all plants thrive and produce a bountiful and profitable harvest every single year.

In a biodiverse ecosystem, a threat to one crop may not be a threat to others. An infestation of stem borers can destroy summer squash but may leave eggplant untouched. An unexpected hail may crush corn and not bother beets.

But when fields contain just one crop, from genetically identical stock, every single plant is equally vulnerable to threat. A pest population can jump easily from one plant to another, especially when there are no other species of plants in between and when crops are planted close together for efficiency.

Monocropping Through History

To see the devastating results when a monocrop comes under threat, check out the history of the Irish potato famine of the 1840s, in which a single genetic variant of potatoes was wiped out by a water mold. The Irish people's dependence on that variant for the majority of their calories meant that over a million people starved to death (an eighth of the entire Irish population), and millions more left the country as refugees.

The history books offer at least one more example of the dangers of relying on monocrops. The world's most popular banana up until the 1950s was a variant known as Gros Michel. You can't find a single one anymore, as the world's supply was knocked out by a fungus that caused Panama disease, which led to banana wilt.

In response, banana producers turned to a less tasty variety, the Cavendish, which is the fruit we know today. Unfortunately, the banana industry didn't learn its lesson, as the Cavendish comprises 99% of the world's banana production, and is now under attack from a new variant of Panama disease called TR4. Dan Koeppel, author of Banana: The Fate of the Fruit That Changed the World , predicted in an NPR interview that the Cavendish could become extinct in the next 10-30 years.

A Trap for Farmers

Monoculture farming can become a trap for the farmers, who often have no choice but to keep purchasing the same seeds and biocides from their agribusiness vendors. Since the seed and agrochemical market was consolidated through mergers and acquisitions into just four main global players, these firms can exert monopolistic power over the farmers who depend on them for seeds and chemical inputs.

The result is increased costs and eroded profit margins for farmers. For example, the price of corn seed rose from under $27 per planted acre of seed to over $90 from 1990 to 2019, far outstripping the rate of inflation. And because monocrop corn farmers have invested so heavily in machinery and infrastructure for growing and harvesting corn, they can't easily exercise free choice and move to another crop or growing model.

The consolidation of seed and supply companies into just a few global companies isn't the end of the "bigger is better" story. Farms themselves are growing larger, by buying up competitors' land or squeezing family farmers out of business. Bigger farms that buy at large scale are rewarded with favorable pricing, which makes it much harder for smaller farms to compete fairly in the marketplace.

Many farmers are forced to buy Bayer seeds and pesticides even if they don't want to. When neighboring farms spray so much of the weed killer dicamba that the air turns hazy, those toxic clouds can waft for two to three miles, killing any soybean plants that aren't bioengineered with dicamba-resistant genes - which is to say, any soybeans not made by Bayer.

Government Subsidies and Monocultures

Not coincidentally, crops produced in a monoculture system are often the same ones that are subsidized by the government (at taxpayer expense, of course). Subsidization is generally delivered in the form of insurance for farmers, guaranteeing that they can sell their crop above a certain price, no matter how low the actual market value for that crop falls. The primary subsidized crops in the US are corn, soy, wheat, and rice.

One out of every five dollars earned by US farmers comes directly from government payouts. These subsidies now buffer farmers not just from the threat of a bad harvest or market crash, but from any marketplace fluctuation. Without subsidies, it would be economic insanity to grow just one or two crops. If the price of corn dropped sufficiently, a farm that relied entirely or mostly on corn for its income could get completely wiped out in a single season.

Finally, subsidies tend to favor large farms, as government payouts often disproportionately go to the biggest producers.

Monoculture's Impacts on the Food Supply & Food Insecurity

At a large scale, monocropping means that poor countries must compete with wealthy ones, in the open market, for a slice of the same global food supply. While traditionally a poor country might be able to grow its own food more cheaply, since wages were also lower, now the entire world bids for commodity crops, which places lower-income nations at a disadvantage.

Because the Green Revolution, in general, and monocropping, in particular, prioritizes efficiency over resilience, there's very little slack in the system when anything goes wrong. And in agriculture, things often do go wrong. Shocks and uncertainties are part of the web of life, which is why nature builds redundancy and diversity into its design.

When humans decimate that diversity through monocropping, any event that leads to a diminished harvest has ripple effects, such as increasing food prices and bringing about greater food insecurity.

The COVID-19 Pandemic and Monocropping

We've seen this play out during the COVID-19 pandemic. The World Bank, a long-time supporter of industrialized agriculture at scale, has admitted that even before the pandemic, monocropped agriculture was collapsing. Here's a remarkable sentence from an article on the World Bank's website: "Even before COVID-19 reduced incomes and disrupted supply chains, chronic and acute hunger were on the rise due to various factors, including conflict, socio-economic conditions, natural hazards, climate change and pests."

As the pandemic unfolded, the article continues, these already scarce resources became even more expensive, with the Agricultural Commodity Price Index increasing 25% from January 2021 to January 2022. Again, the global economically poor were getting priced out of access to food grown on their own lands, which replaced the diverse and healthful horticulture and subsistence practices that had fed their families for generations.

For example, monocropping has displaced regional staples, such as millet, sorghum, and cassava, all culturally and nutritionally important sources of calories throughout much of Africa, the Indian subcontinent, and South America. These foods have been part of traditional healthy diets for hundreds of years, and their displacement threatens global crop diversity.

Monoculture's Impacts on Human Health

Human health also suffers when factory-farmed animal products and processed grains and oils replace traditional whole foods in our diets. Monocultures of corn and palm oil can produce more calories - but far less nutrition - per acre than many other crops. In a world of cheap calories from fractionated foods, malnutrition now refers as much to micronutrient deficiencies as to starvation.

A 2021 research paper on the effects of monocropping on the health of the economically poor highlights the scope of the problem in its first sentence: "Approximately 2 billion people globally are affected by micronutrient deficiencies; much of which is attributed to consuming a monotonous diet of nutrient-deficient staple crops."

Researchers have also documented a relationship between the decrease in dietary diversity and a reduction in the diversity of the human microbiome, with accompanying health challenges. And once a particular strain of beneficial microbes goes extinct in a population, there's a risk that it will never return.

Monocropping also makes it harder for farmworkers to lead lives of dignity, freedom, and security. As pests become resistant to pesticides, and weeds gain resistance to herbicides, agricultural chemical manufacturers have engaged in an arms race, increasing both the quantity and toxicity of chemical applications. While there's some debate about how much exposure to these agents harms consumers, there's no doubt that farmworker exposure to biocides is extremely hazardous.

Monoculture's Impact on Children

Children of mothers who work in pesticide-contaminated fields experience more neurological issues, cognitive impairment, and autism. Girls who grow up exposed to pesticides are at greater risk of infertility and breast cancer.

And throughout the world, children involved in monocropped agriculture, such as on oil palm plantations, are being exploited. Globally, millions of children and adults are essentially enslaved by their agricultural employers.

Environmental Impacts of Monocropping

Humans aren't the only species being harmed by monocropping. The practice is making the planet more susceptible to the ravages of climate change by eroding the land's ability to retain soil and water.

A 2020 study published in the prestigious journal Nature reported that land used for agriculture or tree farms, which comprises 40% of all the non-ice-covered land on the planet, "... is less able to withstand fires, pests, and extreme weather events." And since monocropping farmers lack the agility to shift their planting strategies in the face of climate change, they're extremely vulnerable to these effects.

Pest and Weed Resistance

As we've seen, monocropping and pesticide use go hand in hand. But insects and weeds are rapidly developing resistance to the most widely used pesticides, which creates a vicious cycle - when bioengineered, pesticide-resistant crops fail, agribusiness has doubled down on the strategy by unleashing an "arms war" of increased and more diverse pesticide deployment.

This creates two additional problems. First, since the costs of losing the battle to a pest or pathogen can mean economic disaster for growers and consumers, there's little appetite to risk alternative approaches to pest management that don't involve all-out chemical warfare. Second, climate change means that new pests can now thrive in areas where they until recently had never been seen.

Effect on Pollinators

I'm sorry to say this, but it gets worse. According to a 2019 report by the United Nations' Food and Agriculture Organization (FAO), monocropping, and the pesticide use that accompanies it, now threatens not just plant diversity, but pollinator diversity as well. According to the FAO, over one million species of plants and animals are endangered, including many insect pollinators without whose hard work we would be in real trouble. Of the 20 fastest growing crops in the world, 16 require pollination from insects or other animals. And the danger is not evenly distributed - the most affected countries are the emerging and developing nations in Africa, Asia, and South America.

Disrupts Water Supply

Monocropping also compromises our precious water supply. Fertilizers add nitrates, nitrites, and phosphates to our drinking water, as well as to other bodies of water. Nutrients leach out of our food supply and into water - which not only don't benefit the ecology of rivers, lakes, and ponds but can harm them by creating the conditions for algal blooms that starve aquatic creatures of oxygen.

And impoverished monocropped soil is less able to absorb rainwater, leading to more flooding and more dependency on irrigation.

Decreased Soil Biodiversity

Fertilizers, pesticides, and factory farm waste also harm the ability of soil to sustain life. Monocrops keep adding the same things and depleting the same things, leading to less biodiverse, resilient, and mineral-rich soil (and more dependence on external inputs such as chemical fertilizers).

Monocropping reduces organic matter in soil and can cause significant erosion. This decreases the diversity and abundance of bacterial communities in soil, which in turn undermines plant health and ultimately the health of the humans who eat the plants.

Sustainable Alternatives to Monocultures

As scary and sad as all this is, there's some good news that's also part of the story - we know how to grow food in ways that heal rather than harm the earth and ourselves.

Regenerative Agriculture

What's known as regenerative agriculture, and millennia-old, indigenous growing ways, prioritize practices that mimic natural ecological processes and promote biodiversity. Shifting to regenerative agricultural processes is also one of the most powerful levers at our disposal to combat human-caused global climate chaos.

Regenerative farming focuses on the health of the soil as a top priority. Unlike monocropping, which sacrifices long-term soil health for the short-term production of marketable crops (did none of these scientists or policy makers encounter the story of "the Goose Who Laid the Golden Egg" as a child?), responsible land stewards treat the soil as their primary asset, which produces wealth in the form of food year after year.

Regenerative practices have been shown to enhance soil health, increase soil-based carbon stores (which is good for the climate as well as the plants growing in that soil), improve the physical structure of the soil so that it can hold more carbon, water, and oxygen, and boost soil biodiversity.

Intercrops, Cover Crops, and Polyculture

Other examples of sustainable growing include intercropping - planting more than one crop in a field - and polycultures, which means planting multiple crops together that all help each other grow better.

A well-known example of such a polyculture is the " 3 Sisters " of South and Central America: corn, beans, and squash. Planted together, all three do much better than any one on its own. The squash puts out big leaves that outcompete weeds, but only after the corn and beans have grown taller than the squash leaves. The corn provides a frame upon which the beans can climb. And the beans, like all legumes, fix nitrogen in the soil for the other two sisters. The result is healthier plants and higher yields without the need for so many (or any) chemical fertilizers and herbicides.

Another technique, planting cover crops on part of the land to serve as "green manure" for other crops, adds nutrients and reduces the need to import fertility from outside the farm.

Integrated Pest Management

A sophisticated method of dealing with insects that eat crops, integrated pest management (IMP) also mimics nature, which doesn't try to eliminate species entirely but keeps them in check through predation. Rather than killing life and reducing biodiversity, IMP takes the opposite approach, nurturing the presence of organisms that prey on the critters that prey on the crops.

Agroforestry

Nature, of course, doesn't grow food in rows, but produces its bounty in meadows, orchards, glens, jungles, and forests. All these ecosystems are characterized by robust biodiversity that's expressed in vertical layers, with roots, ground cover, shrubs, bushes, short trees, and tall trees all sharing the sun, soil, and rain to their collective benefit. Agroforestry is an approach to growing crops that mimics the design and function of a grove, with crops and trees interplanted.

While there is always more to learn, and there are many new breakthroughs to be had, this isn't entirely new science. Indigenous farmers have been refining these techniques for millennia, to protect their crops from extreme weather events, maximize the resources that can be harvested from a single location (legumes and lettuce and lumber, oh my!), increase soil fertility, and store carbon.

Indigenous farmers also save and treasure many varieties of each crop, which increases the odds that any disease that attacks a particular strain won't be able to destroy the entire crop. And the genetic variability also provides nutritional and usage variability, so the community can get far more from its arable land than a single crop would provide. This approach truly provides the farmers with land for life, rather than cash crops for a few seasons.

What Can You Do as a Consumer?

Given the urgency of our collective generational challenge - to produce food sustainably and ethically so that all may be fed - what can each of us do to participate in the shift from industrial monocropping to regenerative agriculture?

At a personal level, we can start by directing our hard-earned money towards foods that align with our values.

1. Eliminate Factory Farmed Meat and Dairy

A strategy with a particularly big impact is to steer clear of industrially produced animal products such as meat and dairy. That's because much of the monocropped and bioengineered corn and soy grown around the world goes to feed livestock.

2. Cut Down on Processed Foods

You can also say no to monocropping by reducing your purchases of processed foods, especially those made with palm oil, non-organic corn, and soy by-products. This isn't as simple as looking for "corn" or "soy" on a food label: corn by-products can hide behind words like maltodextrin, sorbitol, and fructose (here's a primer on avoiding these substances in packaged foods), while soy can be found in mono- and diglycerides and monosodium glutamate, among many other sources.

3. Buy Sustainable and Ethically Sourced Food

If that's what not to buy, what shopping strategies encourage more environmentally friendly and regenerative methods of growing food? As much as possible, buy a diversity of locally grown, non-BE, fair trade, and organic produce. The good news is, most of the world's farms are still small and family-run, and typically don't grow crops in monocultures. Smaller-scale farms are more likely to practice composting and other sustainable methods that reduce soil erosion and in some cases, even sequester carbon into the ground.

4. Shop Local and Small

To really increase your odds of supporting an environmentally responsible farm, frequent your local farmers market, support a nearby farm stand, or join a CSA (community supported agriculture) collective. It's a great way to connect with small-scale folks who are more likely to practice crop rotation, companion planting, and other sustainable techniques. You can ask them how they grow their food and learn about what they are doing, too. A lot of thoughtful farmers love to be seen for, and to brag about, the good things they do. And by spending money within your local economy, you help your community become more abundant.

5. Go Organic

Buying organic can be another way to steer clear of monocrops, as organic farming methods are typically not compatible with monocropping. While some large-scale organic operations may adopt aspects of monocropping for certain crops, this is more often the exception than the rule.

The majority of organic farms are practicing polyculture and crop rotation, prioritizing soil health, and using cover crops. And by definition, they also can't use most conventional pesticides or bioengineering, so overall their farming practices tend to be better for people and the environment.

6. Grow Your Own Food

You can also lead by example by growing some of your own food. It's a great way to reduce or eliminate your reliance on industrial agriculture in all its problematic forms. You'll also buffer yourself from future disruptions in the world's food supply such as we saw during the early months of the COVID-19 pandemic.

If you have a lawn, you're actually tending your own tiny monoculture of grass. You can show your neighbors (and yourself) what's possible by turning that lawn into something more diverse and useful. You can grow food, or you might also plant a pollinator garden, grow food for birds, or sequester carbon by planting small trees. All of these options can improve the health of the soil and give a hand to your local wildlife.

Say No to Monocropping

Monocropping is an unsustainable farming system that has serious negative impacts on farmers, farmworkers, society, and the environment. What began as a proposed solution to world hunger turned into a race for ever-higher yields and short-term profits.

For humans and the environment to thrive, we need to shift to farming methods that are sustainable and even regenerative, putting more back into the soil than we extract.

And all of us can play an important part by not buying food produced using monocropping methods on large-scale industrial farms - instead supporting local, small-scale, and organically produced food.

Tell us in the comments:
Feature Image: iStock.com/FrostRoomHead

What's one change you can make to support regenerative agriculture?

Do you support farmers' markets, CSAs, or local family farms?

Do you grow any food?

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Monocropping: A Disastrous Agricultural System

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Monocropping - the growing of a single crop over and over on the same piece of land - was invented to increase the food supply and combat hunger. Unfortunately, its unintended consequences threaten greater global food insecurity and worsen climate change.

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Summary

Monocropping - the growing of a single crop over and over on the same piece of land - was invented to increase the food supply and combat hunger. Unfortunately, its unintended consequences threaten greater global food insecurity and worsen climate change. In this article, we'll explore monocropping pros and cons (spoiler alert: more cons than pros) and look at alternative growing methods that you can support.

I'll begin with a simple definition: monocropping is planting and growing one type of plant in the same place, year after year. It's the type of planting that occurs under a type of agriculture called monoculture. If you've ever driven through large agricultural fields completely filled with - say, corn - as far as the eye can see, you're in monoculture country. Monoculture is an agricultural system that involves the planting of a single crop, over and over.

That cornfield was a cornfield last year, and the year before, and it will be a cornfield next year, and into the foreseeable future. It's a monoculture because corn holds a monopoly on that field - no other crops allowed. Because monocultures typically exist at large scale, and can accommodate both conventional and organic farming, the vast majority of the agricultural yield in industrialized countries comes from monocultures.

The question is, why? It's obvious that nature doesn't monocrop. You'll never see an area untouched by humans that is completely dominated by a single species of plant. Nature abhors not just a vacuum, but sameness. Biodiversity is the signature of a natural system.

To understand the reasons behind the global shift to monocultures, and why the agricultural sector has embraced it so wholeheartedly, we have to look at the Green Revolution of the 1960s, and the hopes of the scientists, policy makers, and farmers who were struggling with the twin scourges of poverty and starvation.

How Did Monocropping Come About?

Monocropping was a cornerstone of a series of initiatives intended to address hunger throughout the world by increasing agricultural production. The plan was to develop a wide array of effective pesticides and herbicides, create and teach farmers to use new synthetic fertilizers, breed new and improved "high-yield varieties" (HYVs) of calorically dense crops, and mechanize farm equipment.

The thing that was going to make all of these innovations work was a shift in how agricultural land was used. Traditionally, subsistence farmers and smallholders planted a variety of crops, from grains to pulses to nuts to vegetables to fruits to herbs. But the new technologies and systems of mass production were only going to work, the thinking went, at a large scale.

The big machines were expensive and were designed to handle a specific crop. You don't harvest wheat with the same equipment you use to harvest soybeans. Each crop required a custom application of biocides and fertilizers, as well. In order to get the most out of these technological advances, farming had to change from the workshop model to the factory model.

To replace biodiverse gardens and farms with industrial-sized agriculture, vast swaths of arable land were converted into single-crop use. That way, the farmers could use their new equipment and synthetic chemicals on new HYVs that were bred to tolerate the toxins and make the most of the fertilizers.

As a result, farms around the world increased in size, on average doubling the number of acres under cultivation, in order to produce more food with less labor. With a single farmer able to produce more food, the number of farmers and farm laborers decreased, as human inputs were replaced by machines and by chemicals, often delivered from the air. Over time, more and more farms relied solely on these high-yielding crops, in the form of monocropping, to increase yields and profits.

This logic led to vigorous efforts to bioengineer HYVs to produce heartier, faster-growing, and more resilient crops that define monoculture, rather than relying on trial and error or "natural" breeding.

Now, let's look at some of the monoculture advantages and disadvantages for farmers.

Economic Advantages of Monocropping for Farmers

At first, farmers thought they were on to a good thing. They could now produce more food, and opted to cultivate the one crop that had the greatest profit potential for their soil and climate.

Another monocropping benefit to farmers was the perceived simplicity that saved them time and money, at least in the short-term. Focusing solely on a single crop meant the costs for seeds, equipment, fertilizer, and so on, remained relatively consistent over time, and farmers didn't have to keep looking for new suppliers.

GMOs and Monocropping

As bioengineered (BE) crops (formerly known as GMOs), such as Roundup Ready corn, soybeans, and sugar beets hit the market, the pairing process got even simpler. The farmer had a standing order of glyphosate (one of the active ingredients in Bayer's - formerly Monsanto's - weed killer Roundup) that accompanied every purchase of BE seeds.

Harvesting also got much simpler, as a single machine designed specifically for corn, wheat, or beets could do the work of hundreds of human laborers.

The Emergence of Factory Farms

And last, but certainly not least among the perceived benefits of monocultures, monocrops became inextricably interlinked with a massive expansion in factory farming (or what the industry calls Concentrated Animal Feeding Operations, or CAFOs). Today, much of the world's corn and soy are fed to livestock, not to humans. And CAFO-raised cows, pigs, and chickens represent an almost limitless market for these crops.

The overall result of monocropping, for the first couple of decades, appeared to be mostly positive - at least in terms of the goals of bringing the world more and cheaper calories and increasing the economic security of the farmers who provided it. But all those perceived savings came with hidden costs that added up over time.

Monocultures (and the Green Revolution in general) were promoted to increase the global food supply. While that's happened, there have been several attendant negative consequences. (I'd say "unforeseen consequences" but I'm not sure that's true. It didn't take psychic powers to imagine the effects of a dietary pattern made up largely from factory farmed animal products and processed corn, soy, wheat, and palm oil replacing traditional diets.)

Economic Disadvantages of Monocropping for Farmers

The fundamental issue with monocropping is the "all the eggs in one basket" problem. Crop failure is an inevitable part of farming. For myriad reasons that farmers can't control (most of them falling under the categories of weather, pests, and disease), not all plants thrive and produce a bountiful and profitable harvest every single year.

In a biodiverse ecosystem, a threat to one crop may not be a threat to others. An infestation of stem borers can destroy summer squash but may leave eggplant untouched. An unexpected hail may crush corn and not bother beets.

But when fields contain just one crop, from genetically identical stock, every single plant is equally vulnerable to threat. A pest population can jump easily from one plant to another, especially when there are no other species of plants in between and when crops are planted close together for efficiency.

Monocropping Through History

To see the devastating results when a monocrop comes under threat, check out the history of the Irish potato famine of the 1840s, in which a single genetic variant of potatoes was wiped out by a water mold. The Irish people's dependence on that variant for the majority of their calories meant that over a million people starved to death (an eighth of the entire Irish population), and millions more left the country as refugees.

The history books offer at least one more example of the dangers of relying on monocrops. The world's most popular banana up until the 1950s was a variant known as Gros Michel. You can't find a single one anymore, as the world's supply was knocked out by a fungus that caused Panama disease, which led to banana wilt.

In response, banana producers turned to a less tasty variety, the Cavendish, which is the fruit we know today. Unfortunately, the banana industry didn't learn its lesson, as the Cavendish comprises 99% of the world's banana production, and is now under attack from a new variant of Panama disease called TR4. Dan Koeppel, author of Banana: The Fate of the Fruit That Changed the World , predicted in an NPR interview that the Cavendish could become extinct in the next 10-30 years.

A Trap for Farmers

Monoculture farming can become a trap for the farmers, who often have no choice but to keep purchasing the same seeds and biocides from their agribusiness vendors. Since the seed and agrochemical market was consolidated through mergers and acquisitions into just four main global players, these firms can exert monopolistic power over the farmers who depend on them for seeds and chemical inputs.

The result is increased costs and eroded profit margins for farmers. For example, the price of corn seed rose from under $27 per planted acre of seed to over $90 from 1990 to 2019, far outstripping the rate of inflation. And because monocrop corn farmers have invested so heavily in machinery and infrastructure for growing and harvesting corn, they can't easily exercise free choice and move to another crop or growing model.

The consolidation of seed and supply companies into just a few global companies isn't the end of the "bigger is better" story. Farms themselves are growing larger, by buying up competitors' land or squeezing family farmers out of business. Bigger farms that buy at large scale are rewarded with favorable pricing, which makes it much harder for smaller farms to compete fairly in the marketplace.

Many farmers are forced to buy Bayer seeds and pesticides even if they don't want to. When neighboring farms spray so much of the weed killer dicamba that the air turns hazy, those toxic clouds can waft for two to three miles, killing any soybean plants that aren't bioengineered with dicamba-resistant genes - which is to say, any soybeans not made by Bayer.

Government Subsidies and Monocultures

Not coincidentally, crops produced in a monoculture system are often the same ones that are subsidized by the government (at taxpayer expense, of course). Subsidization is generally delivered in the form of insurance for farmers, guaranteeing that they can sell their crop above a certain price, no matter how low the actual market value for that crop falls. The primary subsidized crops in the US are corn, soy, wheat, and rice.

One out of every five dollars earned by US farmers comes directly from government payouts. These subsidies now buffer farmers not just from the threat of a bad harvest or market crash, but from any marketplace fluctuation. Without subsidies, it would be economic insanity to grow just one or two crops. If the price of corn dropped sufficiently, a farm that relied entirely or mostly on corn for its income could get completely wiped out in a single season.

Finally, subsidies tend to favor large farms, as government payouts often disproportionately go to the biggest producers.

Monoculture's Impacts on the Food Supply & Food Insecurity

At a large scale, monocropping means that poor countries must compete with wealthy ones, in the open market, for a slice of the same global food supply. While traditionally a poor country might be able to grow its own food more cheaply, since wages were also lower, now the entire world bids for commodity crops, which places lower-income nations at a disadvantage.

Because the Green Revolution, in general, and monocropping, in particular, prioritizes efficiency over resilience, there's very little slack in the system when anything goes wrong. And in agriculture, things often do go wrong. Shocks and uncertainties are part of the web of life, which is why nature builds redundancy and diversity into its design.

When humans decimate that diversity through monocropping, any event that leads to a diminished harvest has ripple effects, such as increasing food prices and bringing about greater food insecurity.

The COVID-19 Pandemic and Monocropping

We've seen this play out during the COVID-19 pandemic. The World Bank, a long-time supporter of industrialized agriculture at scale, has admitted that even before the pandemic, monocropped agriculture was collapsing. Here's a remarkable sentence from an article on the World Bank's website: "Even before COVID-19 reduced incomes and disrupted supply chains, chronic and acute hunger were on the rise due to various factors, including conflict, socio-economic conditions, natural hazards, climate change and pests."

As the pandemic unfolded, the article continues, these already scarce resources became even more expensive, with the Agricultural Commodity Price Index increasing 25% from January 2021 to January 2022. Again, the global economically poor were getting priced out of access to food grown on their own lands, which replaced the diverse and healthful horticulture and subsistence practices that had fed their families for generations.

For example, monocropping has displaced regional staples, such as millet, sorghum, and cassava, all culturally and nutritionally important sources of calories throughout much of Africa, the Indian subcontinent, and South America. These foods have been part of traditional healthy diets for hundreds of years, and their displacement threatens global crop diversity.

Monoculture's Impacts on Human Health

Human health also suffers when factory-farmed animal products and processed grains and oils replace traditional whole foods in our diets. Monocultures of corn and palm oil can produce more calories - but far less nutrition - per acre than many other crops. In a world of cheap calories from fractionated foods, malnutrition now refers as much to micronutrient deficiencies as to starvation.

A 2021 research paper on the effects of monocropping on the health of the economically poor highlights the scope of the problem in its first sentence: "Approximately 2 billion people globally are affected by micronutrient deficiencies; much of which is attributed to consuming a monotonous diet of nutrient-deficient staple crops."

Researchers have also documented a relationship between the decrease in dietary diversity and a reduction in the diversity of the human microbiome, with accompanying health challenges. And once a particular strain of beneficial microbes goes extinct in a population, there's a risk that it will never return.

Monocropping also makes it harder for farmworkers to lead lives of dignity, freedom, and security. As pests become resistant to pesticides, and weeds gain resistance to herbicides, agricultural chemical manufacturers have engaged in an arms race, increasing both the quantity and toxicity of chemical applications. While there's some debate about how much exposure to these agents harms consumers, there's no doubt that farmworker exposure to biocides is extremely hazardous.

Monoculture's Impact on Children

Children of mothers who work in pesticide-contaminated fields experience more neurological issues, cognitive impairment, and autism. Girls who grow up exposed to pesticides are at greater risk of infertility and breast cancer.

And throughout the world, children involved in monocropped agriculture, such as on oil palm plantations, are being exploited. Globally, millions of children and adults are essentially enslaved by their agricultural employers.

Environmental Impacts of Monocropping

Humans aren't the only species being harmed by monocropping. The practice is making the planet more susceptible to the ravages of climate change by eroding the land's ability to retain soil and water.

A 2020 study published in the prestigious journal Nature reported that land used for agriculture or tree farms, which comprises 40% of all the non-ice-covered land on the planet, "... is less able to withstand fires, pests, and extreme weather events." And since monocropping farmers lack the agility to shift their planting strategies in the face of climate change, they're extremely vulnerable to these effects.

Pest and Weed Resistance

As we've seen, monocropping and pesticide use go hand in hand. But insects and weeds are rapidly developing resistance to the most widely used pesticides, which creates a vicious cycle - when bioengineered, pesticide-resistant crops fail, agribusiness has doubled down on the strategy by unleashing an "arms war" of increased and more diverse pesticide deployment.

This creates two additional problems. First, since the costs of losing the battle to a pest or pathogen can mean economic disaster for growers and consumers, there's little appetite to risk alternative approaches to pest management that don't involve all-out chemical warfare. Second, climate change means that new pests can now thrive in areas where they until recently had never been seen.

Effect on Pollinators

I'm sorry to say this, but it gets worse. According to a 2019 report by the United Nations' Food and Agriculture Organization (FAO), monocropping, and the pesticide use that accompanies it, now threatens not just plant diversity, but pollinator diversity as well. According to the FAO, over one million species of plants and animals are endangered, including many insect pollinators without whose hard work we would be in real trouble. Of the 20 fastest growing crops in the world, 16 require pollination from insects or other animals. And the danger is not evenly distributed - the most affected countries are the emerging and developing nations in Africa, Asia, and South America.

Disrupts Water Supply

Monocropping also compromises our precious water supply. Fertilizers add nitrates, nitrites, and phosphates to our drinking water, as well as to other bodies of water. Nutrients leach out of our food supply and into water - which not only don't benefit the ecology of rivers, lakes, and ponds but can harm them by creating the conditions for algal blooms that starve aquatic creatures of oxygen.

And impoverished monocropped soil is less able to absorb rainwater, leading to more flooding and more dependency on irrigation.

Decreased Soil Biodiversity

Fertilizers, pesticides, and factory farm waste also harm the ability of soil to sustain life. Monocrops keep adding the same things and depleting the same things, leading to less biodiverse, resilient, and mineral-rich soil (and more dependence on external inputs such as chemical fertilizers).

Monocropping reduces organic matter in soil and can cause significant erosion. This decreases the diversity and abundance of bacterial communities in soil, which in turn undermines plant health and ultimately the health of the humans who eat the plants.

Sustainable Alternatives to Monocultures

As scary and sad as all this is, there's some good news that's also part of the story - we know how to grow food in ways that heal rather than harm the earth and ourselves.

Regenerative Agriculture

What's known as regenerative agriculture, and millennia-old, indigenous growing ways, prioritize practices that mimic natural ecological processes and promote biodiversity. Shifting to regenerative agricultural processes is also one of the most powerful levers at our disposal to combat human-caused global climate chaos.

Regenerative farming focuses on the health of the soil as a top priority. Unlike monocropping, which sacrifices long-term soil health for the short-term production of marketable crops (did none of these scientists or policy makers encounter the story of "the Goose Who Laid the Golden Egg" as a child?), responsible land stewards treat the soil as their primary asset, which produces wealth in the form of food year after year.

Regenerative practices have been shown to enhance soil health, increase soil-based carbon stores (which is good for the climate as well as the plants growing in that soil), improve the physical structure of the soil so that it can hold more carbon, water, and oxygen, and boost soil biodiversity.

Intercrops, Cover Crops, and Polyculture

Other examples of sustainable growing include intercropping - planting more than one crop in a field - and polycultures, which means planting multiple crops together that all help each other grow better.

A well-known example of such a polyculture is the " 3 Sisters " of South and Central America: corn, beans, and squash. Planted together, all three do much better than any one on its own. The squash puts out big leaves that outcompete weeds, but only after the corn and beans have grown taller than the squash leaves. The corn provides a frame upon which the beans can climb. And the beans, like all legumes, fix nitrogen in the soil for the other two sisters. The result is healthier plants and higher yields without the need for so many (or any) chemical fertilizers and herbicides.

Another technique, planting cover crops on part of the land to serve as "green manure" for other crops, adds nutrients and reduces the need to import fertility from outside the farm.

Integrated Pest Management

A sophisticated method of dealing with insects that eat crops, integrated pest management (IMP) also mimics nature, which doesn't try to eliminate species entirely but keeps them in check through predation. Rather than killing life and reducing biodiversity, IMP takes the opposite approach, nurturing the presence of organisms that prey on the critters that prey on the crops.

Agroforestry

Nature, of course, doesn't grow food in rows, but produces its bounty in meadows, orchards, glens, jungles, and forests. All these ecosystems are characterized by robust biodiversity that's expressed in vertical layers, with roots, ground cover, shrubs, bushes, short trees, and tall trees all sharing the sun, soil, and rain to their collective benefit. Agroforestry is an approach to growing crops that mimics the design and function of a grove, with crops and trees interplanted.

While there is always more to learn, and there are many new breakthroughs to be had, this isn't entirely new science. Indigenous farmers have been refining these techniques for millennia, to protect their crops from extreme weather events, maximize the resources that can be harvested from a single location (legumes and lettuce and lumber, oh my!), increase soil fertility, and store carbon.

Indigenous farmers also save and treasure many varieties of each crop, which increases the odds that any disease that attacks a particular strain won't be able to destroy the entire crop. And the genetic variability also provides nutritional and usage variability, so the community can get far more from its arable land than a single crop would provide. This approach truly provides the farmers with land for life, rather than cash crops for a few seasons.

What Can You Do as a Consumer?

Given the urgency of our collective generational challenge - to produce food sustainably and ethically so that all may be fed - what can each of us do to participate in the shift from industrial monocropping to regenerative agriculture?

At a personal level, we can start by directing our hard-earned money towards foods that align with our values.

1. Eliminate Factory Farmed Meat and Dairy

A strategy with a particularly big impact is to steer clear of industrially produced animal products such as meat and dairy. That's because much of the monocropped and bioengineered corn and soy grown around the world goes to feed livestock.

2. Cut Down on Processed Foods

You can also say no to monocropping by reducing your purchases of processed foods, especially those made with palm oil, non-organic corn, and soy by-products. This isn't as simple as looking for "corn" or "soy" on a food label: corn by-products can hide behind words like maltodextrin, sorbitol, and fructose (here's a primer on avoiding these substances in packaged foods), while soy can be found in mono- and diglycerides and monosodium glutamate, among many other sources.

3. Buy Sustainable and Ethically Sourced Food

If that's what not to buy, what shopping strategies encourage more environmentally friendly and regenerative methods of growing food? As much as possible, buy a diversity of locally grown, non-BE, fair trade, and organic produce. The good news is, most of the world's farms are still small and family-run, and typically don't grow crops in monocultures. Smaller-scale farms are more likely to practice composting and other sustainable methods that reduce soil erosion and in some cases, even sequester carbon into the ground.

4. Shop Local and Small

To really increase your odds of supporting an environmentally responsible farm, frequent your local farmers market, support a nearby farm stand, or join a CSA (community supported agriculture) collective. It's a great way to connect with small-scale folks who are more likely to practice crop rotation, companion planting, and other sustainable techniques. You can ask them how they grow their food and learn about what they are doing, too. A lot of thoughtful farmers love to be seen for, and to brag about, the good things they do. And by spending money within your local economy, you help your community become more abundant.

5. Go Organic

Buying organic can be another way to steer clear of monocrops, as organic farming methods are typically not compatible with monocropping. While some large-scale organic operations may adopt aspects of monocropping for certain crops, this is more often the exception than the rule.

The majority of organic farms are practicing polyculture and crop rotation, prioritizing soil health, and using cover crops. And by definition, they also can't use most conventional pesticides or bioengineering, so overall their farming practices tend to be better for people and the environment.

6. Grow Your Own Food

You can also lead by example by growing some of your own food. It's a great way to reduce or eliminate your reliance on industrial agriculture in all its problematic forms. You'll also buffer yourself from future disruptions in the world's food supply such as we saw during the early months of the COVID-19 pandemic.

If you have a lawn, you're actually tending your own tiny monoculture of grass. You can show your neighbors (and yourself) what's possible by turning that lawn into something more diverse and useful. You can grow food, or you might also plant a pollinator garden, grow food for birds, or sequester carbon by planting small trees. All of these options can improve the health of the soil and give a hand to your local wildlife.

Say No to Monocropping

Monocropping is an unsustainable farming system that has serious negative impacts on farmers, farmworkers, society, and the environment. What began as a proposed solution to world hunger turned into a race for ever-higher yields and short-term profits.

For humans and the environment to thrive, we need to shift to farming methods that are sustainable and even regenerative, putting more back into the soil than we extract.

And all of us can play an important part by not buying food produced using monocropping methods on large-scale industrial farms - instead supporting local, small-scale, and organically produced food.

Tell us in the comments:
Feature Image: iStock.com/FrostRoomHead

What's one change you can make to support regenerative agriculture?

Do you support farmers' markets, CSAs, or local family farms?

Do you grow any food?

Read Next:

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Monocropping: A Disastrous Agricultural System

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Monocropping - the growing of a single crop over and over on the same piece of land - was invented to increase the food supply and combat hunger. Unfortunately, its unintended consequences threaten greater global food insecurity and worsen climate change.

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导语：我们地球的百分之70都是海洋，是大海孕育了我们的生命，每一个人都应该学会保护海洋。下面是小编整理收集的海洋污染作文三篇，欢迎阅读！

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What Is Monocropping and Why Is It Bad for the Environment?

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Monocropping (or monoculture) has doubled global food production. But it’s not sustainable, and there are better alternatives.

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By Stephanie Rochford
Sustainability Studies student

Mono-crop farming is the practice of growing large amounts of one crop on the land. This practice was recognized as a very economical way to provide farmers with a way to earn money, grow large amounts of a staple crop, like soy, corn, or wheat, and sell these crops off to any company willing to use it for food or fuel.

The problem with this is that the destruction that is done to the environment when mono-cropping is being engaged is far greater than the benefits it brings. The depletion of the nutrients in the soil, the use of pesticides on the crops, and not the entire crop is used for food. This leaves land that is even more reliant on the pesticides to fight off predators which in return puts more chemicals into the system. Finally, the entire reason we grow food is to eat it. This type of farming does not provide the diversity needed in our diets or to our ecosystem.

A clear way to send a message that monocropping is unacceptable as the major source of farming is to support local, organic, diverse farms. These farms provide the variety of foods we want and need, they support themselves in growing, and they do not leave the environment in worse condition.

Finally, if monocropping is controlled by a large entity, like a corporation or the government, it is in our best interests to make smart dollar decisions in supporting the companies that consider the environment without being told to do so. Also, it might be worth having farms that destroy the land, to either pay a tax, or find a way to offset their farms. Another great idea is found in the Mother Jones website, explaining how planting crops on top of the monocrops in the off season will actually help such farms in weaning off of the pesticides. Fewer pesticides lead to better food and a friendlier climate.

I believe these things start with a discussion, and if we can get the right politicians on board we might see legislation that at least asks for such destructive farms to acknowledge their role in the environment. For now, it appears that the money and big business with monocropping serves few, and those few have determined that it is without worry that they can continue this practice.

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By Stephanie Rochford Sustainability Studies student Mono-crop farming is the practice of growing large amounts of one crop on the land. This practice was recognized as a very economical way to provide farmers with a way to earn money, grow large amounts of a staple crop, like soy, corn, or wheat, and sell these crops off to any company willing to use it for food or fuel.

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Extinction | Definition & Types - Lesson | Study.com

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What does “extinct” mean? Learn the mass extinction definition and about other types of extinction. Explore how human activity impacts extinctions…

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Monoculture | Definition, Farming, Advantages, Disadvantages, Examples, & Facts | Britannica

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Monoculture, in agriculture, the practice of growing a single crop on a given acreage. While monoculture crops are sometimes rotated year to year, continuous monoculture, or mono-cropping, in which the same crop is grown year after year, has become one of the dominant paradigms in modern industrial

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https://www.ifaw.org/international/journal/five-biggest-threats-to-ocean

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The roots of the concept of mental health

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This paper reviews the origins of the current concept of mental health, starting from the mental hygiene movement, initiated in 1908 by consumers of psychiatric services and professionals interested in improving the conditions and the quality of…

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Skip to content

1: Kalundborg Symbiosis - the world's first working industrial symbiosis

The Kalundborg Symbiosis is an industrial symbiosis, where a by-product or residual product of one enterprise is used as a resource by another enterprise. An industrial symbiosis combines the logic from nature's ecosystems with the rationales of the economic system. Through local collaboration, public and private enterprises buy and sell residual products from one another, gaining mutual economic and environmental benefits in doing so. Kalundborg Symbiosis started more than 40 years ago and is one of the most well-known and well-described industrial symbioses in the world. It has also inspired others to produce more for less. It is strongly connected to the creation of the first and only symbiosis centre in the world, which works to identify and facilitate new industrial symbioses in Denmark. Kalundborg Symbiosis includes world-leading as well as smaller companies, but whatever the size, the benefits of industrial symbiosis are clear:

Cost reductions and less emissions

Growth for less resources

More competitive enterprises

More resilient societies and enterprises

(Courtesy: Novo Nordisk, Novozymes, Statoil Refining, Gyproc, KaraNoveren, Kalundborg Utility, Kalundborg Municipality and Symbiosis Center Denmark).

2: A circular subscription concept

VIGGA was born as a circular concept. The idea was to create a new way of consuming, based upon sharing and circulating high-quality products. Through a circular subscription concept, VIGGA offers high-quality children's clothes, produced under proper conditions, at an attractive price. This is possible because the same piece of clothing will be shared by several children and the quality of the clothing is so high:

For a monthly subscription fee, the customers get 20 pieces of clothes in their child's size

When the clothes become too small, they are replaced by new sets of clothes one size bigger

After a quality inspection, the returned clothes are then washed professionally

Subsequently, the clothes are delivered to another baby, resulting in a circular process

The concept creates an incentive for textile companies to produce in as high a quality as possible. The higher the quality, the more children can make use of the same piece of clothes and the higher the profit becomes. Furthermore, textile waste is reduced by 70-85%. (Courtesy: VIGGA)

3: A circular travel solution

Cars are by far one of the most under-utilised resources in modern life. In Denmark, an average car transports 1.4 people on the road and spends about 23 hours per day taking up parking space. Empty car seats are the largest excess capacity in the transport industry, and this inefficiency has a negative impact on the environment and is expensive for car owners. GoMore's platform offers a service that enables drivers to invite people for a ride on an already planned journey. This increases the number of people in cars and reduces the number of cars on the streets, making car trips more efficient and better for the environment. It is a travel solution which is cheaper for both the car owner and the passenger. Since GoMore was established in 2005, more than 1 million users have visited and used the service. As a result, more than 300,000 seats have been sold in Denmark alone, making GoMore a European leader in combining ridesharing and peer-to-peer car rental, and Scandinavia's leading business in the sharing economy. (Courtesy: GoMore)

4: Recycling of artificial turf

As the first in the world, Re-Match uses patented state-of-the-art technology to separate worn-out artificial turf into raw, clean components, which can then be re-used or recycled in the turf industry or in other industries. Re-Match is able to separate every part of the worn-out synthetic turf into rubber granules, sand and plastic fibres. The technology is so effective that almost 100% of the components can be either reused or recycled.

Every artificial turf pitch that is recycled by Re-Match results in a saving of 400 tonnes of CO ₂, when compared to incineration, which is equivalent to 1.4 million plastic bags, or 250 tonnes of waste. Conversely, the process used to separate artificial turf emits less than 20 tonne of CO ₂ per pitch.

5: Developing the world's first biodegradable beer bottle

One of the challenges the Carlsberg Group focuses on is packaging, as around 45% of their CO2 emissions come from the company's packaging. They want to reduce this number by encouraging consumers to recycle more, minimise material usage and by developing new environmentally friendly packaging types. The Carlsberg Group have initiated a partnership with Danish company ecoXpac, Innovation Fund Denmark and the Technical University of Denmark to develop the world's first fully biodegradable beer bottle made from wood fibre - the Green Fiber Bottle. The bottle will be as light as a PET bottle, while having the advantage of being created from bio-based sources.

The project is one of the activities in the Carlsberg Circular Community, which is the Carlsberg Group's partnership platform to develop more sustainable products with partners from across the world. The community aims to eliminate the concept of waste by creating sustainable products and a more circular economy in an increasingly resource-scarce world. (Courtesy: Carlsberg Group, ecoXpac, Danish Technical University, Innovation Fund Denmark)

6: Potentials in potato starch production

Danish potato processing cooperative KMC, which produces a variety of potato starch ingredients for the food industry, has been a pioneer in adding value to its side streams. KMC is headquartered in central Jutland and operates a number of production sites in Denmark, staying close to its suppliers and owners, the potato growers. Since introducing potato-based feed proteins for the agricultural sector in the 1980s, KMC has advanced and refined the residuals of potato starch production.

In 2005, KMC began transforming residual potato fibres into a valuable protein-rich food additive for the food industry. Splitting and refining the side streams from potato starch production helps maximise output of each potato for the economic benefit of the potato growers, while the use of potato fibres allows the food industry to efficiently increase the nutritional value of its products. (Courtesy: KMC)

7: Re-using old bricks to build a greener future

The driving force behind the founding of the company "Gamle Mursten" ("Old Bricks") was the desire to prevent resources of natural bricks from being wasted. Since its founding, "Gamle Mursten" has expanded greatly, and is now a large-scale cleantech production company with patented cleaning technology which ensures that building waste can be reused without the use of any chemicals.

The old bricks are collected, cleaned with vibration technology, manually checked one by one and finally stacked by robots before being shipped to new sites. Saving more than 95% of the energy otherwise used to manufacture new bricks, this method of re-using old bricks is an example of perfect circular economy passing the resources of one generation on to a new one. By applying its method to two thousand bricks, "Gamle Mursten" also prevents the emission of one tonne of CO2. Realdania Byg and 3XN Architects used 300,000 old bricks making the Castle of Hindsgavl hotel (see picture), saving the environment of 150 tons CO2. (Courtesy: Realdania Byg and 3XN Architects)

8: Used insulation, discarded porcelain and sanitaryware upcycled into new insulation

With over 30% of Denmark's waste coming from construction, upcycling of used building materials has become an area of increased focus. As a result, traditional disposal methods that send waste insulation to landfill sites and crush porcelain and sanitaryware to make road fill are being replaced by a new, greener alternative jointly developed by three Danish companies.

Construction waste from Danish recycling centres is delivered to RGS90, a company which specialises in the processing, sorting, removing and recycling of waste products. Here, all unwanted materials are removed. Recyclable ROCKWOOL insulation and ROCKFON acoustic panels are then separated from the unrecyclable insulation before being granulated. Porcelain and sanitaryware are crushed before being sent to the ROCKWOOL production facility, where they are used to manufacture new, recyclable insulation. (Courtesy: RGS90, ROCKWOOL and Combineering A/S)

9: Grundfos pumps contribute to energy saving heating and cooling

Pumps are one example of a type of devices used in many industrial applications. They play a vital role in dairies, breweries, slaughterhouses, textile and chemical production, power stations, shipping etc. More than 2/3 of all pumps installed today are inefficient and use up to 60% too much energy. Additionally, most pumps currently installed are larger than necessary and often run continuously at their maximum speed. Replacing inefficient pumps results in significant savings, reduces energy waste and thereby contributes to the circular economy by minimising the environmental footprint.

At the Yokohama Rubber factory in Japan, Grundfos switched out the main pump delivering water to cool the factory´s production line. This enabled the company to drastically reduce energy costs by more than 50% while also contributing towards its commitment to reduce CO2-emissions. Across Grundfos' own facilities, a flagship initiative has been running for several years now to replace all inefficient pumps and motors worldwide with high-efficiency Grundfos solutions. As a result, Grundfos' annual energy consumption has been reduced by more than 8.000.000 kWh. (Courtesy: Grundfos)

10: Optimising side streams

Danish Crown, one of the world's biggest pork producers, is cooperatively owned by Danish farmers who are both our suppliers and owners. Production and possibilities for optimising side streams is seen across the value chain from farm level to slaughterhouse. The value chain is no stronger than its weakest link, the result being today that Danish Crown represents one of the most efficient meat producers in the world. The secret behind Danish Crown is the focus not only on producing meat, but also on producing and recycling other products such as sustainable energy, fuels, feed, nutrients and inputs for the pharmaceutical industry.

Resource efficiency is a key part of the DNA. Investments in the value chain, such as breeding of animals, new effective stables, feed optimisation, recycling of nutrients, as well as improving energy and water efficiency, logistics and utilisation of side-streams, are interconnected. They generate valuable knowledge-sharing through the value chain, ultimately benefiting the owners. Based on this philosophy, Danish Crown demonstrates that they produce more with less, creating more value for the customers, suppliers, owners as well as society in general, the climate and environment. Circular economy principles are therefore nothing new to Danish Crown. (Courtesy: Danish Crown)

Explore related publications

From a linear to a circular economy

Experiences from Denmark and New York on closing the loop through partnerships and circular business models

The business of a circular future

How business models can accelerate the transition to a circular economy

Energy renovation of buildings

How to realise the untapped potential of the built environment with energy renovation of buildings.

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10 Examples of Circular Economy Solutions

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Skip to content The Kalundborg Symbiosis is an industrial symbiosis, where a by-product or residual product of one enterprise is used as a resource by another enterprise. An industrial symbiosis combines the logic from nature's ecosystems with the rationales of the economic system.

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Sport pertains to any form of physical activity or game,[1] often competitive and organized, that aims to use, maintain, or improve physical ability and skills while providing enjoyment to participants and, in some cases, entertainment to spectators.[2] Sports can, through casual or organized participation, improve participants’ physical health. Hundreds of sports exist, from those between single contestants, through to those with hundreds of simultaneous participants, either in teams or competing as individuals. In certain sports such as racing, many contestants may compete, simultaneously or consecutively, with one winner; in others, the contest (a match) is between two sides, each attempting to exceed the other. Some sports allow a “tie” or “draw”, in which there is no single winner; others provide tie-breaking methods to ensure one winner. A number of contests may be arranged in a tournament producing a champion. Many sports leagues make an annual champion by arranging games in a regular sports season, followed in some cases by playoffs.

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Countries paving the way for a more sustainable future prioritise renewable energy, effective waste management systems & strong environmental regulations

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海洋垃圾對魚類的健康有什麼影響？

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海洋垃圾對魚類的健康有什麼影響？

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海龜吃到塑料後會發生什麼事？

海洋垃圾如何影響海洋食物鏈？

這些問題能幫助你更深入了解海洋垃圾的影響。你最想研究哪個問題呢？

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What sports can do to your well being and your physical health.

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Benjamin Valle Communication & Brand Content Officer - Central Test

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Benefits of sport for your well-being | Central Test

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Physical exercise is essential for your physical and mental well-being. However, our often-sedentary lifestyles can make it difficult to keep active and can be a source of stress, fatigue, or even hormonal imbalances.

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Engaging in sports and regular physical activity has numerous benefits for overall well-being. Physically, sports contribute to improved cardiorespiratory endurance, muscular strength, flexibility, and body composition, which are essential components of physical fitness. Regular participation in sports can help prevent chronic diseases such as cardiovascular disease, stroke, diabetes, and certain types of cancer. It also reduces the risk of early death, falls, and weight gain, and can improve sleep quality and mood.

Mentally, sports can enhance cognitive function across various age groups, from young adults to the elderly. Physical activity promotes synapse formation in the brain, which is crucial for learning and memory. Additionally, sports can improve mood and energy levels, offering a natural way to combat depression and anxiety.

Socially, sports play a significant role in socialization, helping individuals develop a sense of identity and community. Participation in sports can foster relationships and build character, as individuals learn to manage emotions, teamwork, and competition. The emotional experiences associated with sports, such as anticipation, excitement, and camaraderie, contribute to a sense of belonging and national identity.

Overall, sports provide a holistic approach to enhancing physical, mental, and social well-being, making them a valuable component of a healthy lifestyle.

(I searched that up)

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Mental health disorders in children are on the rise. But, even with up to 1 in 5 children experiencing a mental health disorder, many people are uncomfortable talking about children's mental health. Learning more about mental health disorders in children and the stigmas attached to them can make the topic less scary.

Nicholas J. Westers, Psy.D., ABPP, a clinical psychologist at Children's Health℠ and Associate Professor at UT Southwestern explains, "Reducing mental health stigma is more than just talking about it. It's how we address mental health as a society and with our children."

Dr. Westers shares ways parents can help end mental health stigma.

Why is it important to talk about children's mental health?

It's important to talk to children about mental health because if you don't, they will get their information from someone or somewhere else. That source may not be reliable or accurate.

One of the most common ways children are exposed to mental health is through media. And those depictions aren't always accurate or favorable.

"Mental health disorders are often portrayed incorrectly in movies and TV shows," Dr. Westers says. "They can paint characters struggling with a mental health disorder as incompetent or even violent."

On the other hand, when parents and children have an open and honest conversation about any topic - including mental health - children feel comfortable going to a source they can trust to ask questions without being judged.

How does stigma affect mental health?

One of the biggest negative effects of stigmas surrounding mental health is that they can keep people from seeking treatment. It's estimated that almost half of the children who struggle with a mental health disorder do not receive the care and support they need.

Even for children and families who do not have a diagnosable mental health issue, good mental health includes the presence of healthy habits. Stigma can prevent children and families from talking about, exploring and addressing any feelings they have, which is an important part of raising healthy, resilient kids.

What are common stigmas surrounding mental health?

At its core, stigma is the sense - whether conscious or unconscious - that someone is different than you and that difference is negative. Stigma separates "us" versus "them." Common public stigmas surrounding mental health include:

People with mental health disorders are weak or lazy:
This may occur when someone thinks, "I've struggled with similar issues and turned out fine, so people with mental health disorders need to take more responsibility," or, "I had the same issues, but I've never used a mental health disorder as an excuse to miss school, practice, chores or my job."

People with mental health disorders are prone to violence:
An example of this is when statements are made about tragedies or acts of violence such as school shootings, such as, "Only a crazy or mentally ill person would do something like this." This often categorizes hatred as a mental health disorder, which it is not.

People with mental health disorders are incompetent:
This stigma might show through thoughts like, "I'm not sure we should hire someone who is so open about their history of depression," or, "My child suffers from social anxiety and needs me to always be there for him/her."

Public stigma surrounding mental health can lead to self-stigma and decreased help-seeking. Examples of thoughts guided by self-stigma include:

"I need to see a therapist, but if my friends/peers find out I leave class to see a therapist they will make fun of me. I'll get through this on my own."

"I've always felt anxious and depressed, and I'll always feel like this."

"I must be going crazy. No one else is going through this."

These perceptions about mental health disorders and people diagnosed with a disorder are wrong.

"Research and experience dispel each of these stigmas time and time again," says Dr. Westers. "For example, we know treatment can be very effective so that a mental health disorder isn't always something a person struggles with the rest of their life, and we know that individuals diagnosed with mental health disorders are no more likely to commit acts of violence than those without a mental health disorder."

Dr. Westers says it's important to know that many people with a mental health disorder go on to be thriving, successful and an important part of our society.

How can families end stigma around mental health?

Families can end mental health stigma by talking about mental health in the right way.

"It takes a lot more than just awareness about mental health to address the stigma surrounding it," Dr. Westers explains. "Awareness is realizing that one in five kids have a mental health disorder. Removing stigma means recognizing we are all more alike than different, refraining from making stigmatizing comments such as those mentioned above, having an ongoing conversation with your children, family members and friends, and modeling love and acceptance."

Dr. Westers shares five tips to help parents break the stigma of mental health.

1. Educate yourself and your children about mental health

The first step in reducing mental health stigma is providing accurate information about mental health disorders. This can include sharing straightforward facts about disorders, like the symptoms of depression or anxiety.

Education can also include using correct terminology. When speaking about a mental health disorder, separate the person from their diagnosis. "We don't call people bipolar. Instead, we say a person has a bipolar disorder," explains Dr. Westers. "This simple shift demonstrates that a person is so much more than a diagnosis."

Parents can also dispel myths about mental health to provide important education:

Mental health disorders are treatable. When parents frame mental health disorders as treatable conditions, children can start to feel more hopeful about seeking treatment.

Mental health is part of your overall health. Children know they need to see a doctor when they have an illness or injury. The same is true when they struggle with a mental health issue. Talking about mental health as part of their overall health helps remove any shame or embarrassment.

2. Give context around mental health disorders

When children see or hear others - whether it's someone famous or someone in their social circle - talk openly and honestly about mental health, it gives them a better context for the topic.

"One dangerous thing about mental health stigma is it creates an 'us' versus 'them' situation," Dr. Westers says. "But, when a child, teen or adult, realizes someone they know or admire struggles with a mental health disorder, it starts to knock down some of those lines and decreases shame. Celebrities like Michael Phelps and Kristen Bell have helped shine a spotlight on mental health. Kids now see someone who struggled with depression, anxiety or suicidal thoughts and got help. It's a much more positive, hopeful and accurate depiction than what stigma presents."

3. Explain mental health as a continuum

When you talk about mental health as a continuum, or as a range, it helps others identify with those diagnosed with a mental health condition.

"Everyone feels sad from time to time - sometimes more than at other times. And sometimes, those feelings are so intense, you can't get out of bed, can't eat," says Dr. Westers. "Explaining something like depression on a continuum helps children see that people with depression aren't that different from them. It highlights how we are alike instead of how we are different."

4. Show solidarity with others

Showing solidarity with someone diagnosed with a mental health disorder is the next step in removing stigma. It takes us one step closer to demonstrating sympathy and showcasing empathy.

Showing solidarity means not telling people "they're fine" when depressed or that they "just need to cheer up" or "get over it." It's about taking the time to listen and support without judgment. It's offering to walk your friend to the school counselor to get them the help they need. It's saying, "I stand with you," and then following it up with your actions.

5. Share messages of recovery

Messages of recovery are among the strongest and most hopeful tools in removing stigma.

"We're changed by stories and by people we can relate to," explains Dr. Westers. "Parents should feel empowered and encouraged to share how they, a family member or close friend, overcame a mental health condition. Their children do not need to know all the details, but stories take away the negative perceptions and show that anyone can experience a mental health disorder and - most importantly - can learn to manage it and even recover."

Learn more

Children's Health provides comprehensive services to support children's and teens' mental health. Learn more about our Pediatric Psychiatry and Psychology Programs.

You can also access emotional care and support from the comfort of your home with Virtual Visit Behavioral Health. With a behavioral health care appointment, you can speak to a board-certified psychiatrist or licensed therapist using video technology. Learn more about Virtual Visit Behavioral Health.

Sign Up

Stay current on the health insights that make a difference to your children. Sign up for the Children's Health newsletter and have more tips sent directly to your inbox.

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5 Ways to End Mental Health Stigma - Children's Health

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Mental health disorders in children are on the rise. But, even with up to 1 in 5 children experiencing a mental health disorder, many people are uncomfortable talking about children's mental health. Learning more about mental health disorders in children and the stigmas attached to them can make the topic less scary.

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y2mate.com - Monoculture vs Polyculture  FoodUnfolded Animated Short_360p

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y2mate.com - Polyculture Planting  Incredible Way to Increase Production in a Small Space Vegetable Garden_360p

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Climate change is set to wreak havoc on South Africa (SA)'s agri-food system. Increasing temperatures, lower and more erratic rainfall, and more extreme weather events will characterise the climate in Southern Africa over the next decades. This poses challenges for food production and food security. At the same time, SA's agri-food system is one of [...]

Minister Steenhuisen, when can we expect the Registrar to respond? Today marks a year since we called for a review of the registration of 2,4-D in South Africa, in a letter to the Registrar: Act No. 36 of 1947, Mr Jonathan Mudzunga. With no substantive response forthcoming, despite substantiation in a further submission, and persistent [...]

ACB executive director Mariam Mayet and research and advocacy officer Sabrina Masinjila recently participated in the fourth edition of the International Farmer Seeds Gathering, this year held in Antibes, France. Co-organised by Reseau Semences Paysannes, SOL and the Maison des Semences Maralpines in collaboration with the European network Let's Liberate Diversity!, the gathering was a [...]

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The African Centre for Biodiversity (ACB) is a research and advocacy organisation working towards food sovereignty and agroecology in Africa, with a focus on biosafety, seed systems and agricultural biodiversity. We are committed to dismantling inequalities and resisting corporate-industrial expansion in Africa's food and agriculture systems.

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Changes in surface air temperature over the past 50 years.[1] The Arctic has warmed the most, and temperatures on land have generally increased more than sea surface temperatures.

Earth's average surface air temperature has increased almost 1.5°C (about2.5 °F) since the Industrial Revolution. Natural forces cause some variability, but the 20-year average shows the progressive influence of human activity.[2]

In common usage, climate change describes global warming-the ongoing increase in global average temperature-and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is primarily caused by humans burning fossil fuels since the Industrial Revolution. Fossil fuel use, deforestation, and some agricultural and industrial practices add to greenhouse gases. These gases absorb some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere. Carbon dioxide, the primary greenhouse gas driving global warming, has grown by about 50% and is at levels unseen for millions of years.

Climate change has an increasingly large impact on the environment. Deserts are expanding, while heat waves and wildfires are becoming more common. Amplified warming in the Arctic has contributed to thawing permafrost, retreat of glaciers and sea ice decline. Higher temperatures are also causing more intense storms, droughts, and other weather extremes. Rapid environmental change in mountains, coral reefs, and the Arctic is forcing many species to relocate or become extinct. Even if efforts to minimise future warming are successful, some effects will continue for centuries. These include ocean heating, ocean acidification and sea level rise.

Climate change threatens people with increased flooding, extreme heat, increased food and water scarcity, more disease, and economic loss. Human migration and conflict can also be a result. The World Health Organization (WHO) calls climate change the greatest threat to global health in the 21st century. Societies and ecosystems will experience more severe risks without action to limit warming. Adapting to climate change through efforts like flood control measures or drought-resistant crops partially reduces climate change risks, although some limits to adaptation have already been reached. Poorer communities are responsible for a small share of global emissions, yet have the least ability to adapt and are most vulnerable to climate change.

Many climate change impacts have been felt in recent years, with 2023 the warmest on record at +1.48 °C (2.66 °F) since regular tracking began in 1850. Additional warming will increase these impacts and can trigger tipping points, such as melting all of the Greenland ice sheet. Under the 2015 Paris Agreement, nations collectively agreed to keep warming "well under 2 °C". However, with pledges made under the Agreement, global warming would still reach about 2.7 °C (4.9 °F) by the end of the century. Limiting warming to 1.5 °C will require halving emissions by 2030 and achieving net-zero emissions by 2050.

Fossil fuel use can be phased out by conserving energy and switching to energy sources that do not produce significant carbon pollution. These energy sources include wind, solar, hydro, and nuclear power. Cleanly generated electricity can replace fossil fuels for powering transportation, heating buildings, and running industrial processes. Carbon can also be removed from the atmosphere, for instance by increasing forest cover and farming with methods that capture carbon in soil.

Terminology

Before the 1980s it was unclear whether the warming effect of increased greenhouse gases was stronger than the cooling effect of airborne particulates in air pollution. Scientists used the term inadvertent climate modification to refer to human impacts on the climate at this time. In the 1980s, the terms global warming and climate change became more common, often being used interchangeably. Scientifically, global warming refers only to increased surface warming, while climate change describes both global warming and its effects on Earth's climate system, such as precipitation changes.

Climate change can also be used more broadly to include changes to the climate that have happened throughout Earth's history. Global warming-used as early as 1975-became the more popular term after NASA climate scientist James Hansen used it in his 1988 testimony in the U.S. Senate. Since the 2000s, climate change has increased usage. Various scientists, politicians and media now use the terms climate crisis or climate emergency to talk about climate change, and global heating instead of global warming.

Global temperature rise

Global surface temperature reconstruction over the last 2000 years using proxy data from tree rings, corals, and ice cores in blue.[36] Directly observed data is in red.[37]

Temperature records prior to global warming

Over the last few million years human beings evolved in a climate that cycled through ice ages, with global average temperature ranging between 1 °C warmer and 5-6 °C colder than current levels. One of the hotter periods was the Last Interglacial between 115,000 and 130,000 years ago, when sea levels were 6 to 9 meters higher than today. The most recent glacial maximum 20,000 years ago had sea levels that were about 125 meters (410 ft) lower than today.

Temperatures stabilized in the current interglacial period beginning 11,700 years ago. Historical patterns of warming and cooling, like the Medieval Warm Period and the Little Ice Age, did not occur at the same time across different regions. Temperatures may have reached as high as those of the late 20th century in a limited set of regions. Climate information for that period comes from climate proxies, such as trees and ice cores.

Warming since the Industrial Revolution

There has been an increase in ocean heat content during recent decades as the oceans absorb over 90% of the heat from global warming.[46]

Around 1850 thermometer records began to provide global coverage. Between the 18th century and 1970 there was little net warming, as the warming impact of greenhouse gas emissions was offset by cooling from sulfur dioxide emissions. Sulfur dioxide causes acid rain, but it also produces sulfate aerosols in the atmosphere, which reflect sunlight and cause so-called global dimming. After 1970, the increasing accumulation of greenhouse gases and controls on sulfur pollution led to a marked increase in temperature.

Ongoing changes in climate have had no precedent for several thousand years. Multiple independent datasets all show worldwide increases in surface temperature, at a rate of around 0.2 °C per decade. The 2013-2022 decade warmed to an average 1.15 °C [1.00-1.25 °C] compared to the pre-industrial baseline (1850-1900). Not every single year was warmer than the last: internal climate variability processes can make any year 0.2 °C warmer or colder than the average. From 1998 to 2013, negative phases of two such processes, Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) caused a so-called " global warming hiatus". After the hiatus, the opposite occurred, with years like 2023 exhibiting temperatures well above even the recent average. This is why the temperature change is defined in terms of a 20-year average, which reduces the noise of hot and cold years and decadal climate patterns, and detects the long-term signal.

A wide range of other observations reinforce the evidence of warming. The upper atmosphere is cooling, because greenhouse gases are trapping heat near the Earth's surface, and so less heat is radiating into space. Warming reduces average snow cover and forces the retreat of glaciers. At the same time, warming also causes greater evaporation from the oceans, leading to more atmospheric humidity, more and heavier precipitation. Plants are flowering earlier in spring, and thousands of animal species have been permanently moving to cooler areas.

Differences by region

Different regions of the world warm at different rates. The pattern is independent of where greenhouse gases are emitted, because the gases persist long enough to diffuse across the planet. Since the pre-industrial period, the average surface temperature over land regions has increased almost twice as fast as the global average surface temperature. This is because oceans lose more heat by evaporation and oceans can store a lot of heat. The thermal energy in the global climate system has grown with only brief pauses since at least 1970, and over 90% of this extra energy has been stored in the ocean. The rest has heated the atmosphere, melted ice, and warmed the continents.

The Northern Hemisphere and the North Pole have warmed much faster than the South Pole and Southern Hemisphere. The Northern Hemisphere not only has much more land, but also more seasonal snow cover and sea ice. As these surfaces flip from reflecting a lot of light to being dark after the ice has melted, they start absorbing more heat. Local black carbon deposits on snow and ice also contribute to Arctic warming. Arctic surface temperatures are increasing between three and four times faster than in the rest of the world. Melting of ice sheets near the poles weakens both the Atlantic and the Antarctic limb of thermohaline circulation, which further changes the distribution of heat and precipitation around the globe.

Future global temperatures

CMIP6 multi-model projections of global surface temperature changes for the year 2090 relative to the 1850-1900 average. The current trajectory for warming by the end of the century is roughly halfway between these two extremes.[22][81][82]

The World Meteorological Organization estimates a 66% chance of global temperatures exceeding 1.5 °C warming from the preindustrial baseline for at least one year between 2023 and 2027. Because the IPCC uses a 20-year average to define global temperature changes, a single year exceeding 1.5 °C does not break the limit.

The IPCC expects the 20-year average global temperature to exceed +1.5 °C in the early 2030s. The IPCC Sixth Assessment Report (2023) included projections that by 2100 global warming is very likely to reach 1.0-1.8 °C under a scenario with very low emissions of greenhouse gases, 2.1-3.5 °C under an intermediate emissions scenario, or 3.3-5.7 °C under a very high emissions scenario. In the intermediate and high emission scenarios, the warming will continue past 2100.

The remaining carbon budget for staying beneath certain temperature increases is determined by modelling the carbon cycle and climate sensitivity to greenhouse gases. According to the IPCC, global warming can be kept below 1.5 °C with a two-thirds chance if emissions after 2018 do not exceed 420 or 570 gigatonnes of CO ₂. This corresponds to 10 to 13 years of current emissions. There are high uncertainties about the budget. For instance, it may be 100 gigatonnes of CO ₂ equivalent smaller due to CO ₂ and methane release from permafrost and wetlands. However, it is clear that fossil fuel resources need to be proactively kept in the ground to prevent substantial warming. Otherwise, their shortages would not occur until the emissions have already locked in significant long-term impacts.

Causes of recent global temperature rise

Drivers of climate change from 1850-1900 to 2010-2019. There was no significant contribution from internal variability or solar and volcanic drivers.

The climate system experiences various cycles on its own which can last for years, decades or even centuries. For example, El Niño events cause short-term spikes in surface temperature while La Niña events cause short term cooling. Their relative frequency can affect global temperature trends on a decadal timescale. Other changes are caused by an imbalance of energy from external forcings. Examples of these include changes in the concentrations of greenhouse gases, solar luminosity, volcanic eruptions, and variations in the Earth's orbit around the Sun.

To determine the human contribution to climate change, unique "fingerprints" for all potential causes are developed and compared with both observed patterns and known internal climate variability. For example, solar forcing-whose fingerprint involves warming the entire atmosphere-is ruled out because only the lower atmosphere has warmed. Atmospheric aerosols produce a smaller, cooling effect. Other drivers, such as changes in albedo, are less impactful.

Greenhouse gases

CO₂ concentrations over the last 800,000 years as measured from ice cores[99][100][101][102] (blue/green) and directly[103] (black)

Greenhouse gases are transparent to sunlight, and thus allow it to pass through the atmosphere to heat the Earth's surface. The Earth radiates it as heat, and greenhouse gases absorb a portion of it. This absorption slows the rate at which heat escapes into space, trapping heat near the Earth's surface and warming it over time.

While water vapour (≈50%) and clouds (≈25%) are the biggest contributors to the greenhouse effect, they primarily change as a function of temperature and are therefore mostly considered to be feedbacks that change climate sensitivity. On the other hand, concentrations of gases such as CO ₂ (≈20%), tropospheric ozone, CFCs and nitrous oxide are added or removed independently from temperature, and are therefore considered to be external forcings that change global temperatures.

Before the Industrial Revolution, naturally-occurring amounts of greenhouse gases caused the air near the surface to be about 33 °C warmer than it would have been in their absence. Human activity since the Industrial Revolution, mainly extracting and burning fossil fuels ( coal, oil, and natural gas), has increased the amount of greenhouse gases in the atmosphere, resulting in a radiative imbalance. In 2019, the concentrations of CO₂ and methane had increased by about 48% and 160%, respectively, since 1750. These CO ₂ levels are higher than they have been at any time during the last 2 million years. Concentrations of methane are far higher than they were over the last 800,000 years.

The Global Carbon Project shows how additions to CO₂ since 1880 have been caused by different sources ramping up one after another.

Global anthropogenic greenhouse gas emissions in 2019 were equivalent to 59 billion tonnes of CO ₂. Of these emissions, 75% was CO ₂, 18% was methane, 4% was nitrous oxide, and 2% was fluorinated gases. CO ₂ emissions primarily come from burning fossil fuels to provide energy for transport, manufacturing, heating, and electricity. Additional CO ₂ emissions come from deforestation and industrial processes, which include the CO ₂ released by the chemical reactions for making cement, steel, aluminum, and fertiliser. Methane emissions come from livestock, manure, rice cultivation, landfills, wastewater, and coal mining, as well as oil and gas extraction. Nitrous oxide emissions largely come from the microbial decomposition of fertiliser.

While methane only lasts in the atmosphere for an average of 12 years, CO ₂ lasts much longer. The Earth's surface absorbs CO2 as part of the carbon cycle. While plants on land and in the ocean absorb most excess emissions of CO ₂ every year, that CO ₂ is returned to the atmosphere when biological matter is digested, burns, or decays. Land-surface carbon sink processes, such as carbon fixation in the soil and photosynthesis, remove about 29% of annual global CO ₂ emissions. The ocean has absorbed 20 to 30% of emitted CO ₂ over the last 2 decades. CO ₂ is only removed from the atmosphere for the long term when it is stored in the Earth's crust, which is a process that can take millions of years to complete.

Land surface changes

According to Food and Agriculture Organization, around 30% of Earth's land area is largely unusable for humans ( glaciers, deserts, etc.), 26% is forests, 10% is shrubland and 34% is agricultural land. Deforestation is the main land use change contributor to global warming, as the destroyed trees release CO ₂, and are not replaced by new trees, removing that carbon sink. Between 2001 and 2018, 27% of deforestation was from permanent clearing to enable agricultural expansion for crops and livestock. Another 24% has been lost to temporary clearing under the shifting cultivation agricultural systems. 26% was due to logging for wood and derived products, and wildfires have accounted for the remaining 23%. Some forests have not been fully cleared, but were already degraded by these impacts. Restoring these forests also recovers their potential as a carbon sink.

Local vegetation cover impacts how much of the sunlight gets reflected back into space ( albedo), and how much heat is lost by evaporation. For instance, the change from a dark forest to grassland makes the surface lighter, causing it to reflect more sunlight. Deforestation can also modify the release of chemical compounds that influence clouds, and by changing wind patterns. In tropic and temperate areas the net effect is to produce significant warming, and forest restoration can make local temperatures cooler. At latitudes closer to the poles, there is a cooling effect as forest is replaced by snow-covered (and more reflective) plains. Globally, these increases in surface albedo have been the dominant direct influence on temperature from land use change. Thus, land use change to date is estimated to have a slight cooling effect.

Other factors

Aerosols and clouds

Air pollution, in the form of aerosols, affects the climate on a large scale. Aerosols scatter and absorb solar radiation. From 1961 to 1990, a gradual reduction in the amount of sunlight reaching the Earth's surface was observed. This phenomenon is popularly known as global dimming, and is primarily attributed to sulfate aerosols produced by the combustion of fossil fuels with heavy sulfur concentrations like coal and bunker fuel. Smaller contributions come from black carbon, organic carbon from combustion of fossil fuels and biofuels, and from anthropogenic dust. Globally, aerosols have been declining since 1990 due to pollution controls, meaning that they no longer mask greenhouse gas warming as much.

Aerosols also have indirect effects on the Earth's energy budget. Sulfate aerosols act as cloud condensation nuclei and lead to clouds that have more and smaller cloud droplets. These clouds reflect solar radiation more efficiently than clouds with fewer and larger droplets. They also reduce the growth of raindrops, which makes clouds more reflective to incoming sunlight. Indirect effects of aerosols are the largest uncertainty in radiative forcing.

While aerosols typically limit global warming by reflecting sunlight, black carbon in soot that falls on snow or ice can contribute to global warming. Not only does this increase the absorption of sunlight, it also increases melting and sea-level rise. Limiting new black carbon deposits in the Arctic could reduce global warming by 0.2 °C by 2050. The effect of decreasing sulfur content of fuel oil for ships since 2020 is estimated to cause an additional 0.05 °C increase in global mean temperature by 2050.

Solar and volcanic activity

The Fourth National Climate Assessment ("NCA4", USGCRP, 2017) includes charts illustrating that neither solar nor volcanic activity can explain the observed warming.[141][142]

As the Sun is the Earth's primary energy source, changes in incoming sunlight directly affect the climate system. Solar irradiance has been measured directly by satellites, and indirect measurements are available from the early 1600s onwards. Since 1880, there has been no upward trend in the amount of the Sun's energy reaching the Earth, in contrast to the warming of the lower atmosphere (the troposphere). The upper atmosphere (the stratosphere) would also be warming if the Sun was sending more energy to Earth, but instead, it has been cooling. This is consistent with greenhouse gases preventing heat from leaving the Earth's atmosphere.

Explosive volcanic eruptions can release gases, dust and ash that partially block sunlight and reduce temperatures, or they can send water vapor into the atmosphere, which adds to greenhouse gases and increases temperatures. These impacts on temperature only last for several years, because both water vapor and volcanic material have low persistence in the atmosphere. volcanic CO₂ emissions are more persistent, but they are equivalent to less than 1% of current human-caused CO ₂ emissions. Volcanic activity still represents the single largest natural impact (forcing) on temperature in the industrial era. Yet, like the other natural forcings, it has had negligible impacts on global temperature trends since the Industrial Revolution.

Climate change feedbacks

Sea ice reflects 50% to 70% of incoming sunlight, while the ocean, being darker, reflects only 6%. As an area of sea ice melts and exposes more ocean, more heat is absorbed by the ocean, raising temperatures that melt still more ice. This is a positive feedback process.[149]

The response of the climate system to an initial forcing is modified by feedbacks: increased by "self-reinforcing" or "positive" feedbacks and reduced by "balancing" or "negative" feedbacks. The main reinforcing feedbacks are the water-vapour feedback, the ice-albedo feedback, and the net effect of clouds. The primary balancing mechanism is radiative cooling, as Earth's surface gives off more heat to space in response to rising temperature. In addition to temperature feedbacks, there are feedbacks in the carbon cycle, such as the fertilising effect of CO ₂ on plant growth. Feedbacks are expected to trend in a positive direction as greenhouse gas emissions continue, raising climate sensitivty.

Radiative feedbacks are physical processes that influence the rate of global warming in response to warming. For instance, warmer air can hold more moisture, and water vapour itself is a potent greenhouse gas. Warmer air can also result in clouds becoming higher and thinner, where they act as an insulator and warm the planet. Another major feedback is the reduction of snow cover and sea ice in the Arctic, reducing the reflectivity of the Earth's surface there and contributing to amplification of Arctic temperature changes. Arctic amplification is also thawing permafrost, which releases methane and CO ₂ into the atmosphere.

Around half of human-caused CO ₂ emissions have been absorbed by land plants and by the oceans. This fraction is not static and if future CO ₂ emissions decrease, the Earth will be able to absorb up to around 70%. If they increase substantially, it'll still absorb more carbon than now, but the overall fraction will decrease to below 40%. This is because climate change increases droughts and heat waves that eventually inhibit plant growth on land, and soils will release more carbon from dead plants when they are warmer. The rate at which oceans absorb atmospheric carbon will be lowered as they become more acidic and experience changes in thermohaline circulation and phytoplankton distribution. Uncertainty over feedbacks, particularly cloud cover, is the major reason why different climate models project different magnitudes of warming for a given amount of emissions.

Energy flows between space, the atmosphere, and Earth's surface. Most sunlight passes through the atmosphere to heat the Earth's surface, then greenhouse gases absorb most of the heat the Earth radiates in response. Adding to greenhouse gases increases this insulating effect, causing an energy imbalance that heats the planet up.

A climate model is a representation of the physical, chemical and biological processes that affect the climate system. Models include natural processes like changes in the Earth's orbit, historical changes in the Sun's activity, and volcanic forcing. Models are used to estimate the degree of warming future emissions will cause when accounting for the strength of climate feedbacks. Models also predict the circulation of the oceans, the annual cycle of the seasons, and the flows of carbon between the land surface and the atmosphere.

The physical realism of models is tested by examining their ability to simulate contemporary or past climates. Past models have underestimated the rate of Arctic shrinkage and underestimated the rate of precipitation increase. Sea level rise since 1990 was underestimated in older models, but more recent models agree well with observations. The 2017 United States-published National Climate Assessment notes that "climate models may still be underestimating or missing relevant feedback processes". Additionally, climate models may be unable to adequately predict short-term regional climatic shifts.

A subset of climate models add societal factors to a physical climate model. These models simulate how population, economic growth, and energy use affect-and interact with-the physical climate. With this information, these models can produce scenarios of future greenhouse gas emissions. This is then used as input for physical climate models and carbon cycle models to predict how atmospheric concentrations of greenhouse gases might change. Depending on the socioeconomic scenario and the mitigation scenario, models produce atmospheric CO ₂ concentrations that range widely between 380 and 1400 ppm.

The sixth IPCC Assessment Report projects changes in average soil moisture at 2.0 °C of warming, as measured in standard deviations from the 1850 to 1900 baseline.

Environmental effects

The environmental effects of climate change are broad and far-reaching, affecting oceans, ice, and weather. Changes may occur gradually or rapidly. Evidence for these effects comes from studying climate change in the past, from modelling, and from modern observations. Since the 1950s, droughts and heat waves have appeared simultaneously with increasing frequency. Extremely wet or dry events within the monsoon period have increased in India and East Asia. Monsoonal precipitation over the Northern Hemisphere has increased since 1980. The rainfall rate and intensity of hurricanes and typhoons is likely increasing, and the geographic range likely expanding poleward in response to climate warming. Frequency of tropical cyclones has not increased as a result of climate change.

Global sea level is rising as a consequence of thermal expansion and the melting of glaciers and ice sheets. Between 1993 and 2020, the rise increased over time, averaging 3.3 ± 0.3 mm per year. Over the 21st century, the IPCC projects 32-62 cm of sea level rise under a low emission scenario, 44-76 cm under an intermediate one and 65-101 cm under a very high emission scenario. Marine ice sheet instability processes in Antarctica may add substantially to these values, including the possibility of a 2-meter sea level rise by 2100 under high emissions.

Climate change has led to decades of shrinking and thinning of the Arctic sea ice. While ice-free summers are expected to be rare at 1.5 °C degrees of warming, they are set to occur once every three to ten years at a warming level of 2 °C. Higher atmospheric CO ₂ concentrations cause more CO ₂ to dissolve in the oceans, which is making them more acidic. Because oxygen is less soluble in warmer water, its concentrations in the ocean are decreasing, and dead zones are expanding.

Tipping points and long-term impacts

Different levels of global warming may cause different parts of Earth's climate system to reach tipping points that cause transitions to different states.[199][200]

Greater degrees of global warming increase the risk of passing through ' tipping points'-thresholds beyond which certain major impacts can no longer be avoided even if temperatures return to their previous state. For instance, the Greenland ice sheet is already melting, but if global warming reaches levels between 1.7 °C and 2.3 °C, its melting will continue until it fully disappears. If the warming is later reduced to 1.5 °C or less, it will still lose a lot more ice than if the warming was never allowed to reach the threshold in the first place. While the ice sheets would melt over millennia, other tipping points would occur faster and give societies less time to respond. The collapse of major ocean currents like the Atlantic meridional overturning circulation (AMOC), and irreversible damage to key ecosystems like the Amazon rainforest and coral reefs can unfold in a matter of decades.

The long-term effects of climate change on oceans include further ice melt, ocean warming, sea level rise, ocean acidification and ocean deoxygenation. The timescale of long-term impacts are centuries to millennia due to CO ₂'s long atmospheric lifetime. When net emissions stabilise surface air temperatures will also stabilise, but oceans and ice caps will continue to absorb excess heat from the atmosphere. The result is an estimated total sea level rise of 2.3 metres per degree Celsius (4.2 ft/°F) after 2000 years. Oceanic CO ₂ uptake is slow enough that ocean acidification will also continue for hundreds to thousands of years. Deep oceans (below 2,000 metres (6,600 ft)) are also already committed to losing over 10% of their dissolved oxygen by the warming which occurred to date. Further, the West Antarctic ice sheet appears committed to practically irreversible melting, which would increase the sea levels by at least 3.3 m (10 ft 10 in) over approximately 2000 years.

Nature and wildlife

Recent warming has driven many terrestrial and freshwater species poleward and towards higher altitudes. For instance, the range of hundreds of North American birds has shifted northward at an average rate of 1.5 km/year over the past 55 years. Higher atmospheric CO ₂ levels and an extended growing season have resulted in global greening. However, heatwaves and drought have reduced ecosystem productivity in some regions. The future balance of these opposing effects is unclear. A related phenomenon driven by climate change is woody plant encroachment, affecting up to 500 million hectares globally. Climate change has contributed to the expansion of drier climate zones, such as the expansion of deserts in the subtropics. The size and speed of global warming is making abrupt changes in ecosystems more likely. Overall, it is expected that climate change will result in the extinction of many species.

The oceans have heated more slowly than the land, but plants and animals in the ocean have migrated towards the colder poles faster than species on land. Just as on land, heat waves in the ocean occur more frequently due to climate change, harming a wide range of organisms such as corals, kelp, and seabirds. Ocean acidification makes it harder for marine calcifying organisms such as mussels, barnacles and corals to produce shells and skeletons; and heatwaves have bleached coral reefs. Harmful algal blooms enhanced by climate change and eutrophication lower oxygen levels, disrupt food webs and cause great loss of marine life. Coastal ecosystems are under particular stress. Almost half of global wetlands have disappeared due to climate change and other human impacts. Plants have come under increased stress from damage by insects.

The effects of climate change are impacting humans everywhere in the world. Impacts can be observed on all continents and ocean regions, with low-latitude, less developed areas facing the greatest risk. Continued warming has potentially "severe, pervasive and irreversible impacts" for people and ecosystems. The risks are unevenly distributed, but are generally greater for disadvantaged people in developing and developed countries.

Food and health

The World Health Organization (WHO) calls climate change the greatest threat to global health in the 21st century. Extreme weather leads to injury and loss of life. Various infectious diseases are more easily transmitted in a warmer climate, such as dengue fever and malaria. Crop failures can lead to food shortages and malnutrition, particularly effecting children. Both children and older people are vulnerable to extreme heat. The WHO has estimated that between 2030 and 2050, climate change would cause around 250,000 additional deaths per year. They assessed deaths from heat exposure in elderly people, increases in diarrhea, malaria, dengue, coastal flooding, and childhood malnutrition. By 2100, 50% to 75% of the global population may face climate conditions that are life-threatening due to combined effects of extreme heat and humidity.

Climate change is affecting food security. It has caused reduction in global yields of maize, wheat, and soybeans between 1981 and 2010. Future warming could further reduce global yields of major crops. Crop production will probably be negatively affected in low-latitude countries, while effects at northern latitudes may be positive or negative. Up to an additional 183 million people worldwide, particularly those with lower incomes, are at risk of hunger as a consequence of these impacts. Climate change also impacts fish populations. Globally, less will be available to be fished. Regions dependent on glacier water, regions that are already dry, and small islands have a higher risk of water stress due to climate change.

Livelihoods and inequality

Economic damages due to climate change may be severe and there is a chance of disastrous consequences. Severe impacts are expected in South-East Asia and sub-Saharan Africa, where most of the local inhabitants are dependent upon natural and agricultural resources. Heat stress can prevent outdoor labourers from working. If warming reaches 4 °C then labour capacity in those regions could be reduced by 30 to 50%. The World Bank estimates that between 2016 and 2030, climate change could drive over 120 million people into extreme poverty without adaptation.

Inequalities based on wealth and social status have worsened due to climate change. Major difficulties in mitigating, adapting to, and recovering from climate shocks are faced by marginalised people who have less control over resources. Indigenous people, who are subsistent on their land and ecosystems, will face endangerment to their wellness and lifestyles due to climate change. An expert elicitation concluded that the role of climate change in armed conflict has been small compared to factors such as socio-economic inequality and state capabilities.

While women are not inherently more at risk from climate change and shocks, limits on women's resources and discriminatory gender norms constrain their adaptive capacity and resilience. For example, women's work burdens, including hours worked in agriculture, tend to decline less than men's during climate shocks such as heat stress.

Climate migration

Low-lying islands and coastal communities are threatened by sea level rise, which makes urban flooding more common. Sometimes, land is permanently lost to the sea. This could lead to statelessness for people in island nations, such as the Maldives and Tuvalu. In some regions, the rise in temperature and humidity may be too severe for humans to adapt to. With worst-case climate change, models project that almost one-third of humanity might live in Sahara-like uninhabitable and extremely hot climates.

These factors can drive climate or environmental migration, within and between countries. More people are expected to be displaced because of sea level rise, extreme weather and conflict from increased competition over natural resources. Climate change may also increase vulnerability, leading to "trapped populations" who are not able to move due to a lack of resources.

Reducing and recapturing emissions

Global greenhouse gas emission scenarios, based on policies and pledges as of November 2021

Climate change can be mitigated by reducing the rate at which greenhouse gases are emitted into the atmosphere, and by increasing the rate at which carbon dioxide is removed from the atmosphere. In order to limit global warming to less than 1.5 °C global greenhouse gas emissions needs to be net-zero by 2050, or by 2070 with a 2 °C target. This requires far-reaching, systemic changes on an unprecedented scale in energy, land, cities, transport, buildings, and industry.

The United Nations Environment Programme estimates that countries need to triple their pledges under the Paris Agreement within the next decade to limit global warming to 2 °C. An even greater level of reduction is required to meet the 1.5 °C goal. With pledges made under the Paris Agreement as of October 2021, global warming would still have a 66% chance of reaching about 2.7 °C (range: 2.2-3.2 °C) by the end of the century. Globally, limiting warming to 2 °C may result in higher economic benefits than economic costs.

Although there is no single pathway to limit global warming to 1.5 or 2 °C, most scenarios and strategies see a major increase in the use of renewable energy in combination with increased energy efficiency measures to generate the needed greenhouse gas reductions. To reduce pressures on ecosystems and enhance their carbon sequestration capabilities, changes would also be necessary in agriculture and forestry, such as preventing deforestation and restoring natural ecosystems by reforestation.

Other approaches to mitigating climate change have a higher level of risk. Scenarios that limit global warming to 1.5 °C typically project the large-scale use of carbon dioxide removal methods over the 21st century. There are concerns, though, about over-reliance on these technologies, and environmental impacts. Solar radiation modification (SRM) is also a possible supplement to deep reductions in emissions. However, SRM raises significant ethical and legal concerns, and the risks are imperfectly understood.

Clean energy

Coal, oil, and natural gas remain the primary global energy sources even as renewables have begun rapidly increasing.[278]

Wind and solar power, Germany

Renewable energy is key to limiting climate change. For decades, fossil fuels have accounted for roughly 80% of the world's energy use. The remaining share has been split between nuclear power and renewables (including hydropower, bioenergy, wind and solar power and geothermal energy). Fossil fuel use is expected to peak in absolute terms prior to 2030 and then to decline, with coal use experiencing the sharpest reductions. Renewables represented 75% of all new electricity generation installed in 2019, nearly all solar and wind. Other forms of clean energy, such as nuclear and hydropower, currently have a larger share of the energy supply. However, their future growth forecasts appear limited in comparison.

While solar panels and onshore wind are now among the cheapest forms of adding new power generation capacity in many locations, green energy policies are needed to achieve a rapid transition from fossil fuels to renewables. To achieve carbon neutrality by 2050, renewable energy would become the dominant form of electricity generation, rising to 85% or more by 2050 in some scenarios. Investment in coal would be eliminated and coal use nearly phased out by 2050.

Electricity generated from renewable sources would also need to become the main energy source for heating and transport. Transport can switch away from internal combustion engine vehicles and towards electric vehicles, public transit, and active transport (cycling and walking). For shipping and flying, low-carbon fuels would reduce emissions. Heating could be increasingly decarbonised with technologies like heat pumps.

There are obstacles to the continued rapid growth of clean energy, including renewables. For wind and solar, there are environmental and land use concerns for new projects. Wind and solar also produce energy intermittently and with seasonal variability. Traditionally, hydro dams with reservoirs and conventional power plants have been used when variable energy production is low. Going forward, battery storage can be expanded, energy demand and supply can be matched, and long-distance transmission can smooth variability of renewable outputs. Bioenergy is often not carbon-neutral and may have negative consequences for food security. The growth of nuclear power is constrained by controversy around radioactive waste, nuclear weapon proliferation, and accidents. Hydropower growth is limited by the fact that the best sites have been developed, and new projects are confronting increased social and environmental concerns.

Low-carbon energy improves human health by minimising climate change as well as reducing air pollution deaths, which were estimated at 7 million annually in 2016. Meeting the Paris Agreement goals that limit warming to a 2 °C increase could save about a million of those lives per year by 2050, whereas limiting global warming to 1.5 °C could save millions and simultaneously increase energy security and reduce poverty. Improving air quality also has economic benefits which may be larger than mitigation costs.

Energy conservation

Reducing energy demand is another major aspect of reducing emissions. If less energy is needed, there is more flexibility for clean energy development. It also makes it easier to manage the electricity grid, and minimises carbon-intensive infrastructure development. Major increases in energy efficiency investment will be required to achieve climate goals, comparable to the level of investment in renewable energy. Several COVID-19 related changes in energy use patterns, energy efficiency investments, and funding have made forecasts for this decade more difficult and uncertain.

Strategies to reduce energy demand vary by sector. In the transport sector, passengers and freight can switch to more efficient travel modes, such as buses and trains, or use electric vehicles. Industrial strategies to reduce energy demand include improving heating systems and motors, designing less energy-intensive products, and increasing product lifetimes. In the building sector the focus is on better design of new buildings, and higher levels of energy efficiency in retrofitting. The use of technologies like heat pumps can also increase building energy efficiency.

Agriculture and industry

Taking into account direct and indirect emissions, industry is the sector with the highest share of global emissions. Data as of 2019 from the IPCC.

Agriculture and forestry face a triple challenge of limiting greenhouse gas emissions, preventing the further conversion of forests to agricultural land, and meeting increases in world food demand. A set of actions could reduce agriculture and forestry-based emissions by two thirds from 2010 levels. These include reducing growth in demand for food and other agricultural products, increasing land productivity, protecting and restoring forests, and reducing greenhouse gas emissions from agricultural production.

On the demand side, a key component of reducing emissions is shifting people towards plant-based diets. Eliminating the production of livestock for meat and dairy would eliminate about 3/4ths of all emissions from agriculture and other land use. Livestock also occupy 37% of ice-free land area on Earth and consume feed from the 12% of land area used for crops, driving deforestation and land degradation.

Steel and cement production are responsible for about 13% of industrial CO ₂ emissions. In these industries, carbon-intensive materials such as coke and lime play an integral role in the production, so that reducing CO ₂ emissions requires research into alternative chemistries.

Carbon sequestration

Most CO₂ emissions have been absorbed by carbon sinks, including plant growth, soil uptake, and ocean uptake (2020 Global Carbon Budget).

Natural carbon sinks can be enhanced to sequester significantly larger amounts of CO ₂ beyond naturally occurring levels. Reforestation and afforestation (planting forests where there were none before) are among the most mature sequestration techniques, although the latter raises food security concerns. Farmers can promote sequestration of carbon in soils through practices such as use of winter cover crops, reducing the intensity and frequency of tillage, and using compost and manure as soil amendments. Forest and landscape restoration yields many benefits for the climate, including greenhouse gas emissions sequestration and reduction. Restoration/recreation of coastal wetlands, prairie plots and seagrass meadows increases the uptake of carbon into organic matter. When carbon is sequestered in soils and in organic matter such as trees, there is a risk of the carbon being re-released into the atmosphere later through changes in land use, fire, or other changes in ecosystems.

Where energy production or CO ₂-intensive heavy industries continue to produce waste CO ₂, the gas can be captured and stored instead of released to the atmosphere. Although its current use is limited in scale and expensive, carbon capture and storage (CCS) may be able to play a significant role in limiting CO ₂ emissions by mid-century. This technique, in combination with bioenergy ( BECCS) can result in net negative emissions as CO ₂ is drawn from the atmosphere. It remains highly uncertain whether carbon dioxide removal techniques will be able to play a large role in limiting warming to 1.5 °C. Policy decisions that rely on carbon dioxide removal increase the risk of global warming rising beyond international goals.

Adaptation

Adaptation is "the process of adjustment to current or expected changes in climate and its effects". Without additional mitigation, adaptation cannot avert the risk of "severe, widespread and irreversible" impacts. More severe climate change requires more transformative adaptation, which can be prohibitively expensive. The capacity and potential for humans to adapt is unevenly distributed across different regions and populations, and developing countries generally have less. The first two decades of the 21st century saw an increase in adaptive capacity in most low- and middle-income countries with improved access to basic sanitation and electricity, but progress is slow. Many countries have implemented adaptation policies. However, there is a considerable gap between necessary and available finance.

Adaptation to sea level rise consists of avoiding at-risk areas, learning to live with increased flooding, and building flood controls. If that fails, managed retreat may be needed. There are economic barriers for tackling dangerous heat impact. Avoiding strenuous work or having air conditioning is not possible for everybody. In agriculture, adaptation options include a switch to more sustainable diets, diversification, erosion control, and genetic improvements for increased tolerance to a changing climate. Insurance allows for risk-sharing, but is often difficult to get for people on lower incomes. Education, migration and early warning systems can reduce climate vulnerability. Planting mangroves or encouraging other coastal vegetation can buffer storms.

Ecosystems adapt to climate change, a process that can be supported by human intervention. By increasing connectivity between ecosystems, species can migrate to more favourable climate conditions. Species can also be introduced to areas acquiring a favorable climate. Protection and restoration of natural and semi-natural areas helps build resilience, making it easier for ecosystems to adapt. Many of the actions that promote adaptation in ecosystems, also help humans adapt via ecosystem-based adaptation. For instance, restoration of natural fire regimes makes catastrophic fires less likely, and reduces human exposure. Giving rivers more space allows for more water storage in the natural system, reducing flood risk. Restored forest acts as a carbon sink, but planting trees in unsuitable regions can exacerbate climate impacts.

There are synergies but also trade-offs between adaptation and mitigation. An example for synergy is increased food productivity, which has large benefits for both adaptation and mitigation. An example of a trade-off is that increased use of air conditioning allows people to better cope with heat, but increases energy demand. Another trade-off example is that more compact urban development may reduce emissions from transport and construction, but may also increase the urban heat island effect, exposing people to heat-related health risks.

Policies and politics

The Climate Change Performance Index ranks countries by greenhouse gas emissions (40% of score), renewable energy (20%), energy use (20%), and climate policy (20%).

Countries that are most vulnerable to climate change have typically been responsible for a small share of global emissions. This raises questions about justice and fairness. Limiting global warming makes it much easier to achieve the UN's Sustainable Development Goals, such as eradicating poverty and reducing inequalities. The connection is recognised in Sustainable Development Goal 13 which is to "take urgent action to combat climate change and its impacts". The goals on food, clean water and ecosystem protection have synergies with climate mitigation.

The geopolitics of climate change is complex. It has often been framed as a free-rider problem, in which all countries benefit from mitigation done by other countries, but individual countries would lose from switching to a low-carbon economy themselves. Sometimes mitigation also has localised benefits though. For instance, the benefits of a coal phase-out to public health and local environments exceed the costs in almost all regions. Furthermore, net importers of fossil fuels win economically from switching to clean energy, causing net exporters to face stranded assets: fossil fuels they cannot sell.

Policy options

A wide range of policies, regulations, and laws are being used to reduce emissions. As of 2019, carbon pricing covers about 20% of global greenhouse gas emissions. Carbon can be priced with carbon taxes and emissions trading systems. Direct global fossil fuel subsidies reached $319 billion in 2017, and $5.2 trillion when indirect costs such as air pollution are priced in. Ending these can cause a 28% reduction in global carbon emissions and a 46% reduction in air pollution deaths. Money saved on fossil subsidies could be used to support the transition to clean energy instead. More direct methods to reduce greenhouse gases include vehicle efficiency standards, renewable fuel standards, and air pollution regulations on heavy industry. Several countries require utilities to increase the share of renewables in power production.

Climate justice

Policy designed through the lens of climate justice tries to address human rights issues and social inequality. According to proponents of climate justice, the costs of climate adaptation should be paid by those most responsible for climate change, while the beneficiaries of payments should be those suffering impacts. One way this can be addressed in practice is to have wealthy nations pay poorer countries to adapt.

Oxfam found that in 2023 the wealthiest 10% of people were responsible for 50% of global emissions, while the bottom 50% were responsible for just 8%. Production of emissions is another way to look at responsibility: under that approach, the top 21 fossil fuel companies would owe cumulative climate reparations of $5.4 trillion over the period 2025-2050. To achieve a just transition, people working in the fossil fuel sector would also need other jobs, and their communities would need investments.

International climate agreements

Since 2000, rising CO₂ emissions in China and the rest of world have surpassed the output of the United States and Europe.[358]

Per person, the United States generates CO₂ at a far faster rate than other primary regions.[358]

Nearly all countries in the world are parties to the 1994 United Nations Framework Convention on Climate Change (UNFCCC). The goal of the UNFCCC is to prevent dangerous human interference with the climate system. As stated in the convention, this requires that greenhouse gas concentrations are stabilised in the atmosphere at a level where ecosystems can adapt naturally to climate change, food production is not threatened, and economic development can be sustained. The UNFCCC does not itself restrict emissions but rather provides a framework for protocols that do. Global emissions have risen since the UNFCCC was signed. Its yearly conferences are the stage of global negotiations.

The 1997 Kyoto Protocol extended the UNFCCC and included legally binding commitments for most developed countries to limit their emissions. During the negotiations, the G77 (representing developing countries) pushed for a mandate requiring developed countries to "[take] the lead" in reducing their emissions, since developed countries contributed most to the accumulation of greenhouse gases in the atmosphere. Per-capita emissions were also still relatively low in developing countries and developing countries would need to emit more to meet their development needs.

The 2009 Copenhagen Accord has been widely portrayed as disappointing because of its low goals, and was rejected by poorer nations including the G77. Associated parties aimed to limit the global temperature rise to below 2 °C. The Accord set the goal of sending $100 billion per year to developing countries for mitigation and adaptation by 2020, and proposed the founding of the Green Climate Fund. As of 2020, only 83.3 billion were delivered. Only in 2023 the target is expected to be achieved.

In 2015 all UN countries negotiated the Paris Agreement, which aims to keep global warming well below 2.0 °C and contains an aspirational goal of keeping warming under 1.5 °C. The agreement replaced the Kyoto Protocol. Unlike Kyoto, no binding emission targets were set in the Paris Agreement. Instead, a set of procedures was made binding. Countries have to regularly set ever more ambitious goals and reevaluate these goals every five years. The Paris Agreement restated that developing countries must be financially supported. As of October 2021, 194 states and the European Union have signed the treaty and 191 states and the EU have ratified or acceded to the agreement.

The 1987 Montreal Protocol, an international agreement to stop emitting ozone-depleting gases, may have been more effective at curbing greenhouse gas emissions than the Kyoto Protocol specifically designed to do so. The 2016 Kigali Amendment to the Montreal Protocol aims to reduce the emissions of hydrofluorocarbons, a group of powerful greenhouse gases which served as a replacement for banned ozone-depleting gases. This made the Montreal Protocol a stronger agreement against climate change.

National responses

In 2019, the United Kingdom parliament became the first national government to declare a climate emergency. Other countries and jurisdictions followed suit. That same year, the European Parliament declared a "climate and environmental emergency". The European Commission presented its European Green Deal with the goal of making the EU carbon-neutral by 2050. In 2021, the European Commission released its " Fit for 55" legislation package, which contains guidelines for the car industry; all new cars on the European market must be zero-emission vehicles from 2035.

Major countries in Asia have made similar pledges: South Korea and Japan have committed to become carbon-neutral by 2050, and China by 2060. While India has strong incentives for renewables, it also plans a significant expansion of coal in the country. Vietnam is among very few coal-dependent, fast-developing countries that pledged to phase out unabated coal power by the 2040s or as soon as possible thereafter.

As of 2021, based on information from 48 national climate plans, which represent 40% of the parties to the Paris Agreement, estimated total greenhouse gas emissions will be 0.5% lower compared to 2010 levels, below the 45% or 25% reduction goals to limit global warming to 1.5 °C or 2 °C, respectively.

Denial and misinformation

Data has been cherry picked from short periods to falsely assert that global temperatures are not rising. Blue trendlines show short periods that mask longer-term warming trends (red trendlines). Blue rectangle with blue dots shows the so-called global warming hiatus.

Public debate about climate change has been strongly affected by climate change denial and misinformation, which originated in the United States and has since spread to other countries, particularly Canada and Australia. Climate change denial has originated from fossil fuel companies, industry groups, conservative think tanks, and contrarian scientists. Like the tobacco industry, the main strategy of these groups has been to manufacture doubt about climate-change related scientific data and results. People who hold unwarranted doubt about climate change are called climate change "skeptics", although "contrarians" or "deniers" are more appropriate terms.

There are different variants of climate denial: some deny that warming takes place at all, some acknowledge warming but attribute it to natural influences, and some minimise the negative impacts of climate change. Manufacturing uncertainty about the science later developed into a manufactured controversy: creating the belief that there is significant uncertainty about climate change within the scientific community in order to delay policy changes. Strategies to promote these ideas include criticism of scientific institutions, and questioning the motives of individual scientists. An echo chamber of climate-denying blogs and media has further fomented misunderstanding of climate change.

Public awareness and opinion

The public substantially underestimates the degree of scientific consensus that humans are causing climate change.[394] Studies from 2019 to 2021[395][4][396] found scientific consensus to range from 98.7 to 100%.

Climate change came to international public attention in the late 1980s. Due to media coverage in the early 1990s, people often confused climate change with other environmental issues like ozone depletion. In popular culture, the climate fiction movie The Day After Tomorrow (2004) and the Al Gore documentary An Inconvenient Truth (2006) focused on climate change.

Significant regional, gender, age and political differences exist in both public concern for, and understanding of, climate change. More highly educated people, and in some countries, women and younger people, were more likely to see climate change as a serious threat. Partisan gaps also exist in many countries, and countries with high CO ₂ emissions tend to be less concerned. Views on causes of climate change vary widely between countries. Concern has increased over time, to the point where in 2021 a majority of citizens in many countries express a high level of worry about climate change, or view it as a global emergency. Higher levels of worry are associated with stronger public support for policies that address climate change.

Climate movement

Climate protests demand that political leaders take action to prevent climate change. They can take the form of public demonstrations, fossil fuel divestment, lawsuits and other activities. Prominent demonstrations include the School Strike for Climate. In this initiative, young people across the globe have been protesting since 2018 by skipping school on Fridays, inspired by Swedish teenager Greta Thunberg. Mass civil disobedience actions by groups like Extinction Rebellion have protested by disrupting roads and public transport.

Litigation is increasingly used as a tool to strengthen climate action from public institutions and companies. Activists also initiate lawsuits which target governments and demand that they take ambitious action or enforce existing laws on climate change. Lawsuits against fossil-fuel companies generally seek compensation for loss and damage.

Early discoveries

Scientists in the 19th century such as Alexander von Humboldt began to foresee the effects of climate change. In the 1820s, Joseph Fourier proposed the greenhouse effect to explain why Earth's temperature was higher than the Sun's energy alone could explain. Earth's atmosphere is transparent to sunlight, so sunlight reaches the surface where it is converted to heat. However, the atmosphere is not transparent to heat radiating from the surface, and captures some of that heat, which in turn warms the planet.

In 1856 Eunice Newton Foote demonstrated that the warming effect of the Sun is greater for air with water vapour than for dry air, and that the effect is even greater with carbon dioxide (CO ₂). She concluded that "An atmosphere of that gas would give to our earth a high temperature..."

Studying what would become known as the greenhouse effect, Tyndall's pre-1861 ratio spectrophotometer measured how much various gases in a tube absorb and emit infrared radiation-which humans experience as heat.

Starting in 1859, John Tyndall established that nitrogen and oxygen-together totaling 99% of dry air-are transparent to radiated heat. However, water vapour and gases such as methane and carbon dioxide absorb radiated heat and re-radiate that heat into the atmosphere. Tyndall proposed that changes in the concentrations of these gases may have caused climatic changes in the past, including ice ages.

Svante Arrhenius noted that water vapour in air continuously varied, but the CO ₂ concentration in air was influenced by long-term geological processes. Warming from increased CO ₂ levels would increase the amount of water vapour, amplifying warming in a positive feedback loop. In 1896, he published the first climate model of its kind, projecting that halving CO ₂ levels could have produced a drop in temperature initiating an ice age. Arrhenius calculated the temperature increase expected from doubling CO ₂ to be around 5-6 °C. Other scientists were initially skeptical and believed that the greenhouse effect was saturated so that adding more CO ₂ would make no difference, and that the climate would be self-regulating. Beginning in 1938, Guy Stewart Callendar published evidence that climate was warming and CO ₂ levels were rising, but his calculations met the same objections.

Development of a scientific consensus

Scientific consensus on causation: Academic studies of scientific agreement on human-caused global warming among climate experts (2010-2015) reflect that the level of consensus correlates with expertise in climate science.[423] A 2019 study found scientific consensus to be at 100%,[424] and a 2021 study concluded that consensus exceeded 99%.[425] Another 2021 study found that 98.7% of climate experts indicated that the Earth is getting warmer mostly because of human activity.[426]

In the 1950s, Gilbert Plass created a detailed computer model that included different atmospheric layers and the infrared spectrum. This model predicted that increasing CO ₂ levels would cause warming. Around the same time, Hans Suess found evidence that CO ₂ levels had been rising, and Roger Revelle showed that the oceans would not absorb the increase. The two scientists subsequently helped Charles Keeling to begin a record of continued increase, which has been termed the " Keeling Curve". Scientists alerted the public, and the dangers were highlighted at James Hansen's 1988 Congressional testimony. The Intergovernmental Panel on Climate Change (IPCC), set up in 1988 to provide formal advice to the world's governments, spurred interdisciplinary research. As part of the IPCC reports, scientists assess the scientific discussion that takes place in peer-reviewed journal articles.

There is a near-complete scientific consensus that the climate is warming and that this is caused by human activities. As of 2019, agreement in recent literature reached over 99%. No scientific body of national or international standing disagrees with this view. Consensus has further developed that some form of action should be taken to protect people against the impacts of climate change. National science academies have called on world leaders to cut global emissions. The 2021 IPCC Assessment Report stated that it is "unequivocal" that climate change is caused by humans.

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This article incorporates text from a free content work. Licensed under CC BY-SA 3.0 ( license statement/permission). Text taken from The status of women in agrifood systems - Overview​, FAO, FAO.

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Fifth Assessment report

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IPCC (2014). Edenhofer, O.; Pichs-Madruga, R.; Sokona, Y.; Farahani, E.; et al. (eds.). Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK & New York, NY: Cambridge University Press. ISBN 978-1-107-05821-7.

IPCC AR5 SYR (2014). The Core Writing Team; Pachauri, R. K.; Meyer, L. A. (eds.). Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Geneva, Switzerland: IPCC.

Special Report: Global Warming of 1.5 °C

Special Report: Climate change and Land

Special Report: The Ocean and Cryosphere in a Changing Climate

Sixth Assessment Report

IPCC (2021). Masson-Delmotte, V.; Zhai, P.; Pirani, A.; Connors, S. L.; et al. (eds.). Climate Change 2021: The Physical Science Basis (PDF). Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, United Kingdom and New York, NY, US: Cambridge University Press (In Press).

IPCC (2022). Pörtner, H.-O.; Roberts, D.C.; Tignor, M.; Poloczanska, E.S.; Mintenbeck, K.; Alegría, A.; Craig, M.; Langsdorf, S.; Löschke, S.; Möller, V.; Okem, A.; Rama, B.; et al. (eds.). Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press.

IPCC (2022). Shukla, P.R.; Skea, J.; Slade, R.; Al Khourdajie, A.; et al. (eds.). Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK and New York, NY, USA: Cambridge University Press. doi:10.1017/9781009157926. ISBN 978-1-009-15792-6.

IPCC (2023). Core Writing Team; Lee, H.; Romero, J.; et al. (eds.). IPCC, 2023: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (Eds.)]. IPCC, Geneva, Switzerland (PDF). Geneva, Switzerland: IPCC. doi:10.59327/IPCC/AR6-9789291691647. hdl:1885/299630. ISBN 978-92-9169-164-7. S2CID 260074696.

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In common usage, climate change describes global warming-the ongoing increase in global average temperature-and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is primarily caused by humans burning fossil fuels since the Industrial Revolution.

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Addressing Mental Health in Athletes | Mass General Brigham

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Mental health is essential to athletes’ health and performance. Learn how to identify signs of mental health struggles and what you can do to enhance athletes’ mental health.

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Climate change is important because it can cause a very big impact to our society and our lives. Goal 13 climate action

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Key facts

Climate change is directly contributing to humanitarian emergencies from heatwaves, wildfires, floods, tropical storms and hurricanes and they are increasing in scale, frequency and intensity.

Research shows that 3.6 billion people already live in areas highly susceptible to climate change. Between 2030 and 2050, climate change is expected to cause approximately 250 000 additional deaths per year, from undernutrition, malaria, diarrhoea and heat stress alone.

The direct damage costs to health (excluding costs in health-determining sectors such as agriculture and water and sanitation) is estimated to be between US$ 2-4 billion per year by 2030.

Areas with weak health infrastructure - mostly in developing countries - will be the least able to cope without assistance to prepare and respond.

Reducing emissions of greenhouse gases through better transport, food and energy use choices can result in very large gains for health, particularly through reduced air pollution.

Overview

Climate change presents a fundamental threat to human health. It affects the physical environment as well as all aspects of both natural and human systems - including social and economic conditions and the functioning of health systems. It is therefore a threat multiplier, undermining and potentially reversing decades of health progress. As climatic conditions change, more frequent and intensifying weather and climate events are observed, including storms, extreme heat, floods, droughts and wildfires. These weather and climate hazards affect health both directly and indirectly, increasing the risk of deaths, noncommunicable diseases, the emergence and spread of infectious diseases, and health emergencies.

Climate change is also having an impact on our health workforce and infrastructure, reducing capacity to provide universal health coverage (UHC). More fundamentally, climate shocks and growing stresses such as changing temperature and precipitation patterns, drought, floods and rising sea levels degrade the environmental and social determinants of physical and mental health. All aspects of health are affected by climate change, from clean air, water and soil to food systems and livelihoods. Further delay in tackling climate change will increase health risks, undermine decades of improvements in global health, and contravene our collective commitments to ensure the human right to health for all.

Climate change impacts on health

The Intergovernmental Panel on Climate Change's (IPCC) Sixth Assessment Report (AR6) concluded that climate risks are appearing faster and will become more severe sooner than previously expected, and it will be harder to adapt with increased global heating.

It further reveals that 3.6 billion people already live in areas highly susceptible to climate change. Despite contributing minimally to global emissions, low-income countries and small island developing states (SIDS) endure the harshest health impacts. In vulnerable regions, the death rate from extreme weather events in the last decade was 15 times higher than in less vulnerable ones.

Climate change is impacting health in a myriad of ways, including by leading to death and illness from increasingly frequent extreme weather events, such as heatwaves, storms and floods, the disruption of food systems, increases in zoonoses and food-, water- and vector-borne diseases, and mental health issues. Furthermore, climate change is undermining many of the social determinants for good health, such as livelihoods, equality and access to health care and social support structures. These climate-sensitive health risks are disproportionately felt by the most vulnerable and disadvantaged, including women, children, ethnic minorities, poor communities, migrants or displaced persons, older populations, and those with underlying health conditions.
Figure: An overview of climate-sensitive health risks, their exposure pathways and vulnerability factors. Climate change impacts health both directly and indirectly, and is strongly mediated by environmental, social and public health determinants.
Although it is unequivocal that climate change affects human health, it remains challenging to accurately estimate the scale and impact of many climate-sensitive health risks. However, scientific advances progressively allow us to attribute an increase in morbidity and mortality to global warming, and more accurately determine the risks and scale of these health threats.

WHO data indicates 2 billion people lack safe drinking water and 600 million suffer from foodborne illnesses annually, with children under 5 bearing 30% of foodborne fatalities. Climate stressors heighten waterborne and foodborne disease risks. In 2020, 770 million faced hunger, predominantly in Africa and Asia. Climate change affects food availability, quality and diversity, exacerbating food and nutrition crises.

Temperature and precipitation changes enhance the spread of vector-borne diseases. Without preventive actions, deaths from such diseases, currently over 700 000 annually, may rise. Climate change induces both immediate mental health issues, like anxiety and post-traumatic stress, and long-term disorders due to factors like displacement and disrupted social cohesion.

Recent research attributes 37% of heat-related deaths to human-induced climate change. Heat-related deaths among those over 65 have risen by 70% in two decades. In 2020, 98 million more experienced food insecurity compared to the 1981-2010 average. The WHO conservatively projects 250 000 additional yearly deaths by the 2030s due to climate change impacts on diseases like malaria and coastal flooding. However, modelling challenges persist, especially around capturing risks like drought and migration pressures.

The climate crisis threatens to undo the last 50 years of progress in development, global health and poverty reduction, and to further widen existing health inequalities between and within populations. It severely jeopardizes the realization of UHC in various ways, including by compounding the existing burden of disease and by exacerbating existing barriers to accessing health services, often at the times when they are most needed. Over 930 million people - around 12% of the world's population - spend at least 10% of their household budget to pay for health care. With the poorest people largely uninsured, health shocks and stresses already currently push around 100 million people into poverty every year, with the impacts of climate change worsening this trend.

Climate change and equity

In the short- to medium-term, the health impacts of climate change will be determined mainly by the vulnerability of populations, their resilience to the current rate of climate change and the extent and pace of adaptation. In the longer-term, the effects will increasingly depend on the extent to which transformational action is taken now to reduce emissions and avoid the breaching of dangerous temperature thresholds and potential irreversible tipping points.

While no one is safe from these risks, the people whose health is being harmed first and worst by the climate crisis are the people who contribute least to its causes, and who are least able to protect themselves and their families against it: people in low-income and disadvantaged countries and communities.

Addressing climate change's health burden underscores the equity imperative: those most responsible for emissions should bear the highest mitigation and adaptation costs, emphasizing health equity and vulnerable group prioritization.

Need for urgent action

To avert catastrophic health impacts and prevent millions of climate change-related deaths, the world must limit temperature rise to 1.5°C. Past emissions have already made a certain level of global temperature rise and other changes to the climate inevitable. Global heating of even 1.5°C is not considered safe, however; every additional tenth of a degree of warming will take a serious toll on people's lives and health.

WHO response

WHO's response to these challenges centres around 3 main objectives:

Promote actions that both reduce carbon emissions and improve health: supporting a rapid and equitable transition to a clean energy economy; ensuring that health is central to climate change mitigation policy; accelerating mitigation actions that bring the greatest health gains; and mobilizing the strength of the health community to drive policy change and build public support.

Build better, more climate-resilient and environmentally sustainable health systems: ensuring core services, environmental sustainability and climate resilience as central components of UHC and primary health care (PHC); supporting health systems to leapfrog to cheaper, more reliable and cleaner solutions, while decarbonizing high-emitting health systems; and mainstreaming climate resilience and environmental sustainability into health service investments, including the capacity of the health workforce.

Protect health from the wide range of impacts of climate change: assessing health vulnerabilities and developing health plans; integrating climate risk and implementing climate-informed surveillance and response systems for key risks, such as extreme heat and infectious disease; supporting resilience and adaptation in health-determining sectors such as water and food; and closing the financing gap for health adaptation and resilience.

Leadership and Raising Awareness: WHO leads in emphasizing climate change's health implications, aiming to centralize health in climate policies, including through the UNFCCC. Partnering with major health agencies, health professionals and civil society, WHO strives to embed climate change in health priorities like UHC and target carbon neutrality by 2030.

Evidence and Monitoring: WHO, with its network of global experts, contributes global evidence summaries, provides assistance to nations in their assessments, and monitors progress. The emphasis is on deploying effective policies and enhancing access to knowledge and data.

Capacity Building and Country Support: Through WHO offices, support is given to ministries of health, focusing on collaboration across sectors, updated guidance, hands-on training, and support for project preparation and execution as well as for securing climate and health funding. WHO leads the Alliance for Transformative Action on Climate and Health (ATACH), bringing together a range of health and development partners, to support countries in achieving their commitments to climate-resilient and low carbon health systems.

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WHO fact sheet on climate change and health: provides key facts, patterns of infection, measuring health effects and WHO response.

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Species List | Endangered, Vulnerable, and Threatened Animals | WWF

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WWF is committed to saving endangered species. Learn more about the species we are working to protecting from becoming endangered or extinct.

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Isla

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what has climate change affected in hong kong

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what has climate change affected in hong kong

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Goal 13 climate action

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Centre for Health Protection, Department of Health - Climate Change and Health

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Introduction Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activities. Human activities such as fossil fuel use, deforestation, and intensive livestock farming, have released sufficient amount of greenhouse gases to trap additional heat in the lower atmosphere and affect the global climate.
Affected by global warming and exacerbation of local urbanization, Hong Kong has also experienced temperature rises during the past several decades. More importantly, Hong Kong is expected to have an increase in the number of very hot days, average rainfall intensity, frequency of extreme rainfall events and rising sea level in this century. For more information about climate change in Hong Kong, please visit the relevant Hong Kong Observatory’s website.
Health effects of climate change
Climate change represents a fundamental threat to lives and wellbeing. Direct and indirect impacts of climate change threaten human health by affecting some of the fundamental determinants of health – weather, air, water and food as well as transmission pattern of different diseases. The climate change is one of the biggest global health issues of the 21st century.
The effects of climate change will vary in different geographical location. For example, the more hot days will increase the heat-related diseases but the warming will decrease the cold-related mortality in some regions. However, overall speaking, the negative effects are more than the positive effects.  Besides, some groups of people, such as the socially-deprived, children and elderly, are more vulnerable than others due to their particular sensitivities, high likelihood of exposure, low adaptive capacity, or combinations of these factors.
Some typical health effects by climate change are discussed below.
Extreme heat
Warmer average temperatures will lead to hotter days and more frequent and longer heat waves. Exposure to extreme heat and humidity without relief or adequate fluid intake can result in various types of heat-related illness, such as heat cramps, heat exhaustion, and even life-threatening heat stroke. Extreme high temperatures can also worsen chronic conditions such as cardiovascular and respiratory diseases.
Natural disasters and variable rainfall patterns
Global warming could increase the number and severity of extreme weather events such as storms, floods, droughts, and related landslides and wildfires. Such events could result in destruction of homes and other essential services, which cause injuries and deaths directly. Moreover, variable rainfall patterns could affect the adequate supply of fresh water and flooding could induce contamination to water supplies, in which both pose negative impact to the supply of safe drinking water.
Changes in transmission patterns of infectious diseases
Global warming also indirectly changes the transmission patterns of some infectious diseases, especially vector-borne diseases (VBDs). Changes in climate are likely to lengthen the transmission seasons of important VBDs and to expand their geographical range. Mosquitoes which transmit VBDs, such as malaria, dengue fever, and Japanese encephalitis, are particularly sensitive to meteorological conditions – warmer temperature and humid conditions increase their reproductive rate, biting activity and survival, and also shorten the incubation period of pathogens within them.
Air pollution
Burning fossil fuel produces not only carbon dioxide causing climate change, but also several pollutants resulting in air pollution. Besides, the changing climate has modified weather patterns, weather elements like temperature, humidity, wind, precipitation and extreme weather events can affect air pollutant emission, chemistry, deposition and transport. Poor air quality can negatively affect the human respiratory and cardiovascular systems.
Increasing carbon dioxide levels and temperatures could prolong pollen seasons and increase pollen concentrations which in turn contribute to allergic sensitization and trigger asthma in some people.
Further Information and Actions
You can follow the links below to find out more about climate change and its effects on human health.
World Health Organization: https://www.who.int/health-topics/climate-change
Acting on climate change is everyone’s responsibility. As responsible global citizens, we should cut down our own carbon footprint. Many mitigation measures have important direct health benefits as well as slowing down the pace of climate change. For example, active transportation such as walking and cycling, not only can reduce carbon emissions but also increase physical activity levels which can prevent some cancers, diabetes, heart diseases and obesity-related risks. Click here for more information about the health benefits of tackling climate change.

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https://www.healthdirect.gov.au/7-ways-pets-improve-your-health

https://psychcentral.com/health/having-a-pet-dog-linked-to-improved-social-emotional-development-in-young-children

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Pets might be a lot of work for families, but they can also be very good for your kid's mental and physical health.

When it comes to childhood milestones, there's one that we don't talk about as much: the moment our child asks us to get them a pet.

Maybe it happens after they watch the Sesame Street episode where Elmo finds a puppy or after they go to a friend's house and play with the new bearded dragon their family just got.

But chances are, it will happen. Do you know what you'll say?

As long as your family has the means and resources to take care of a pet and no one in the house is allergic, you might consider saying yes since pets can be very good for a child's well-being.

Whether it's a dog, cat, bunny, or reptile, pets can have very real and positive impacts on a kid's emotional and physical development. Here are some of those benefits:

Emotional regulation

"Humans have two systems of regulation: co-regulation and self-regulation," explains Kristen Antonio, licensed clinical counselor and school social worker from Massachusetts. "When children are born, they are biologically adapted to seek out the co-regulation from their caregivers."

This is why infants calm down when they're held. But over time, they learn ways to self-regulate or self-soothe. One of the major benefits of growing up with pets, Antonio says, is that they give the child practice in learning both these skills since pets can both provide comfort and be comforted by the child.

Pets and mental health

Pets offer humans of all ages connection, which several studies have shown can greatly improve our mental health.

A , for example, found that growing up with a childhood dog correlated with lower rates of anxiety in kids, while a 2013 study found that dogs reduced how often military veterans with PTSD felt lonely, worried, or irritable.

"Having a pet to interact with helps children with stress management," explains Mayra Mendez, licensed psychotherapist and program coordinator at the Providence Saint John's Child and Family Development Center in Santa Monica, California, "[because] play with a pet releases tension."

A 2015 review of studies showed that dogs and horses have been found to reduce feelings of depression and anxiety. They have also been shown to reduce PTSD symptoms. This is why they're often used as part of therapy interventions by mental health professionals.

"When I worked in a children's hospital, pet therapy visits were definitely a highlight for our patients," explains Jackie Tassiello, a licensed board certified art therapist who works with children. "Pets can offer us play, humor, connection, and an emotional anchor during stressful times."

"Children can learn to self-soothe, rest, and cope better with a pet," she adds.

Pets can teach social skills

Companion animals can be emotionally supportive and present with kids, but they also need things in return, such as love and care. That's why they can help the child better learn how to interact with other living things.

"Pets offer vital lessons around boundaries, connection, respect, and empathy," explains Tassiello. "Pets need care and connection, which activates the ability [in kids] to act in empathetic, compassionate ways and form strong bonds."

In other words, pets help teach kids how to trust and form healthy attachments.

"Play with a pet allows for the opportunity to engage in companionship and builds capacity for reciprocity and give and take," Tassiello adds.

Pets can influence behavior

Depending on what kind of pet you get, you might also help teach kids tolerance and acceptance.

"Pets have many needs and their own distinct personalities," explains Tassiello. "They get scared, make mistakes, and some may have particular strengths and weaknesses."

As a result, kids learn that they cannot control others.

"Children not only learn to be kind, but they may also take in lessons around tolerating differences, embracing imperfection, forgiveness, and taking on multiple perspectives."

Pets can improve communication skills

"Pets help children think and problem solve by interacting, playing, and [caregiving]," says Mendez. "Language and communication skills are enhanced and the process of teaching the pet tricks and positive behavior provides children with the opportunity to practice clear, accurate, and meaningful communication skills."

This is also why there are programs devoted to helping elementary school-aged children improve their reading skills.

Dogs are non-judgmental, comforting friends that will patiently listen, which gives children more self-esteem.

Pets teach life skills

Since pets are living, breathing animals that have needs, children can learn responsibility and dependability when they help care for them.

"For instance, if I am out with my kids and we need to get home to take our dog out, I am modeling for children how to think about and empathize with another living creature who is dependent on us for care," explains Antonio.

Plus, she continues, "Pets are also a beautiful source of empowerment for children who move through this world feeling quite disempowered in many spaces [because] to have a pet that they feel a sense of responsibility for is a beautiful way to help children build interpersonal skills that empower themselves and others."

For example, when training a dog, you can't just say "no" and expect the dog to adjust its behavior. You have to give the dog positive reinforcement for the behavior you do want to see. This teaches kids to manage expectations in a consistent, loving way.

Learning about loss and grief

Pets often become integrated family members, so when they die, they can teach the whole family lessons about how to deal with grief.

"Pets teach us that loss is complex, change is difficult, and that everyone's healing is unique and personal," says Tassiello. "Children benefit from having a say in how they want to process the loss and remember their pets and having a caring adult ask about their needs as they heal."

This helps kids learn coping skills and the importance of building and relying on their support system when they need it.

They encourage activity

Some pets, like dogs, require regular walks and outdoor time. This can encourage children to be more active and outdoorsy than they might otherwise be, which can benefit their health.

Pets can benefit kids' physical health in other ways too. For example, one found that babies with pets in their homes are less likely to develop allergies since they're exposed early in life to allergens like pet dander or dirt that pets bring inside.

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Why Should Kids Have Pets: 8 Evidence-Based Reasons

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Your child was right, owning a pet can be good for them: socially and emotionally. Here's what child experts and researchers say.

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How sports will affect your well being and health which is one of the 17 sustainable development goals. No. 3

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Sports Well | CUHK Medical Centre Limited

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A sporty lifestyle is welcome for its obvious health benefits. Beyond the more common sports - football, basketball, gym and yoga, many are engaged in higher intensity options such as long-distance running (e.g. Marathon), cross country running, long-distance cycling and triathlon, challenging one’s limit with participation in events local or abroad.

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Yixuan Shen : Music - N.4 quality education

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Yixuan Shen : Music - N.4 quality education

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Music helps our brain make connections that support our learning in other areas, such as literacy and numeracy. Music helps us express and engage with our emotions. Music helps us make sense of the world around us, and is an ancient and universal language common to every single human culture.

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Why Is Music Education Important? | Northern Territory Music School

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Every child deserves a quality music education. Not just because we want to nurture the next Jessica Mauboy or Gurrumul Yunupingu, but because music is good.

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pet shelter - life on land

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Ecosystems exist because of animals and biodiversity (the processes that deliver all our human life support needs) come from ecosystems. Conservation Why is animal conservation important? Animal conservation is important, because animals are the only mechanism to create biodiversity, which is the mechanism that creates a habitable planet for humans. Without animals, the energy from today's plants (algae, trees, flowers etc) will eventually reach the atmosphere and ocean, much of it as carbon. The quantity of this plant-based waste is so of wildlife is critical to human survival. According to the United Nations Sustainable Development Goal (SDGs) 15 ( Life on Land), we deforest 13 million hectares every year and have stripped soil fertility from 3.6 billion hectares. The ongoing destruction of wildlife habitat, trade in endangered species and persecution of animals, affects our access to the most basic life support needs of food and water. Here are 5 reasons to conserve land animals and ecosystems. Wildlife conservation is important and we must protect endangered species.

1. Over half the world's human population depends on nature

Over half of the world's human population directly depends on healthy landscapes and ecosystems for survival. About 1.6 billion depend on forests and 2.6 billion depend directly on agriculture for a living.

2. Conservation is essential for climate stability

The stability of climate and maximum capture of carbon depends on wildlife-rich habitats. The natural world can contribute about a third of CO₂ reductions by 2030.

3. Wildlife provides global food security

About eighty percent of all the known species of land animals, plants and insects have been found in forests. At a scale of 25×25 cm, the most species-rich habitats on Earth are grasslands, such as those in central Europe. They are 7,500 times more species-rich than a hectare of the Ecuadorian rainforest. Our wildlife is essential to maintaining the biodiversity processes that build ecosystems and deliver soil fertility and food security.

4. Ecosystems are worth far more than global GDP

For human livelihoods and well-being, the value of land-based ecosystems has been estimated at $US125 trillion per year. That's five times more than the global cost of the COVID pandemic, according to the International Monetary Fund and about $30 trillion more than the world's GDP (estimates that don't include nature-based value). This means the real GDP is double what we think it is: over $200 trillion and we're massively underestimating the significance of nature.

5. Nature delivers critical fresh water

Mountains provide 60-80 percent of the Earth's fresh water. Sustainable flow of clear and clean fresh water is dependent on healthy vegetation and this cannot exist without wildlife. Animals are the mechanism behind the diversity of vegetation and this is what binds soil processes together, stabilising landscapes and climate. Water scarcity will become one of our greatest challenges and can only be addressed, by rebuilding nature-based systems.

Why is ocean conservation important? The temperature, chemistry and nutrientA substance that contains the raw materials for life. At a chemical level, these are contained inside compounds that are absorbed...

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5 reasons to conserve land animals and ecosystems - Wildlife in the Balance

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5 reasons to conserve land animals and ecosystems. Conservation of wildlife is critical to human survival, life support and ecosystems.

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By Alexandra Frost
Since her grandfather died five years ago, Casey Clark doesn't go a day without listening to music. It helps her cope with the grief, depression, and symptoms of post traumatic stress disorder (PTSD) from seeing him in the hospital before he passed. When her symptoms flare, she listens to a Michael Bublé album because it was the last present she gave her grandfather, and they shared many happy memories listening to it together.

"It sounds cliché, but music actually serves as an escape in those moments when the flashbacks are so intense, and I can't get out of them with other grounding techniques," says Clark, 22, a writer who lives in New York City. It's the only way she's found to put those thoughts on pause.

The teen and young adult years have long been known as the most pivotal in developing a personal taste in music, and for many, it's the time that music matters the most. The average teen spends 2.5 hours per day listening to music, and over half of young adults , ages 18 to 29, report streaming music every day (compared to 24% of all adults).

This is good news, because music can be a great way to take care of your mental health.

Music can be distracting and lower your stress

"Music serves as a temporary distraction from the symptoms of my mental health issues," says Clark. In fact, research has shown that it can lessen the impact of depression and anxiety. A study done in 2019 found that college students who listened to classical music every day for two months lowered their levels of anxiety significantly.

Another 2016 study looked at the connection between music and anxiety by studying people who have a fear of heights. All of the participants were put in a virtual reality simulation of riding up nine floors in an elevator. One group listened to music during the experiment, and the other didn't. The researchers found that the people who listened to music recovered faster from the stress of the experience than those who didn't. And many studies have shown that listening to music can lower your blood pressure and your heart rate (both spike when you're stressed), and even lower stress hormones in your body.

When you want music to give you a break from what you're going through, pick songs that have a storyline different from the challenges you're facing, recommends Bethany Cook, PsyD, a psychologist and music therapist in Chicago. This can temporarily transport you elsewhere and give you a short break from your concerns, just like when you read a good book.

Music can help you feel your feelings

When her clients are in a bad mood or managing difficult emotions about the current state of the world, Cook recommends putting on a piece of classical music. "Listening to music that does not have lyrics attached to it lets the listener project their personal feelings and their personal struggle into the music," she says. And some research has found that even listening to "sad" music can make you feel some pleasant emotions, which might lessen the pain you are feeling or allow you to more safely feel sad feelings we sometimes try to avoid in life.

Music can make it easier to talk about what's troubling you

If you don't have the words to explain what you are going through, or if you don't feel comfortable talking about it, song lyrics can give you another way to express your feelings. Lyrics give you permission to better understand your own situation through someone else's perspective, says Cook . She uses something called "lyric analysis" when she works with kids and teens in group therapy settings. You can try it alone or with a friend or loved one. Here's how:

Bring up the lyrics on your phone(s).

Listen to the song.

Mark or highlight words and sentences that stand out to you.

Listen to the song again, pausing at the marked places, and discuss or think about why those lyrics spoke to you and how you relate to them.

Listen a final time reflecting on your new appreciation of what the song means to you or your friends.

Music can help you figure out who you are

Discovering music that resonates is one key way teens and young adults define who they are and who they want to be , says Michael Viega , PhD, a professor of music therapy at Montclair State University in Montclair, New Jersey. Both Viega and Cook strongly encourage parents, teachers, and caregivers to approach teens' and young adults' music with curiosity.

Showing interest in musical taste is a way to show an interest in who a young person is or is becoming. Even listening to music with questionable lyrics is an "opportunity," says Viega. It gives caregivers a chance to open a dialogue, asking teens what they think is happening in the song. Doing so can lead to meaningful conversations about important topics that can be difficult to talk about, says Viega.

"Music first turned me on to drag culture and the queer community when I was a teenager," says Viega. "It turned me on to feminist ideals, to ecology and ecological thinking."

Music builds community

Making music-through singing or playing an instrument in school, in a band, or with friends-can connect you with a community of people who share a common interest. And even if you don't play or sing, you can also find people who share your love for a particular band or type of music. Feeling a sense of belonging to something larger than yourself is a proven way to improve mental health.

Music builds your brain's capacity and connections

Music can improve the connection between your left and right brain, says Cook, who created a TikTok video describing the connections. She encourages people of all ages to try playing music-not to become a high-performing musician, but for their own brain development and health.

Music can be a quick mood booster

This is probably one of those things you don't need research to prove, but scientific research has found that listening to upbeat music with an intention of getting in a better mood actually works. Of course, this is something you can also research yourself on the daily.

Music can also benefit people who are deaf or have hearing loss

Research into music therapy for people who are deaf and also have mental health disorders is more limited, but case studies suggest, just as in hearing people, music can help people with hearing loss express emotions and improve cognitive abilities. Cook uses table drums to connect with her deaf cousin. "Table drums are massive, and you can lie underneath them and all of that sound vibration goes straight into your body," says Cook. Playing them together with her cousin has increased their connection and nonverbal communication.

If you would like to explore using music to make you feel better emotionally, Cook and Viega recommend:

Sampling different types of music to expand your horizons and find what you like.

Using music as a stress reliever when you are feeling anxious.

Discussing meaningful song lyrics with a friend.

Trying an instrument.

Talking about why you love a particular song with the adults in your life (or, if you're a caregiver, with your teen).

Listening to classical music when you have confusing or difficult emotions.

Creating playlists to match or inspire different moods.

Search Resource Center

Type your search term below

# data[].attributes.attachment_link.title
How Music Can Improve Your Mental Health

# data[].attributes.attachment_link.description
By Alexandra Frost Since her grandfather died five years ago, Casey Clark doesn't go a day without listening to music. It helps her cope with the grief, depression, and symptoms of post traumatic stress disorder (PTSD) from seeing him in the hospital before he passed.

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effenc of climate change

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The effects of human-caused global warming are happening now, are irreversible for people alive today, and will worsen as long as humans add greenhouse gases to the atmosphere.

We already see effects scientists predicted, such as the loss of sea ice, melting glaciers and ice sheets, sea level rise, and more intense heat waves.

Scientists predict global temperature increases from human-made greenhouse gases will continue. Severe weather damage will also increase and intensify.

Earth Will Continue to Warm and the Effects Will Be Profound

Global climate change is not a future problem. Changes to Earth's climate driven by increased human emissions of heat-trapping greenhouse gases are already having widespread effects on the environment: glaciers and ice sheets are shrinking, river and lake ice is breaking up earlier, plant and animal geographic ranges are shifting, and plants and trees are blooming sooner.

Effects that scientists had long predicted would result from global climate change are now occurring, such as sea ice loss, accelerated sea level rise, and longer, more intense heat waves.

The magnitude and rate of climate change and associated risks depend strongly on near-term mitigation and adaptation actions, and projected adverse impacts and related losses and damages escalate with every increment of global warming.

Intergovernmental Panel on Climate Change

Some changes (such as droughts, wildfires, and extreme rainfall) are happening faster than scientists previously assessed. In fact, according to the Intergovernmental Panel on Climate Change (IPCC) - the United Nations body established to assess the science related to climate change - modern humans have never before seen the observed changes in our global climate, and some of these changes are irreversible over the next hundreds to thousands of years.

Scientists have high confidence that global temperatures will continue to rise for many decades, mainly due to greenhouse gases produced by human activities.

The IPCC's Sixth Assessment report, published in 2021, found that human emissions of heat-trapping gases have already warmed the climate by nearly 2 degrees Fahrenheit (1.1 degrees Celsius) since 1850-1900.1 The global average temperature is expected to reach or exceed 1.5 degrees C (about 3 degrees F) within the next few decades. These changes will affect all regions of Earth.

The severity of effects caused by climate change will depend on the path of future human activities. More greenhouse gas emissions will lead to more climate extremes and widespread damaging effects across our planet. However, those future effects depend on the total amount of carbon dioxide we emit. So, if we can reduce emissions, we may avoid some of the worst effects.

The scientific evidence is unequivocal: climate change is a threat to human wellbeing and the health of the planet. Any further delay in concerted global action will miss the brief, rapidly closing window to secure a liveable future.

Intergovernmental Panel on Climate Change

Here are some of the expected effects of global climate change on the United States, according to the Third and Fourth National Climate Assessment Reports:

Future effects of global climate change in the United States:

Longer Wildfire Season

Warming temperatures have extended and intensified wildfire season in the West, where long-term drought in the region has heightened the risk of fires. Scientists estimate that human-caused climate change has already doubled the area of forest burned in recent decades. By around 2050, the amount of land consumed by wildfires in Western states is projected to further increase by two to six times. Even in traditionally rainy regions like the Southeast, wildfires are projected to increase by about 30%.

Frost-Free Season (and Growing Season) will Lengthen

The length of the frost-free season, and the corresponding growing season, has been increasing since the 1980s, with the largest increases occurring in the western United States. Across the United States, the growing season is projected to continue to lengthen, which will affect ecosystems and agriculture.

Arctic Is Very Likely to Become Ice-Free

Sea ice cover in the Arctic Ocean is expected to continue decreasing, and the Arctic Ocean will very likely become essentially ice-free in late summer if current projections hold. This change is expected to occur before mid-century.

Climate change is bringing different types of challenges to each region of the country. Some of the current and future impacts are summarized below. These findings are from the Third3 and Fourth4 National Climate Assessment Reports, released by the U.S. Global Change Research Program.

Northeast. Heat waves, heavy downpours, and sea level rise pose increasing challenges to many aspects of life in the Northeast. Infrastructure, agriculture, fisheries, and ecosystems will be increasingly compromised. Farmers can explore new crop options, but these adaptations are not cost- or risk-free. Moreover, adaptive capacity, which varies throughout the region, could be overwhelmed by a changing climate. Many states and cities are beginning to incorporate climate change into their planning.

Northwest. Changes in the timing of peak flows in rivers and streams are reducing water supplies and worsening competing demands for water. Sea level rise, erosion, flooding, risks to infrastructure, and increasing ocean acidity pose major threats. Increasing wildfire incidence and severity, heat waves, insect outbreaks, and tree diseases are causing widespread forest die-off.

Southeast. Sea level rise poses widespread and continuing threats to the region's economy and environment. Extreme heat will affect health, energy, agriculture, and more. Decreased water availability will have economic and environmental impacts.

Midwest. Extreme heat, heavy downpours, and flooding will affect infrastructure, health, agriculture, forestry, transportation, air and water quality, and more. Climate change will also worsen a range of risks to the Great Lakes.

Southwest. Climate change has caused increased heat, drought, and insect outbreaks. In turn, these changes have made wildfires more numerous and severe. The warming climate has also caused a decline in water supplies, reduced agricultural yields, and triggered heat-related health impacts in cities. In coastal areas, flooding and erosion are additional concerns.

Discover More Topics From NASA

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Takeaways Earth Will Continue to Warm and the Effects Will Be Profound Global climate change is not a future problem. Changes to Earth's climate driven by increased human emissions of heat-trapping greenhouse gases are already having widespread effects on the environment: glaciers and ice sheets are shrinking, river and lake ice is breaking up earlier, [...]

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By Alexandra Frost
Since her grandfather died five years ago, Casey Clark doesn't go a day without listening to music. It helps her cope with the grief, depression, and symptoms of post traumatic stress disorder (PTSD) from seeing him in the hospital before he passed. When her symptoms flare, she listens to a Michael Bublé album because it was the last present she gave her grandfather, and they shared many happy memories listening to it together.

"It sounds cliché, but music actually serves as an escape in those moments when the flashbacks are so intense, and I can't get out of them with other grounding techniques," says Clark, 22, a writer who lives in New York City. It's the only way she's found to put those thoughts on pause.

The teen and young adult years have long been known as the most pivotal in developing a personal taste in music, and for many, it's the time that music matters the most. The average teen spends 2.5 hours per day listening to music, and over half of young adults , ages 18 to 29, report streaming music every day (compared to 24% of all adults).

This is good news, because music can be a great way to take care of your mental health.

Music can be distracting and lower your stress

"Music serves as a temporary distraction from the symptoms of my mental health issues," says Clark. In fact, research has shown that it can lessen the impact of depression and anxiety. A study done in 2019 found that college students who listened to classical music every day for two months lowered their levels of anxiety significantly.

Another 2016 study looked at the connection between music and anxiety by studying people who have a fear of heights. All of the participants were put in a virtual reality simulation of riding up nine floors in an elevator. One group listened to music during the experiment, and the other didn't. The researchers found that the people who listened to music recovered faster from the stress of the experience than those who didn't. And many studies have shown that listening to music can lower your blood pressure and your heart rate (both spike when you're stressed), and even lower stress hormones in your body.

When you want music to give you a break from what you're going through, pick songs that have a storyline different from the challenges you're facing, recommends Bethany Cook, PsyD, a psychologist and music therapist in Chicago. This can temporarily transport you elsewhere and give you a short break from your concerns, just like when you read a good book.

Music can help you feel your feelings

When her clients are in a bad mood or managing difficult emotions about the current state of the world, Cook recommends putting on a piece of classical music. "Listening to music that does not have lyrics attached to it lets the listener project their personal feelings and their personal struggle into the music," she says. And some research has found that even listening to "sad" music can make you feel some pleasant emotions, which might lessen the pain you are feeling or allow you to more safely feel sad feelings we sometimes try to avoid in life.

Music can make it easier to talk about what's troubling you

If you don't have the words to explain what you are going through, or if you don't feel comfortable talking about it, song lyrics can give you another way to express your feelings. Lyrics give you permission to better understand your own situation through someone else's perspective, says Cook . She uses something called "lyric analysis" when she works with kids and teens in group therapy settings. You can try it alone or with a friend or loved one. Here's how:

Bring up the lyrics on your phone(s).

Listen to the song.

Mark or highlight words and sentences that stand out to you.

Listen to the song again, pausing at the marked places, and discuss or think about why those lyrics spoke to you and how you relate to them.

Listen a final time reflecting on your new appreciation of what the song means to you or your friends.

Music can help you figure out who you are

Discovering music that resonates is one key way teens and young adults define who they are and who they want to be , says Michael Viega , PhD, a professor of music therapy at Montclair State University in Montclair, New Jersey. Both Viega and Cook strongly encourage parents, teachers, and caregivers to approach teens' and young adults' music with curiosity.

Showing interest in musical taste is a way to show an interest in who a young person is or is becoming. Even listening to music with questionable lyrics is an "opportunity," says Viega. It gives caregivers a chance to open a dialogue, asking teens what they think is happening in the song. Doing so can lead to meaningful conversations about important topics that can be difficult to talk about, says Viega.

"Music first turned me on to drag culture and the queer community when I was a teenager," says Viega. "It turned me on to feminist ideals, to ecology and ecological thinking."

Music builds community

Making music-through singing or playing an instrument in school, in a band, or with friends-can connect you with a community of people who share a common interest. And even if you don't play or sing, you can also find people who share your love for a particular band or type of music. Feeling a sense of belonging to something larger than yourself is a proven way to improve mental health.

Music builds your brain's capacity and connections

Music can improve the connection between your left and right brain, says Cook, who created a TikTok video describing the connections. She encourages people of all ages to try playing music-not to become a high-performing musician, but for their own brain development and health.

Music can be a quick mood booster

This is probably one of those things you don't need research to prove, but scientific research has found that listening to upbeat music with an intention of getting in a better mood actually works. Of course, this is something you can also research yourself on the daily.

Music can also benefit people who are deaf or have hearing loss

Research into music therapy for people who are deaf and also have mental health disorders is more limited, but case studies suggest, just as in hearing people, music can help people with hearing loss express emotions and improve cognitive abilities. Cook uses table drums to connect with her deaf cousin. "Table drums are massive, and you can lie underneath them and all of that sound vibration goes straight into your body," says Cook. Playing them together with her cousin has increased their connection and nonverbal communication.

If you would like to explore using music to make you feel better emotionally, Cook and Viega recommend:

Sampling different types of music to expand your horizons and find what you like.

Using music as a stress reliever when you are feeling anxious.

Discussing meaningful song lyrics with a friend.

Trying an instrument.

Talking about why you love a particular song with the adults in your life (or, if you're a caregiver, with your teen).

Listening to classical music when you have confusing or difficult emotions.

Creating playlists to match or inspire different moods.

Search Resource Center

Type your search term below

# data[].attributes.attachment_link.title
How Music Can Improve Your Mental Health

# data[].attributes.attachment_link.description
By Alexandra Frost Since her grandfather died five years ago, Casey Clark doesn't go a day without listening to music. It helps her cope with the grief, depression, and symptoms of post traumatic stress disorder (PTSD) from seeing him in the hospital before he passed.

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Lewis

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Nearly 80% of respondents believe Hong Kong's pet trade regulations should be tightened

6 Sep, 2023, Hong Kong - As Hong Kong has grown to dominate international trade in a range of exotic animals, a survey of local residents reveals concerns about the prevalence of threatened species.

Globally, wildlife populations have declined by 69% since 1970, according to WWF's Living Planet Report. The wholesale extraction of animals from natural ecosystems to meet the demands of the exotic pet industry is a significant contributor to these declines. According to ADM Capital Foundation (ADMCF), between 2015 and 2021, the city imported at least 5.2 million exotic animals, drawn from over 760 species of reptiles, birds, mammals, amphibians and arthropods. Over this period Hong Kong led the global trade in endangered reptiles.

"Of the millions of exotic animals imported into the city, nearly half are from species facing extinction in the wild," saidProf Sung Yik Hei, Adjunct Assistant Professor, Science Unit of Lingnan University. He added that "Hong Kong is the last remaining stronghold for several species in trade, which could disappear within a matter of years. Despite our impact on wildlife, both at home and abroad, we are not acting fast enough or providing sufficient safeguards for endangered animals we are plundering from the wild."

"As the leading importer of many species of live exotics, arriving from over 90 countries, Hong Kong has a responsibility to the global community to ensure that the trade is not only sustainable, but also safe and includes only suitable species," saidSophie le Clue, CEO of ADMCF.

Commissioned by WWF-Hong Kong and ADMCF, the survey found that respondents had strong concerns about the impacts of the trade. At least 56% thought that keeping exotics pets has contributed to the risk of extinction of wild species and just 12% felt that keeping threatened species as a pet was acceptable.

Respondents also expressed a desire for more information from the Government. Only 5% felt familiar with the regulations. More than 85% expressed support for efforts to develop and standardise information on husbandry/care and animal welfare, as well as providing lists of qualified veterinarians and pet shops, which could be shared with exotic pet owners.

These concerns are well-founded and important in the context of the exotic pet trade. A patchwork of at least seven ordinances governs the trade. These can be challenging to understand and have loopholes. Government guidance for pet owners and traders is sparse, in many instances providing for the bare minimum, despite the complex husbandry need of exotic animals.

Around half of respondents viewed the current regulations related to the pet trade as lenient and a majority expressed support for tightening them. 80% of respondents supported restrictions on the trade of certain species of exotic pets and 89% agreed that documentation confirming legality of threatened species should be required ahead of a purchase.

"The absence of stringent biosecurity measures exposes animals, humans, and the environment to the spread and impact of infectious diseases," saidDr Bosco Chan, Conservation Director of WWF-Hong Kong. He continued, noting "It is essential that existing and prospective exotic pet owners have sufficient information to make informed decisions" and encouraged everyone to "think twice before acquiring an exotic pet."

WWF-Hong Kong and ADMCF urge the government to take steps to enhance regulation of the trade and promote public awareness of its complexities. To develop a responsible, sustainable trade in exotic animals that protects animals and their ecosystems. Recommended actions include:

1. Establishing a list of exotic pets that are either explicitly permitted or prohibited to be imported, sold or owned in Hong Kong.

2. Enhancing traceability to better understand supply chains and what is happening to exotics in the city.

3. Introducing schemes to positively incentivise the trade to improve practices.

A promotional video has been created jointly to draw attention to concerns about the exotic pet trade and to serve as a reminder that exotics areborn for the wild, not for our homes. It sheds light on various exotic animals, such as the African grey parrot, sugar glider, green iguana, scorpion, and African spurred tortoise, which are emblematic of various issues in Hong Kong. The video is being screened in MTR stations, a theme park and shopping malls, including the following:

Mong Kok, Prince Edward and Yau Ma Tei MTR: 18-31st August
Langham Mall: 4-17th September
Festival Walk: 17-30th August
Plaza Hollywood: 21st August - 3rd September
Noah's Ark Hong Kong: 24th August onwards

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Hongkongers Support Stricter Controls, as City Dominates Global Trade in Threatened Species

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Nearly 80% of respondents believe Hong Kong's pet trade regulations should be tightened 6 Sep, 2023, Hong Kong - As Hong Kong has grown to dominate international trade in a range of exotic animals, a survey of local residents reveals concerns about the prevalence of threatened species. &nbsp

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Pet parrot - life on land

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Please note: Our birds are not available for online purchase. To learn more about our feathered friends and find the perfect companion for you, please contact us at 954-725-0088. Free shipping is offered for Bird Products only. Live Bird Shipments require VIP (Very Important Parrot, that is) Services. Call us for more

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A circular economy eliminates waste, circulates products and materials, and regenerates nature.

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Although it may not look like my topic... it is actually one of the main ideas I have for my topic.

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By ,

Hong Kong is taking a major step in its war on waste by banning many single-use plastics. New rules, which come into force on the symbolic date of April 22, 2024 - on Earth Day - aim to cut down on non-biodegradable plastics in landfill sites. The first phase prohibits the sale and distribution of single-use plastics such as straws and cutlery, as well as styrofoam food containers. Phase two, which could start as early as 2025, will ban single-use plastic cups and boxes for takeaway services.
Here's a visual guide to the new rules.

Lunch experiment: how much plastic waste?

Hong Kong, a bustling city of nearly 7.5 million, has more than 17,000 restaurants. People throw out tens of thousands of tonnes of plastic every year, much of it packaging waste from takeaway meals. In a small experiment conducted March 18-22 before the ban, six members of South China Morning Post's graphics team kept track of the disposable packaging and utensils that came with their takeaway lunches.

New regulations

Recycling in Hong Kong

Every day in Hong Kong, thousands of tonnes of garbage including plastic waste needs to be disposed of at three strategic landfills. The facilities have a total capacity of 139 million ㎥. This would be the equivalent of a giant cube more than 518 metres high.

Treatment and recycling facility

In 2022, Hong Kong generated 5.97 million tonnes of municipal solid waste (MSW) with more than 4 million tonnes (almost 70%) ending up in two landfills, while the rest was recovered for recycling either locally or by exporting. Plastic waste was the second largest contributor with 2,369 tonnes per day. Only 12.3% of Hong Kong's total plastic waste is recovered for recycling.

Amount of plastic waste recycled in Hong Kong in 2022

Food and other municipal solid waste

Most facilities in Hong Kong are small and rely mainly on manual sorting. Hong Kong does not have any of the typical material recovery facilities (MRF) found in developed countries. Plastics mixed with generic waste, contaminated with stains, or wrapped in plastic bags will likely end up in landfill. This highlights why people should sort their own rubbish for recycling.

Hong Kong recycling capabilities compared with other places

Percentage collected for recycling

Hong Kong's waste-charging scheme

Hong Kong's new waste charging scheme will take effect on August 1, 2024. From this date, residents will be required to use prepaid, government-approved garbage bags to dispose of trash. Under the charge-per-bag arrangement, residents will pay 11 Hong Kong cents (1 US cent) for each litre of garbage they throw away. Bags will come in nine sizes.

To reduce MSW costs, people are encouraged to make use of free recycling initiatives such as GREEN@COMMUNITY.

What is GREEN@COMMUNITY?

It is a community recycling network developed by Hong Kong's Environmental Protection Department. People can sort their garbage into 11 categories and dispose of it at facilities throughout Hong Kong.

Global plastic pollution

Plastic consumption varies among countries and territories. According to Environmental Action's 2024 Plastic Overshoot report, people in Belgium are the top generators of plastic waste, with 147.7kg per person a year. Hong Kong is among the world's highest per capita plastic consumers.

Plastic consumption per person in a year

(kg)

In March 2022, the United Nations approved a landmark agreement to create the world's first ever global plastic pollution treaty. Even before that, nations and territories began regulating or banning single-use plastics. Here's a look.

Associate Creative Director Marcelo Duhalde
Edited by Andrew London

Sources: South China Morning Post archives, Hong Kong Environmental Protection Department, Hong Kong Census and Statistics Department, Plastic Overshoot Report

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Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic-Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous-Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs-birds-and the extinct non-avian dinosaurs, which are all dinosaurs other than birds.

Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among the most diverse groups of vertebrates. Using fossil evidence, paleontologists have identified over 900 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through the first half of the 20th century, before birds were recognized as dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some were herbivorous, others carnivorous. Evidence suggests that all dinosaurs were egg-laying, and that nest-building was a trait shared by many dinosaurs, both avian and non-avian.

While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage (birds) are generally small due to the constraints of flight, many prehistoric dinosaurs (non-avian and avian) were large-bodied-the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters (130 feet) and heights of 18 m (59 ft) and were the largest land animals of all time. The misconception that non-avian dinosaurs were uniformly gigantic is based in part on preservation bias, as large, sturdy bones are more likely to last until they are fossilized. Many dinosaurs were quite small, some measuring about 50 centimeters (20 inches) in length.

The first dinosaur fossils were recognized in the early 19th century, with the name "dinosaur" (meaning "terrible lizard") being coined by Sir Richard Owen in 1842 to refer to these "great fossil lizards". Since then, mounted fossil dinosaur skeletons have been major attractions at museums worldwide, and dinosaurs have become an enduring part of popular culture. The large sizes of some dinosaurs, as well as their seemingly monstrous and fantastic nature, have ensured their regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, and new discoveries are regularly covered by the media.

Definition

Under phylogenetic nomenclature, dinosaurs are usually defined as the group consisting of the most recent common ancestor (MRCA) of Triceratops and modern birds (Neornithes), and all its descendants. It has also been suggested that Dinosauria be defined with respect to the MRCA of Megalosaurus and , because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria. Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia". This definition includes major groups such as ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (bipedal or quadrupedal herbivores with neck frills), pachycephalosaurians (bipedal herbivores with thick skulls), ornithopods (bipedal or quadrupedal herbivores including " duck-bills"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).

Birds are the sole surviving dinosaurs. In traditional taxonomy, birds were considered a separate class that had evolved from dinosaurs, a distinct superorder. However, a majority of contemporary paleontologists concerned with dinosaurs reject the traditional style of classification in favor of phylogenetic taxonomy; this approach requires that, for a group to be natural, all descendants of members of the group must be included in the group. Birds belong to the dinosaur subgroup Maniraptora, which are coelurosaurs, which are theropods, which are saurischians.

Research by Matthew G. Baron, David B. Norman, and Paul M. Barrett in 2017 suggested a radical revision of dinosaurian systematics. Phylogenetic analysis by Baron et al. recovered the Ornithischia as being closer to the Theropoda than the Sauropodomorpha, as opposed to the traditional union of theropods with sauropodomorphs. This would cause sauropods and kin to fall outside traditional dinosaurs, so they re-defined Dinosauria as the last common ancestor of Triceratops horridus, Passer domesticus and Diplodocus carnegii, and all of its descendants, to ensure that sauropods and kin remain included as dinosaurs. They also resurrected the clade Ornithoscelida to refer to the group containing Ornithischia and Theropoda.

General description

Using one of the above definitions, dinosaurs can be generally described as archosaurs with hind limbs held erect beneath the body. Other prehistoric animals, including pterosaurs, mosasaurs, ichthyosaurs, plesiosaurs, and Dimetrodon, while often popularly conceived of as dinosaurs, are not taxonomically classified as dinosaurs. Pterosaurs are distantly related to dinosaurs, being members of the clade Ornithodira. The other groups mentioned are, like dinosaurs and pterosaurs, members of Sauropsida (the reptile and bird clade), except Dimetrodon (which is a synapsid). None of them had the erect hind limb posture characteristic of true dinosaurs.

Dinosaurs were the dominant terrestrial vertebrates of the Mesozoic Era, especially the Jurassic and Cretaceous periods. Other groups of animals were restricted in size and niches; mammals, for example, rarely exceeded the size of a domestic cat, and were generally rodent-sized carnivores of small prey. They have always been recognized as an extremely varied group of animals; over 900 non-avian dinosaur genera have been identified with certainty as of 2018, and the total number of genera preserved in the fossil record has been estimated at around 1850, nearly 75% of which remain to be discovered, and 1124 species by 2016. A 1995 study predicted that about 3,400 dinosaur genera ever existed, including many that would not have been preserved in the fossil record.

In 2016, the estimated number of dinosaur species that existed in the Mesozoic was 1,543-2,468. In 2021, the number of modern-day birds (avian dinosaurs) was estimated to be at 10,806 species. Some are herbivorous, others carnivorous, including seed-eaters, fish-eaters, insectivores, and omnivores. While dinosaurs were ancestrally bipedal (as are all modern birds), some prehistoric species were quadrupeds, and others, such as Anchisaurus and Iguanodon, could walk just as easily on two or four legs. Cranial modifications like horns and crests are common dinosaurian traits, and some extinct species had bony armor. Although known for large size, many Mesozoic dinosaurs were human-sized or smaller, and modern birds are generally small in size. Dinosaurs today inhabit every continent, and fossils show that they had achieved global distribution by at least the Early Jurassic epoch. Modern birds inhabit most available habitats, from terrestrial to marine, and there is evidence that some non-avian dinosaurs (such as Microraptor) could fly or at least glide, and others, such as spinosaurids, had semiaquatic habits.

Distinguishing anatomical features

In the skull, a supratemporal fossa (excavation) is present in front of the supratemporal fenestra, the main opening in the rear skull roof

Epipophyses, obliquely backward-pointing processes on the rear top corners of the anterior (front) neck vertebrae behind the atlas and axis, the first two neck vertebrae

Apex of a deltopectoral crest (a projection on which the deltopectoral muscles attach) located at or more than 30% down the length of the humerus (upper arm bone)

Radius, a lower arm bone, shorter than 80% of humerus length

Fourth trochanter (projection where the caudofemoralis muscle attaches on the inner rear shaft) on the femur (thigh bone) is a sharp flange

Fourth trochanter asymmetrical, with distal, lower, margin forming a steeper angle to the shaft

On the astragalus and calcaneum, upper ankle bones, the proximal articular facet, the top connecting surface, for the fibula occupies less than 30% of the transverse width of the element

Exoccipitals (bones at the back of the skull) do not meet along the midline on the floor of the endocranial cavity, the inner space of the braincase

In the pelvis, the proximal articular surfaces of the ischium with the ilium and the pubis are separated by a large concave surface (on the upper side of the ischium a part of the open hip joint is located between the contacts with the pubic bone and the ilium)

Cnemial crest on the tibia (protruding part of the top surface of the shinbone) arcs anterolaterally (curves to the front and the outer side)

Distinct proximodistally oriented (vertical) ridge present on the posterior face of the distal end of the tibia (the rear surface of the lower end of the shinbone)

Concave articular surface for the fibula of the calcaneum (the top surface of the calcaneum, where it touches the fibula, has a hollow profile)

A variety of other skeletal features are shared by dinosaurs. However, because they either are common to other groups of archosaurs or were not present in all early dinosaurs, these features are not considered to be synapomorphies. For example, as diapsids, dinosaurs ancestrally had two pairs of Infratemporal fenestrae (openings in the skull behind the eyes), and as members of the diapsid group Archosauria, had additional openings in the snout and lower jaw. Additionally, several characteristics once thought to be synapomorphies are now known to have appeared before dinosaurs, or were absent in the earliest dinosaurs and independently evolved by different dinosaur groups. These include an elongated scapula, or shoulder blade; a sacrum composed of three or more fused vertebrae (three are found in some other archosaurs, but only two are found in Herrerasaurus); and a perforate acetabulum, or hip socket, with a hole at the center of its inside surface (closed in Saturnalia tupiniquim, for example). Another difficulty of determining distinctly dinosaurian features is that early dinosaurs and other archosaurs from the Late Triassic epoch are often poorly known and were similar in many ways; these animals have sometimes been misidentified in the literature.

Dinosaurs stand with their hind limbs erect in a manner similar to most modern mammals, but distinct from most other reptiles, whose limbs sprawl out to either side. This posture is due to the development of a laterally facing recess in the pelvis (usually an open socket) and a corresponding inwardly facing distinct head on the femur. Their erect posture enabled early dinosaurs to breathe easily while moving, which likely permitted stamina and activity levels that surpassed those of "sprawling" reptiles. Erect limbs probably also helped support the evolution of large size by reducing bending stresses on limbs. Some non-dinosaurian archosaurs, including rauisuchians, also had erect limbs but achieved this by a "pillar-erect" configuration of the hip joint, where instead of having a projection from the femur insert on a socket on the hip, the upper pelvic bone was rotated to form an overhanging shelf.

History of study

Pre-scientific history

Dinosaur fossils have been known for millennia, although their true nature was not recognized. The Chinese considered them to be dragon bones and documented them as such. For example, Huayang Guo Zhi (華陽國志), a gazetteer compiled by Chang Qu (常璩) during the Western Jin Dynasty (265-316), reported the discovery of dragon bones at Wucheng in Sichuan Province. Villagers in central China have long unearthed fossilized "dragon bones" for use in traditional medicines. In Europe, dinosaur fossils were generally believed to be the remains of giants and other biblical creatures.

Early dinosaur research

William Buckland

Scholarly descriptions of what would now be recognized as dinosaur bones first appeared in the late 17th century in England. Part of a bone, now known to have been the femur of a Megalosaurus, was recovered from a limestone quarry at Cornwell near Chipping Norton, Oxfordshire, in 1676. The fragment was sent to Robert Plot, Professor of Chemistry at the University of Oxford and first curator of the Ashmolean Museum, who published a description in his The Natural History of Oxford-shire (1677). He correctly identified the bone as the lower extremity of the femur of a large animal, and recognized that it was too large to belong to any known species. He, therefore, concluded it to be the femur of a huge human, perhaps a Titan or another type of giant featured in legends. Edward Lhuyd, a friend of Sir Isaac Newton, published Lithophylacii Britannici ichnographia (1699), the first scientific treatment of what would now be recognized as a dinosaur when he described and named a sauropod tooth, " Rutellum impicatum", that had been found in Caswell, near Witney, Oxfordshire.

Between 1815 and 1824, the Rev William Buckland, the first Reader of Geology at the University of Oxford, collected more fossilized bones of Megalosaurus and became the first person to describe a non-avian dinosaur in a scientific journal. The second non-avian dinosaur genus to be identified, Iguanodon, was according to legend discovered in 1822 by Mary Ann Mantell - the wife of English geologist Gideon Mantell who in fact had required remains years earlier. Gideon Mantell recognized similarities between his fossils and the bones of modern iguanas. He published his findings in 1825.

The study of these "great fossil lizards" soon became of great interest to European and American scientists, and in 1842 the English paleontologist Sir Richard Owen coined the term "dinosaur", using it to refer to the "distinct tribe or sub-order of Saurian Reptiles" that were then being recognized in England and around the world. The term is derived from Ancient Greek δεινός (deinos) 'terrible, potent or fearfully great', and σαῦρος (sauros) 'lizard or reptile'. Though the taxonomic name has often been interpreted as a reference to dinosaurs' teeth, claws, and other fearsome characteristics, Owen intended it also to evoke their size and majesty. Owen recognized that the remains that had been found so far, Iguanodon, Megalosaurus and Hylaeosaurus, shared distinctive features, and so decided to present them as a distinct taxonomic group. As clarified by British geologist and historian Hugh Torrens, Owen had given a presentation about fossil reptiles to the British Association for the Advancement of Science in 1841, but reports of the time show that Owen did not mention the word "dinosaur", nor recognize dinosaurs as a distinct group of reptiles in his address. He introduced the Dinosauria only in the revised text version of his talk published in April of 1842. With the backing of Prince Albert, the husband of Queen Victoria, Owen established the Natural History Museum, London, to display the national collection of dinosaur fossils and other biological and geological exhibits.

Discoveries in North America

In 1858, William Parker Foulke discovered the first known American dinosaur, in marl pits in the small town of Haddonfield, New Jersey. (Although fossils had been found before, their nature had not been correctly discerned.) The creature was named Hadrosaurus foulkii. It was an extremely important find: Hadrosaurus was one of the first nearly complete dinosaur skeletons found ( the first was in 1834, in Maidstone, England), and it was clearly a bipedal creature. This was a revolutionary discovery as, until that point, most scientists had believed dinosaurs walked on four feet, like other lizards. Foulke's discoveries sparked a wave of interests in dinosaurs in the United States, known as dinosaur mania.

Dinosaur mania was exemplified by the fierce rivalry between Edward Drinker Cope and Othniel Charles Marsh, both of whom raced to be the first to find new dinosaurs in what came to be known as the Bone Wars. This fight between the two scientists lasted for over 30 years, ending in 1897 when Cope died after spending his entire fortune on the dinosaur hunt. Many valuable dinosaur specimens were damaged or destroyed due to the pair's rough methods: for example, their diggers often used dynamite to unearth bones. Modern paleontologists would find such methods crude and unacceptable, since blasting easily destroys fossil and stratigraphic evidence. Despite their unrefined methods, the contributions of Cope and Marsh to paleontology were vast: Marsh unearthed 86 new species of dinosaur and Cope discovered 56, a total of 142 new species. Cope's collection is now at the American Museum of Natural History in New York City, while Marsh's is at the Peabody Museum of Natural History at Yale University.

"Dinosaur renaissance" and beyond

World War II caused a pause in palaeontological research; after the war, research attention was also diverted increasingly to fossil mammals rather than dinosaurs, which were seen as sluggish and cold-blooded. At the end of the 1960s, however, the field of dinosaur research experienced a surge in activity that remains ongoing. Several seminal studies led to this activity. First, John Ostrom discovered the bird-like dromaeosaurid theropod Deinonychus and described it in 1969. Its anatomy indicated that it was an active predator that was likely warm-blooded, in marked contrast to the then-prevailing image of dinosaurs. Concurrently, Robert T. Bakker published a series of studies that likewise argued for active lifestyles in dinosaurs based on anatomical and ecological evidence (see § Physiology), which were subsequently summarized in his 1986 book The Dinosaur Heresies.

Paleontologist Robert T. Bakker with a mounted skeleton of a tyrannosaurid (Gorgosaurus libratus)

New revelations were supported by an increase in dinosaur discoveries. Major new dinosaur discoveries have been made by paleontologists working in previously unexplored regions, including India, South America, Madagascar, Antarctica, and most significantly China. Across theropods, sauropodomorphs, and ornithischians, the number of named genera began to increase exponentially in the 1990s. As of 2008, over 30 new species of dinosaurs were named each year. At least sauropodomorphs experienced a further increase in the number of named species in the 2010s, with an average of 9.3 new species having been named each year between 2009 and 2020. As a consequence, more sauropodomorphs were named between 1990 and 2020 than in all previous years combined. These new localities also led to improvements in overall specimen quality, with new species being increasingly named not on scrappy fossils but on more complete skeletons, sometimes from multiple individuals. Better specimens also led to new species being invalidated less frequently. Asian localities have produced the most complete theropod specimens, while North American localities have produced the most complete sauropodomorph specimens.

Prior to the dinosaur renaissance, dinosaurs were mostly classified using the traditional rank-based system of Linnaean taxonomy. The renaissance was also accompanied by the increasingly widespread application of cladistics, a more objective method of classification based on ancestry and shared traits, which has proved tremendously useful in the study of dinosaur systematics and evolution. Cladistic analysis, among other techniques, helps to compensate for an often incomplete and fragmentary fossil record. Reference books summarizing the state of dinosaur research, such as David B. Weishampel and colleagues' The Dinosauria, made knowledge more accessible and spurred further interest in dinosaur research. The release of the first and second editions of The Dinosauria in 1990 and 2004, and of a review paper by Paul Sereno in 1998, were accompanied by increases in the number of published phylogenetic trees for dinosaurs.

Soft tissue and molecular preservation

Dinosaur fossils are not limited to bones, but also include imprints or mineralized remains of skin coverings, organs, and other tissues. Of these, skin coverings based on keratin proteins are most easily preserved because of their cross-linked, hydrophobic molecular structure. Fossils of keratin-based skin coverings or bony skin coverings are known from most major groups of dinosaurs. Dinosaur fossils with scaly skin impressions have been found since the 19th century. Samuel Beckles discovered a sauropod forelimb with preserved skin in 1852 that was incorrectly attributed to a crocodile; it was correctly attributed by Marsh in 1888 and subject to further study by Reginald Hooley in 1917. Among ornithischians, in 1884 Jacob Wortman found skin impressions on the first known specimen of Edmontosaurus annectens, which were largely destroyed during the specimen's excavation. Owen and Hooley subsequently described skin impressions of Hypsilophodon and Iguanodon in 1885 and 1917. Since then, scale impressions have been most frequently found among hadrosaurids, where the impressions are known from nearly the entire body across multiple specimens.

Starting from the 1990s, major discoveries of exceptionally preserved fossils in deposits known as conservation Lagerstätten contributed to research on dinosaur soft tissues. Chiefly among these were the rocks that produced the Jehol (Early Cretaceous) and Yanliao (Mid-to-Late Jurassic) biotas of northeastern China, from which hundreds of dinosaur specimens bearing impressions of feather-like structures (both closely related to birds and otherwise, see § Origin of birds) have been described by Xing Xu and colleagues. In living reptiles and mammals, pigment-storing cellular structures known as melanosomes are partially responsible for producing colouration. Both chemical traces of melanin and characteristically-shaped melanosomes have been reported from feathers and scales of Jehol and Yanliao dinosaurs, including both theropods and ornithischians. This has enabled multiple full-body reconstructions of dinosaur colouration, such as for Sinosauropteryx and Psittacosaurus by Jakob Vinther and colleagues, and similar techniques have also been extended to dinosaur fossils from other localities. (However, some researchers have also suggested that fossilized melanosomes represent bacterial remains.) Stomach contents in some Jehol and Yanliao dinosaurs closely related to birds have also provided indirect indications of diet and digestive system anatomy (e.g., crops). More concrete evidence of internal anatomy has been reported in from the Pietraroja Plattenkalk of Italy. It preserves portions of the intestines, colon, liver, muscles, and windpipe.

Concurrently, a line of work led by Mary Higby Schweitzer, Jack Horner, and colleagues reported various occurrences of preserved soft tissues and proteins within dinosaur bone fossils. Various mineralized structures that likely represented red blood cells and collagen fibres had been found by Schweitzer and others in tyrannosaurid bones as early as 1991. However, in 2005, Schweitzer and colleagues reported that a femur of Tyrannosaurus preserved soft, flexible tissue within, including blood vessels, bone matrix, and connective tissue (bone fibers) that had retained their microscopic structure. This discovery suggested that original soft tissues could be preserved over geological time, with multiple mechanisms having been proposed. Later, in 2009, Schweitzer and colleagues reported that a Brachylophosaurus femur preserved similar microstructures, and immunohistochemical techniques (based on antibody binding) demonstrated the presence of proteins such as collagen, elastin, and laminin. Both specimens yielded collagen protein sequences that were viable for molecular phylogenetic analyses, which grouped them with birds as would be expected. The extraction of fragmentary DNA has also been reported for both of these fossils, along with a specimen of Hypacrosaurus. In 2015, Sergio Bertazzo and colleagues reported the preservation of collagen fibres and red blood cells in eight Cretaceous dinosaur specimens that did not show any signs of exceptional preservation, indicating that soft tissue may be preserved more commonly than previously thought. Suggestions that these structures represent bacterial biofilms have been rejected, but cross-contamination remains a possibility that is difficult to detect.

Evolutionary history

Origins and early evolution

The early dinosaurs Herrerasaurus (large), Eoraptor (small) and a Plateosaurus skull, from the Triassic

Dinosaurs diverged from their archosaur ancestors during the Middle to Late Triassic epochs, roughly 20 million years after the devastating Permian-Triassic extinction event wiped out an estimated 96% of all marine species and 70% of terrestrial vertebrate species approximately 252 million years ago. The oldest dinosaur fossils known from substantial remains date to the Carnian epoch of the Triassic period and have been found primarily in the Ischigualasto and Santa Maria Formations of Argentina, and the Pebbly Arkose Formation of Zimbabwe.

The Ischigualasto Formation ( radiometrically dated at 231-230 million years old) has produced the early saurischian , originally considered a member of the Herrerasauridae but now considered to be an early sauropodomorph, along with the herrerasaurids Herrerasaurus and Sanjuansaurus, and the sauropodomorphs Chromogisaurus, Eodromaeus, and . Eoraptor's likely resemblance to the common ancestor of all dinosaurs suggests that the first dinosaurs would have been small, bipedal predators. The Santa Maria Formation (radiometrically dated to be older, at 233.23 million years old) has produced the herrerasaurids Gnathovorax and Staurikosaurus, along with the sauropodomorphs Bagualosaurus, Buriolestes, Guaibasaurus, Macrocollum, Nhandumirim, Pampadromaeus, Saturnalia, and Unaysaurus. The Pebbly Arkose Formation, which is of uncertain age but was likely comparable to the other two, has produced the sauropodomorph Mbiresaurus, along with an unnamed herrerasaurid.

Less well-preserved remains of the sauropodomorphs Jaklapallisaurus and , along with the early saurischian Alwalkeria, are known from the Upper Maleri and Lower Maleri Formations of India. The Carnian-aged Chañares Formation of Argentina preserves primitive, dinosaur-like ornithodirans such as Lagosuchus and Lagerpeton in Argentina, making it another important site for understanding dinosaur evolution. These ornithodirans support the model of early dinosaurs as small, bipedal predators. Dinosaurs may have appeared as early as the Anisian epoch of the Triassic, approximately 243 million years ago, which is the age of Nyasasaurus from the Manda Formation of Tanzania. However, its known fossils are too fragmentary to identify it as a dinosaur or only a close relative. The referral of the Manda Formation to the Anisian is also uncertain. Regardless, dinosaurs existed alongside non-dinosaurian ornithodirans for a period of time, with estimates ranging from 5-10 million years to 21 million years.

When dinosaurs appeared, they were not the dominant terrestrial animals. The terrestrial habitats were occupied by various types of archosauromorphs and therapsids, like cynodonts and rhynchosaurs. Their main competitors were the pseudosuchians, such as aetosaurs, ornithosuchids and rauisuchians, which were more successful than the dinosaurs. Most of these other animals became extinct in the Triassic, in one of two events. First, at about 215 million years ago, a variety of basal archosauromorphs, including the protorosaurs, became extinct. This was followed by the Triassic-Jurassic extinction event (about 201 million years ago), that saw the end of most of the other groups of early archosaurs, like aetosaurs, ornithosuchids, phytosaurs, and rauisuchians. Rhynchosaurs and dicynodonts survived (at least in some areas) at least as late as early -mid Norian and late Norian or earliest Rhaetian stages, respectively, and the exact date of their extinction is uncertain. These losses left behind a land fauna of crocodylomorphs, dinosaurs, mammals, pterosaurians, and turtles. The first few lines of early dinosaurs diversified through the Carnian and Norian stages of the Triassic, possibly by occupying the niches of the groups that became extinct. Also notably, there was a heightened rate of extinction during the Carnian pluvial event.

Evolution and paleobiogeography

The supercontinent Pangaea in the early Mesozoic (around 200 million years ago)

Dinosaur evolution after the Triassic followed changes in vegetation and the location of continents. In the Late Triassic and Early Jurassic, the continents were connected as the single landmass Pangaea, and there was a worldwide dinosaur fauna mostly composed of coelophysoid carnivores and early sauropodomorph herbivores. Gymnosperm plants (particularly conifers), a potential food source, radiated in the Late Triassic. Early sauropodomorphs did not have sophisticated mechanisms for processing food in the mouth, and so must have employed other means of breaking down food farther along the digestive tract. The general homogeneity of dinosaurian faunas continued into the Middle and Late Jurassic, where most localities had predators consisting of ceratosaurians, megalosauroids, and allosauroids, and herbivores consisting of stegosaurian ornithischians and large sauropods. Examples of this include the Morrison Formation of North America and Tendaguru Beds of Tanzania. Dinosaurs in China show some differences, with specialized metriacanthosaurid theropods and unusual, long-necked sauropods like Mamenchisaurus. Ankylosaurians and ornithopods were also becoming more common, but primitive sauropodomorphs had become extinct. Conifers and pteridophytes were the most common plants. Sauropods, like earlier sauropodomorphs, were not oral processors, but ornithischians were evolving various means of dealing with food in the mouth, including potential cheek-like organs to keep food in the mouth, and jaw motions to grind food. Another notable evolutionary event of the Jurassic was the appearance of true birds, descended from maniraptoran coelurosaurians.

By the Early Cretaceous and the ongoing breakup of Pangaea, dinosaurs were becoming strongly differentiated by landmass. The earliest part of this time saw the spread of ankylosaurians, iguanodontians, and brachiosaurids through Europe, North America, and northern Africa. These were later supplemented or replaced in Africa by large spinosaurid and carcharodontosaurid theropods, and rebbachisaurid and titanosaurian sauropods, also found in South America. In Asia, maniraptoran coelurosaurians like dromaeosaurids, troodontids, and oviraptorosaurians became the common theropods, and ankylosaurids and early ceratopsians like Psittacosaurus became important herbivores. Meanwhile, Australia was home to a fauna of basal ankylosaurians, hypsilophodonts, and iguanodontians. The stegosaurians appear to have gone extinct at some point in the late Early Cretaceous or early Late Cretaceous. A major change in the Early Cretaceous, which would be amplified in the Late Cretaceous, was the evolution of flowering plants. At the same time, several groups of dinosaurian herbivores evolved more sophisticated ways to orally process food. Ceratopsians developed a method of slicing with teeth stacked on each other in batteries, and iguanodontians refined a method of grinding with dental batteries, taken to its extreme in hadrosaurids. Some sauropods also evolved tooth batteries, best exemplified by the rebbachisaurid Nigersaurus.

There were three general dinosaur faunas in the Late Cretaceous. In the northern continents of North America and Asia, the major theropods were tyrannosaurids and various types of smaller maniraptoran theropods, with a predominantly ornithischian herbivore assemblage of hadrosaurids, ceratopsians, ankylosaurids, and pachycephalosaurians. In the southern continents that had made up the now-splitting supercontinent Gondwana, abelisaurids were the common theropods, and titanosaurian sauropods the common herbivores. Finally, in Europe, dromaeosaurids, rhabdodontid iguanodontians, nodosaurid ankylosaurians, and titanosaurian sauropods were prevalent. Flowering plants were greatly radiating, with the first grasses appearing by the end of the Cretaceous. Grinding hadrosaurids and shearing ceratopsians became very diverse across North America and Asia. Theropods were also radiating as herbivores or omnivores, with therizinosaurians and ornithomimosaurians becoming common.

The Cretaceous-Paleogene extinction event, which occurred approximately 66 million years ago at the end of the Cretaceous, caused the extinction of all dinosaur groups except for the neornithine birds. Some other diapsid groups, including crocodilians, dyrosaurs, sebecosuchians, turtles, lizards, snakes, sphenodontians, and choristoderans, also survived the event.

The surviving lineages of neornithine birds, including the ancestors of modern ratites, ducks and chickens, and a variety of waterbirds, diversified rapidly at the beginning of the Paleogene period, entering ecological niches left vacant by the extinction of Mesozoic dinosaur groups such as the arboreal enantiornithines, aquatic hesperornithines, and even the larger terrestrial theropods (in the form of , eogruiids, bathornithids, ratites, geranoidids, mihirungs, and " terror birds"). It is often stated that mammals out-competed the neornithines for dominance of most terrestrial niches but many of these groups co-existed with rich mammalian faunas for most of the Cenozoic Era. Terror birds and bathornithids occupied carnivorous guilds alongside predatory mammals, and ratites are still fairly successful as mid-sized herbivores; eogruiids similarly lasted from the Eocene to Pliocene, becoming extinct only very recently after over 20 million years of co-existence with many mammal groups.

Classification

Dinosaurs belong to a group known as archosaurs, which also includes modern crocodilians. Within the archosaur group, dinosaurs are differentiated most noticeably by their gait. Dinosaur legs extend directly beneath the body, whereas the legs of lizards and crocodilians sprawl out to either side.

Collectively, dinosaurs as a clade are divided into two primary branches, Saurischia and Ornithischia. Saurischia includes those taxa sharing a more recent common ancestor with birds than with Ornithischia, while Ornithischia includes all taxa sharing a more recent common ancestor with Triceratops than with Saurischia. Anatomically, these two groups can be distinguished most noticeably by their pelvic structure. Early saurischians-"lizard-hipped", from the Greek () meaning "lizard" and () meaning "hip joint"-retained the hip structure of their ancestors, with a pubis bone directed cranially, or forward. This basic form was modified by rotating the pubis backward to varying degrees in several groups ( Herrerasaurus, therizinosauroids, dromaeosaurids, and birds). Saurischia includes the theropods (exclusively bipedal and with a wide variety of diets) and sauropodomorphs (long-necked herbivores which include advanced, quadrupedal groups).

By contrast, ornithischians-"bird-hipped", from the Greek ornitheios (ὀρνίθειος) meaning "of a bird" and ischion (ἰσχίον) meaning "hip joint"-had a pelvis that superficially resembled a bird's pelvis: the pubic bone was oriented caudally (rear-pointing). Unlike birds, the ornithischian pubis also usually had an additional forward-pointing process. Ornithischia includes a variety of species that were primarily herbivores.

Despite the terms "bird hip" (Ornithischia) and "lizard hip" (Saurischia), birds are not part of Ornithischia. Birds instead belong to Saurischia, the "lizard-hipped" dinosaurs-birds evolved from earlier dinosaurs with "lizard hips".

The following is a simplified classification of dinosaur groups based on their evolutionary relationships, and those of the main dinosaur groups Theropoda, Sauropodomorpha and Ornithischia, compiled by Justin Tweet. Further details and other hypotheses of classification may be found on individual articles.

Restoration of six ornithopods; far left: Camptosaurus, left: Iguanodon, center background: Shantungosaurus, center foreground: Dryosaurus, right: Corythosaurus, far right (large) Tenontosaurus.

†Ornithischia ("bird-hipped"; diverse bipedal and quadrupedal herbivores)

†Thyreophora (armored dinosaurs; bipeds and quadrupeds)

†Eurypoda (heavy, quadrupedal thyreophorans)

Restoration of four ceratopsids: top left - Triceratops, top right - Styracosaurus, bottom left - Anchiceratops, bottom right - Chasmosaurus.

†Ornithopoda (various sizes; bipeds and quadrupeds; evolved a method of chewing using skull flexibility and numerous teeth)

†Elasmaria (mostly southern ornithopods with mineralized plates along the ribs; may be thescelosaurids)

†Rhabdodontomorpha (with distinctive dentition)

†Hadrosauriformes (ancestrally had a thumb spike; large quadrupedal herbivores, with teeth merged into dental batteries)

Restoration of four macronarian sauropods: from left to right Camarasaurus, Brachiosaurus, Giraffatitan, and Euhelopus

†Sauropoda (very large and heavy; quadrupedal)

†Diplodocoidea (skulls and tails elongated; teeth typically narrow and pencil-like)

†Macronaria (boxy skulls; spoon- or pencil-shaped teeth)

†Euhelopodidae (stocky, mostly Asian)

†Titanosauria (diverse; stocky, with wide hips; most common in the Late Cretaceous of southern continents)

†Ceratosauria (generally elaborately horned carnivores that existed from the Jurassic to Cretaceous periods, originally included Coelophysoidea)

Coelurosauria (feathered theropods, with a range of body sizes and niches)

†"Nexus of basal coelurosaurs" (used by Tweet to denote well-known taxa with unstable positions at the base of Coelurosauria)

Tyrannoraptora ("tyrant thieves")

†Ornithomimosauria (small-headed, mostly toothless, omnivorous or possible herbivores)

Restoration of six dromaeosaurid theropods: from left to right Microraptor, Velociraptor, Austroraptor, Dromaeosaurus, Utahraptor, and Deinonychus

†Caenagnathidae (toothless oviraptorosaurs known from North America and Asia)

†Oviraptoridae (characterized by two bony projections at the back of the mouth; exclusive to Asia)

Paraves (avialans and their closest relatives)

†Microraptoria (characterized by large wings on both the arms and legs; may have been capable of powered flight)

†Eudromaeosauria (hunters with greatly enlarged sickle claws)

Avialae (modern birds and extinct relatives)

Timeline of major groups

Timeline of major dinosaur groups per Holtz (2007).

Paleobiology

Knowledge about dinosaurs is derived from a variety of fossil and non-fossil records, including fossilized bones, feces, trackways, gastroliths, feathers, impressions of skin, internal organs and other soft tissues. Many fields of study contribute to our understanding of dinosaurs, including physics (especially biomechanics), chemistry, biology, and the Earth sciences (of which paleontology is a sub-discipline). Two topics of particular interest and study have been dinosaur size and behavior.

Scale diagram comparing the average human to the longest known dinosaurs in five major clades:

Current evidence suggests that dinosaur average size varied through the Triassic, Early Jurassic, Late Jurassic and Cretaceous. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100 to kg (220 to lb) category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the 10 to 100 kg (22 to 220 lb) category. The mode of Mesozoic dinosaur body masses is between 1 and 10 metric tons (1.1 and 11.0 short tons). This contrasts sharply with the average size of Cenozoic mammals, estimated by the National Museum of Natural History as about 2 to 5 kg (4.4 to 11.0 lb).

The sauropods were the largest and heaviest dinosaurs. For much of the dinosaur era, the smallest sauropods were larger than anything else in their habitat, and the largest was an order of magnitude more massive than anything else that has since walked the Earth. Giant prehistoric mammals such as Paraceratherium (the largest land mammal ever) were dwarfed by the giant sauropods, and only modern whales approach or surpass them in size. There are several proposed advantages for the large size of sauropods, including protection from predation, reduction of energy use, and longevity, but it may be that the most important advantage was dietary. Large animals are more efficient at digestion than small animals, because food spends more time in their digestive systems. This also permits them to subsist on food with lower nutritive value than smaller animals. Sauropod remains are mostly found in rock formations interpreted as dry or seasonally dry, and the ability to eat large quantities of low-nutrient browse would have been advantageous in such environments.

Largest and smallest

The tallest and heaviest dinosaur known from good skeletons is Giraffatitan brancai (previously classified as a species of Brachiosaurus). Its remains were discovered in Tanzania between 1907 and 1912. Bones from several similar-sized individuals were incorporated into the skeleton now mounted and on display at the Museum für Naturkunde in Berlin; this mount is 12 meters (39 ft) tall and 21.8 to 22.5 meters (72 to 74 ft) long, and would have belonged to an animal that weighed between and kilograms ( and lb). The longest complete dinosaur is the 27 meters (89 ft) long Diplodocus, which was discovered in Wyoming in the United States and displayed in Pittsburgh's Carnegie Museum of Natural History in 1907. The longest dinosaur known from good fossil material is Patagotitan: the skeleton mount in the American Museum of Natural History in New York is 37 meters (121 ft) long. The Museo Municipal Carmen Funes in Plaza Huincul, Argentina, has an Argentinosaurus reconstructed skeleton mount that is 39.7 meters (130 ft) long.

An adult bee hummingbird, the smallest known dinosaur

There were larger dinosaurs, but knowledge of them is based entirely on a small number of fragmentary fossils. Most of the largest herbivorous specimens on record were discovered in the 1970s or later, and include the massive Argentinosaurus, which may have weighed to kilograms (90 to 110 short tons) and reached lengths of 30 to 40 meters (98 to 131 ft); some of the longest were the 33.5-meter (110 ft) long Diplodocus hallorum (formerly Seismosaurus), the 33-to-34-meter (108 to 112 ft) long Supersaurus, and 37-meter (121 ft) long Patagotitan; and the tallest, the 18-meter (59 ft) tall Sauroposeidon, which could have reached a sixth-floor window. The heaviest and longest dinosaur may have been Maraapunisaurus, known only from a now lost partial vertebral neural arch described in 1878. Extrapolating from the illustration of this bone, the animal may have been 58 meters (190 ft) long and weighed kg ( lb). However, as no further evidence of sauropods of this size has been found, and the discoverer, Cope, had made typographic errors before, it is likely to have been an extreme overestimation.

The largest carnivorous dinosaur was Spinosaurus, reaching a length of 12.6 to 18 meters (41 to 59 ft), and weighing 7 to 20.9 metric tons (7.7 to 23.0 short tons). Other large carnivorous theropods included Giganotosaurus, Carcharodontosaurus and Tyrannosaurus. Therizinosaurus and Deinocheirus were among the tallest of the theropods. The largest ornithischian dinosaur was probably the hadrosaurid Shantungosaurus giganteus which measured 16.6 meters (54 ft). The largest individuals may have weighed as much as 16 metric tons (18 short tons).

The smallest dinosaur known is the bee hummingbird, with a length of only 5 centimeters (2.0 in) and mass of around 1.8 g (0.063 oz). The smallest known non- avialan dinosaurs were about the size of pigeons and were those theropods most closely related to birds. For example, Anchiornis huxleyi is currently the smallest non-avialan dinosaur described from an adult specimen, with an estimated weight of 110 g (3.9 oz) and a total skeletal length of 34 centimeters (1.12 ft). The smallest herbivorous non-avialan dinosaurs included Microceratus and Wannanosaurus, at about 60 centimeters (2.0 ft) long each.

Many modern birds are highly social, often found living in flocks. There is general agreement that some behaviors that are common in birds, as well as in crocodiles (closest living relatives of birds), were also common among extinct dinosaur groups. Interpretations of behavior in fossil species are generally based on the pose of skeletons and their habitat, computer simulations of their biomechanics, and comparisons with modern animals in similar ecological niches.

The first potential evidence for herding or flocking as a widespread behavior common to many dinosaur groups in addition to birds was the 1878 discovery of 31 Iguanodon, ornithischians that were then thought to have perished together in Bernissart, Belgium, after they fell into a deep, flooded sinkhole and drowned. Other mass-death sites have been discovered subsequently. Those, along with multiple trackways, suggest that gregarious behavior was common in many early dinosaur species. Trackways of hundreds or even thousands of herbivores indicate that duck-billed (hadrosaurids) may have moved in great herds, like the American bison or the African springbok. Sauropod tracks document that these animals traveled in groups composed of several different species, at least in Oxfordshire, England, although there is no evidence for specific herd structures. Congregating into herds may have evolved for defense, for migratory purposes, or to provide protection for young. There is evidence that many types of slow-growing dinosaurs, including various theropods, sauropods, ankylosaurians, ornithopods, and ceratopsians, formed aggregations of immature individuals. One example is a site in Inner Mongolia that has yielded remains of over 20 Sinornithomimus, from one to seven years old. This assemblage is interpreted as a social group that was trapped in mud. The interpretation of dinosaurs as gregarious has also extended to depicting carnivorous theropods as pack hunters working together to bring down large prey. However, this lifestyle is uncommon among modern birds, crocodiles, and other reptiles, and the taphonomic evidence suggesting mammal-like pack hunting in such theropods as Deinonychus and Allosaurus can also be interpreted as the results of fatal disputes between feeding animals, as is seen in many modern diapsid predators.

The crests and frills of some dinosaurs, like the marginocephalians, theropods and lambeosaurines, may have been too fragile to be used for active defense, and so they were likely used for sexual or aggressive displays, though little is known about dinosaur mating and territorialism. Head wounds from bites suggest that theropods, at least, engaged in active aggressive confrontations.

From a behavioral standpoint, one of the most valuable dinosaur fossils was discovered in the Gobi Desert in 1971. It included a Velociraptor attacking a Protoceratops, providing evidence that dinosaurs did indeed attack each other. Additional evidence for attacking live prey is the partially healed tail of an Edmontosaurus, a hadrosaurid dinosaur; the tail is damaged in such a way that shows the animal was bitten by a tyrannosaur but survived. Cannibalism amongst some species of dinosaurs was confirmed by tooth marks found in Madagascar in 2003, involving the theropod Majungasaurus.

Comparisons between the scleral rings of dinosaurs and modern birds and reptiles have been used to infer daily activity patterns of dinosaurs. Although it has been suggested that most dinosaurs were active during the day, these comparisons have shown that small predatory dinosaurs such as dromaeosaurids, Juravenator, and Megapnosaurus were likely nocturnal. Large and medium-sized herbivorous and omnivorous dinosaurs such as ceratopsians, sauropodomorphs, hadrosaurids, ornithomimosaurs may have been cathemeral, active during short intervals throughout the day, although the small ornithischian Agilisaurus was inferred to be diurnal.

Based on fossil evidence from dinosaurs such as Oryctodromeus, some ornithischian species seem to have led a partially fossorial (burrowing) lifestyle. Many modern birds are arboreal (tree climbing), and this was also true of many Mesozoic birds, especially the enantiornithines. While some early bird-like species may have already been arboreal as well (including dromaeosaurids) such as Microraptor) most non-avialan dinosaurs seem to have relied on land-based locomotion. A good understanding of how dinosaurs moved on the ground is key to models of dinosaur behavior; the science of biomechanics, pioneered by Robert McNeill Alexander, has provided significant insight in this area. For example, studies of the forces exerted by muscles and gravity on dinosaurs' skeletal structure have investigated how fast dinosaurs could run, whether diplodocids could create sonic booms via whip-like tail snapping, and whether sauropods could float.

Communication

Modern birds are known to communicate using visual and auditory signals, and the wide diversity of visual display structures among fossil dinosaur groups, such as horns, frills, crests, sails, and feathers, suggests that visual communication has always been important in dinosaur biology. Reconstruction of the plumage color of Anchiornis, suggest the importance of color in visual communication in non-avian dinosaurs. Vocalization in non-avian dinosaurs is less certain. In birds, the larynx plays no role in sound production. Instead they vocalize with a novel organ called the syrinx, located further down the trachea. The earliest remains of a syrinx was found in a specimen of the duck-like Vegavis iaai dated 69 -66 million years ago, and this organ is unlikely to have existed in non-avian dinosaurs.

Paleontologist Phil Senter has suggested that since non-avian dinosaurs did not have a syrinx, and their next closest living relatives, crocodilians, use the larynx, they could not vocalize as the common ancestor would have been mute. He states that they mostly on visual displays and possibly non-vocal acoustic sounds like hissing, jaw grinding or clapping, splashing and wing beating (possible in winged maniraptoran dinosaurs). Other researchers have countered that vocalizations also exist in turtles, the closest relatives of archosaurs, suggesting that the trait is ancestral to their lineage. In addition, vocal communication in dinosaurs is indicated by the development of advanced hearing in nearly all major groups. Hence the syrinx may have supplemented and then replaced the larynx as a vocal organ rather than there being a "silent period" in bird evolution.

In 2023, a fossilized larynx was described from a specimen of the ankylosaurid Pinacosaurus. The structure was composed of cricoid and arytenoid cartilages, similar to those of non-avian reptiles. However, the mobile cricoid-arytenoid joint and long arytenoid cartilages would have allowed for air-flow control similar to that of birds, and thus could have made bird-like vocalizations. In addition, the cartilages were ossified, implying that laryngeal ossification is a feature of some non-avian dinosaurs. A 2016 study concludes that some dinosaurs may have produced closed mouth vocalizations like cooing, hooting and booming. These occur in both reptiles and birds and involve inflating the esophagus or tracheal pouches. Such vocalizations evolved independently in extant archosaurs numerous times, following increases in body size. The crests of some hadrosaurids and the nasal chambers of ankylosaurids have been suggested to have functioned in acoustic resonance.

Reproductive biology

All dinosaurs laid amniotic eggs. Dinosaur eggs were usually laid in a nest. Most species create somewhat elaborate nests which can be cups, domes, plates, beds scrapes, mounds, or burrows. Some species of modern bird have no nests; the cliff-nesting common guillemot lays its eggs on bare rock, and male emperor penguins keep eggs between their body and feet. Primitive birds and many non-avialan dinosaurs often lay eggs in communal nests, with males primarily incubating the eggs. While modern birds have only one functional oviduct and lay one egg at a time, more primitive birds and dinosaurs had two oviducts, like crocodiles. Some non-avialan dinosaurs, such as , exhibited iterative laying, where the adult might lay a pair of eggs every one or two days, and then ensured simultaneous hatching by delaying brooding until all eggs were laid.

When laying eggs, females grow a special type of bone between the hard outer bone and the marrow of their limbs. This medullary bone, which is rich in calcium, is used to make eggshells. A discovery of features in a Tyrannosaurus skeleton provided evidence of medullary bone in extinct dinosaurs and, for the first time, allowed paleontologists to establish the sex of a fossil dinosaur specimen. Further research has found medullary bone in the carnosaur Allosaurus and the ornithopod Tenontosaurus. Because the line of dinosaurs that includes Allosaurus and Tyrannosaurus diverged from the line that led to Tenontosaurus very early in the evolution of dinosaurs, this suggests that the production of medullary tissue is a general characteristic of all dinosaurs.

Fossil interpreted as a nesting oviraptorid Citipati at the American Museum of Natural History. Smaller fossil far right showing inside one of the eggs.

Another widespread trait among modern birds (but see below in regards to fossil groups and extant megapodes) is parental care for young after hatching. Jack Horner's 1978 discovery of a ("good mother lizard") nesting ground in Montana demonstrated that parental care continued long after birth among ornithopods. A specimen of the oviraptorid Citipati osmolskae was discovered in a chicken-like brooding position in 1993, which may indicate that they had begun using an insulating layer of feathers to keep the eggs warm. An embryo of the basal sauropodomorph Massospondylus was found without teeth, indicating that some parental care was required to feed the young dinosaurs. Trackways have also confirmed parental behavior among ornithopods from the Isle of Skye in northwestern Scotland.

However, there is ample evidence of precociality or superprecociality among many dinosaur species, particularly theropods. For instance, non- ornithuromorph birds have been abundantly demonstrated to have had slow growth rates, megapode-like egg burying behavior and the ability to fly soon after birth. Both Tyrannosaurus and Troodon had juveniles with clear superprecociality and likely occupying different ecological niches than the adults. Superprecociality has been inferred for sauropods.

Genital structures are unlikely to fossilize as they lack scales that may allow preservation via pigmentation or residual calcium phosphate salts. In 2021, the best preserved specimen of a dinosaur's cloacal vent exterior was described for Psittacosaurus, demonstrating lateral swellings similar to crocodylian musk glands used in social displays by both sexes and pigmented regions which could also reflect a signalling function. However, this specimen on its own does not offer enough information to determine whether this dinosaur had sexual signalling functions; it only supports the possibility. Cloacal visual signalling can occur in either males or females in living birds, making it unlikely to be useful to determine sex for extinct dinosaurs.

Physiology

Because both modern crocodilians and birds have four-chambered hearts (albeit modified in crocodilians), it is likely that this is a trait shared by all archosaurs, including all dinosaurs. While all modern birds have high metabolisms and are endothermic ("warm-blooded"), a vigorous debate has been ongoing since the 1960s regarding how far back in the dinosaur lineage this trait extended. Various researchers have supported dinosaurs as being endothermic, ectothermic ("cold-blooded"), or somewhere in between. An emerging consensus among researchers is that, while different lineages of dinosaurs would have had different metabolisms, most of them had higher metabolic rates than other reptiles but lower than living birds and mammals, which is termed mesothermy by some. Evidence from crocodiles and their extinct relatives suggests that such elevated metabolisms could have developed in the earliest archosaurs, which were the common ancestors of dinosaurs and crocodiles.

After non-avian dinosaurs were discovered, paleontologists first posited that they were ectothermic. This was used to imply that the ancient dinosaurs were relatively slow, sluggish organisms, even though many modern reptiles are fast and light-footed despite relying on external sources of heat to regulate their body temperature. The idea of dinosaurs as ectothermic remained a prevalent view until Robert T. Bakker, an early proponent of dinosaur endothermy, published an influential paper on the topic in 1968. Bakker specifically used anatomical and ecological evidence to argue that sauropods, which had hitherto been depicted as sprawling aquatic animals with their tails dragging on the ground, were endotherms that lived vigorous, terrestrial lives. In 1972, Bakker expanded on his arguments based on energy requirements and predator-prey ratios. This was one of the seminal results that led to the dinosaur renaissance.

One of the greatest contributions to the modern understanding of dinosaur physiology has been paleohistology, the study of microscopic tissue structure in dinosaurs. From the 1960s forward, Armand de Ricqlès suggested that the presence of fibrolamellar bone-bony tissue with an irregular, fibrous texture and filled with blood vessels-was indicative of consistently fast growth and therefore endothermy. Fibrolamellar bone was common in both dinosaurs and pterosaurs, though not universally present. This has led to a significant body of work in reconstructing growth curves and modeling the evolution of growth rates across various dinosaur lineages, which has suggested overall that dinosaurs grew faster than living reptiles. Other lines of evidence suggesting endothermy include the presence of feathers and other types of body coverings in many lineages (see § Feathers); more consistent ratios of the isotope oxygen-18 in bony tissue compared to ectotherms, particularly as latitude and thus air temperature varied, which suggests stable internal temperatures (although these ratios can be altered during fossilization); and the discovery of polar dinosaurs, which lived in Australia, Antarctica, and Alaska when these places would have had cool, temperate climates.

Comparison between the air sacs of an abelisaur and a bird

In saurischian dinosaurs, higher metabolisms were supported by the evolution of the avian respiratory system, characterized by an extensive system of air sacs that extended the lungs and invaded many of the bones in the skeleton, making them hollow. Such respiratory systems, which may have appeared in the earliest saurischians, would have provided them with more oxygen compared to a mammal of similar size, while also having a larger resting tidal volume and requiring a lower breathing frequency, which would have allowed them to sustain higher activity levels. The rapid airflow would also have been an effective cooling mechanism, which in conjunction with a lower metabolic rate would have prevented large sauropods from overheating. These traits may have enabled sauropods to grow quickly to gigantic sizes. Sauropods may also have benefitted from their size-their small surface area to volume ratio meant that they would have been able to thermoregulate more easily, a phenomenon termed gigantothermy.

Like other reptiles, dinosaurs are primarily uricotelic, that is, their kidneys extract nitrogenous wastes from their bloodstream and excrete it as uric acid instead of urea or ammonia via the ureters into the intestine. This would have helped them to conserve water. In most living species, uric acid is excreted along with feces as a semisolid waste. However, at least some modern birds (such as hummingbirds) can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. This material, as well as the output of the intestines, emerges from the cloaca. In addition, many species regurgitate pellets, and fossil pellets are known as early as the Jurassic from Anchiornis.

The size and shape of the brain can be partly reconstructed based on the surrounding bones. In 1896, Marsh calculated ratios between brain weight and body weight of seven species of dinosaurs, showing that the brain of dinosaurs was proportionally smaller than in today's crocodiles, and that the brain of Stegosaurus was smaller than in any living land vertebrate. This contributed to the widespread public notion of dinosaurs as being sluggish and extraordinarily stupid. Harry Jerison, in 1973, showed that proportionally smaller brains are expected at larger body sizes, and that brain size in dinosaurs was not smaller than expected when compared to living reptiles. Later research showed that relative brain size progressively increased during the evolution of theropods, with the highest intelligence - comparable to that of modern birds - calculated for the troodontid Troodon.

Origin of birds

The possibility that dinosaurs were the ancestors of birds was first suggested in 1868 by Thomas Henry Huxley. After the work of Gerhard Heilmann in the early 20th century, the theory of birds as dinosaur descendants was abandoned in favor of the idea of them being descendants of generalized thecodonts, with the key piece of evidence being the supposed lack of clavicles in dinosaurs. However, as later discoveries showed, clavicles (or a single fused wishbone, which derived from separate clavicles) were not actually absent; they had been found as early as 1924 in , but misidentified as an interclavicle. In the 1970s, Ostrom revived the dinosaur-bird theory, which gained momentum in the coming decades with the advent of cladistic analysis, and a great increase in the discovery of small theropods and early birds. Of particular note have been the fossils of the Jehol Biota, where a variety of theropods and early birds have been found, often with feathers of some type. Birds share over a hundred distinct anatomical features with theropod dinosaurs, which are now generally accepted to have been their closest ancient relatives. They are most closely allied with maniraptoran coelurosaurs. A minority of scientists, most notably Alan Feduccia and Larry Martin, have proposed other evolutionary paths, including revised versions of Heilmann's basal archosaur proposal, or that maniraptoran theropods are the ancestors of birds but themselves are not dinosaurs, only convergent with dinosaurs.

Various feathered non-avian dinosaurs, including Archaeopteryx, Anchiornis, Microraptor and Zhenyuanlong

Feathers are one of the most recognizable characteristics of modern birds, and a trait that was also shared by several non-avian dinosaurs. Based on the current distribution of fossil evidence, it appears that feathers were an ancestral dinosaurian trait, though one that may have been selectively lost in some species. Direct fossil evidence of feathers or feather-like structures has been discovered in a diverse array of species in many non-avian dinosaur groups, both among saurischians and ornithischians. Simple, branched, feather-like structures are known from heterodontosaurids, primitive neornithischians, and theropods, and primitive ceratopsians. Evidence for true, vaned feathers similar to the flight feathers of modern birds has been found only in the theropod subgroup Maniraptora, which includes oviraptorosaurs, troodontids, dromaeosaurids, and birds. Feather-like structures known as pycnofibres have also been found in pterosaurs.

However, researchers do not agree regarding whether these structures share a common origin between lineages (i.e., they are homologous), or if they were the result of widespread experimentation with skin coverings among ornithodirans. If the former is the case, filaments may have been common in the ornithodiran lineage and evolved before the appearance of dinosaurs themselves. Research into the genetics of American alligators has revealed that crocodylian scutes do possess feather-keratins during embryonic development, but these keratins are not expressed by the animals before hatching. The description of feathered dinosaurs has not been without controversy in general; perhaps the most vocal critics have been Alan Feduccia and Theagarten Lingham-Soliar, who have proposed that some purported feather-like fossils are the result of the decomposition of collagenous fiber that underlaid the dinosaurs' skin, and that maniraptoran dinosaurs with vaned feathers were not actually dinosaurs, but convergent with dinosaurs. However, their views have for the most part not been accepted by other researchers, to the point that the scientific nature of Feduccia's proposals has been questioned.

Archaeopteryx was the first fossil found that revealed a potential connection between dinosaurs and birds. It is considered a transitional fossil, in that it displays features of both groups. Brought to light just two years after Charles Darwin's seminal On the Origin of Species (1859), its discovery spurred the nascent debate between proponents of evolutionary biology and creationism. This early bird is so dinosaur-like that, without a clear impression of feathers in the surrounding rock, at least one specimen was mistaken for the small theropod Compsognathus. Since the 1990s, a number of additional feathered dinosaurs have been found, providing even stronger evidence of the close relationship between dinosaurs and modern birds. Many of these specimens were unearthed in the lagerstätten of the Jehol Biota. If feather-like structures were indeed widely present among non-avian dinosaurs, the lack of abundant fossil evidence for them may be due to the fact that delicate features like skin and feathers are seldom preserved by fossilization and thus often absent from the fossil record.

Because feathers are often associated with birds, feathered dinosaurs are often touted as the missing link between birds and dinosaurs. However, the multiple skeletal features also shared by the two groups represent another important line of evidence for paleontologists. Areas of the skeleton with important similarities include the neck, pubis, wrist (semi-lunate carpal), arm and pectoral girdle, furcula (wishbone), and breast bone. Comparison of bird and dinosaur skeletons through cladistic analysis strengthens the case for the link.

Soft anatomy

Large meat-eating dinosaurs had a complex system of air sacs similar to those found in modern birds, according to a 2005 investigation led by Patrick M. O'Connor. The lungs of theropod dinosaurs (carnivores that walked on two legs and had bird-like feet) likely pumped air into hollow sacs in their skeletons, as is the case in birds. "What was once formally considered unique to birds was present in some form in the ancestors of birds", O'Connor said. In 2008, scientists described Aerosteon riocoloradensis, the skeleton of which supplies the strongest evidence to date of a dinosaur with a bird-like breathing system. CT scanning of Aerosteon' s fossil bones revealed evidence for the existence of air sacs within the animal's body cavity.

Behavioral evidence

Fossils of the troodonts and Sinornithoides demonstrate that some dinosaurs slept with their heads tucked under their arms. This behavior, which may have helped to keep the head warm, is also characteristic of modern birds. Several deinonychosaur and oviraptorosaur specimens have also been found preserved on top of their nests, likely brooding in a bird-like manner. The ratio between egg volume and body mass of adults among these dinosaurs suggest that the eggs were primarily brooded by the male, and that the young were highly precocial, similar to many modern ground-dwelling birds.

Extinction of major groups

All non-avian dinosaurs and most lineages of birds became extinct in a mass extinction event, called the Cretaceous-Paleogene (K-Pg) extinction event, at the end of the Cretaceous period. Above the Cretaceous-Paleogene boundary, which has been dated to 66.038 ± 0.025 million years ago, fossils of non-avian dinosaurs disappear abruptly; the absence of dinosaur fossils was historically used to assign rocks to the ensuing Cenozoic. The nature of the event that caused this mass extinction has been extensively studied since the 1970s, leading to the development of two mechanisms that are thought to have played major roles: an extraterrestrial impact event in the Yucatán Peninsula, along with flood basalt volcanism in India. However, the specific mechanisms of the extinction event and the extent of its effects on dinosaurs are still areas of ongoing research. Alongside dinosaurs, many other groups of animals became extinct: pterosaurs, marine reptiles such as mosasaurs and plesiosaurs, several groups of mammals, ammonites ( nautilus-like mollusks), rudists ( reef-building bivalves), and various groups of marine plankton. In all, approximately 47% of genera and 76% of species on Earth became extinct during the K-Pg extinction event. The relatively large size of most dinosaurs and the low diversity of small-bodied dinosaur species at the end of the Cretaceous may have contributed to their extinction; the extinction of the bird lineages that did not survive may also have been caused by a dependence on forest habitats or a lack of adaptations to eating seeds for survival.

Pre-extinction diversity

Just before the K-Pg extinction event, the number of non-avian dinosaur species that existed globally has been estimated at between 628 and 1078. It remains uncertain whether the diversity of dinosaurs was in gradual decline before the K-Pg extinction event, or whether dinosaurs were actually thriving prior to the extinction. Rock formations from the Maastrichtian epoch, which directly preceded the extinction, have been found to have lower diversity than the preceding Campanian epoch, which led to the prevailing view of a long-term decline in diversity. However, these comparisons did not account either for varying preservation potential between rock units or for different extents of exploration and excavation. In 1984, Dale Russell carried out an analysis to account for these biases, and found no evidence of a decline; another analysis by David Fastovsky and colleagues in 2004 even showed that dinosaur diversity continually increased until the extinction, but this analysis has been rebutted. Since then, different approaches based on statistics and mathematical models have variously supported either a sudden extinction or a gradual decline. End-Cretaceous trends in diversity may have varied between dinosaur lineages: it has been suggested that sauropods were not in decline, while ornithischians and theropods were in decline.

Impact event

The bolide impact hypothesis, first brought to wide attention in 1980 by Walter Alvarez, Luis Alvarez, and colleagues, attributes the K-Pg extinction event to a bolide (extraterrestrial projectile) impact. Alvarez and colleagues proposed that a sudden increase in iridium levels, recorded around the world in rock deposits at the Cretaceous-Paleogene boundary, was direct evidence of the impact. Shocked quartz, indicative of a strong shockwave emanating from an impact, was also found worldwide. The actual impact site remained elusive until a crater measuring 180 km (110 mi) wide was discovered in the Yucatán Peninsula of southeastern Mexico, and was publicized in a 1991 paper by Alan Hildebrand and colleagues. Now, the bulk of the evidence suggests that a bolide 5 to 15 kilometers (3 to miles) wide impacted the Yucatán Peninsula 66 million years ago, forming this crater and creating a "kill mechanism" that triggered the extinction event.

Within hours, the Chicxulub impact would have created immediate effects such as earthquakes, tsunamis, and a global firestorm that likely killed unsheltered animals and started wildfires. However, it would also have had longer-term consequences for the environment. Within days, sulfate aerosols released from rocks at the impact site would have contributed to acid rain and ocean acidification. Soot aerosols are thought to have spread around the world over the ensuing months and years; they would have cooled the surface of the Earth by reflecting thermal radiation, and greatly slowed photosynthesis by blocking out sunlight, thus creating an impact winter. (This role was ascribed to sulfate aerosols until experiments demonstrated otherwise.) The cessation of photosynthesis would have led to the collapse of food webs depending on leafy plants, which included all dinosaurs save for grain-eating birds.

Deccan Traps

At the time of the K-Pg extinction, the Deccan Traps flood basalts of India were actively erupting. The eruptions can be separated into three phases around the K-Pg boundary, two prior to the boundary and one after. The second phase, which occurred very close to the boundary, would have extruded 70 to 80% of the volume of these eruptions in intermittent pulses that occurred around 100,000 years apart. Greenhouse gases such as carbon dioxide and sulfur dioxide would have been released by this volcanic activity, resulting in climate change through temperature perturbations of roughly 3 °C (5.4 °F) but possibly as high as 7 °C (13 °F). Like the Chicxulub impact, the eruptions may also have released sulfate aerosols, which would have caused acid rain and global cooling. However, due to large error margins in the dating of the eruptions, the role of the Deccan Traps in the K-Pg extinction remains unclear.

Before 2000, arguments that the Deccan Traps eruptions-as opposed to the Chicxulub impact-caused the extinction were usually linked to the view that the extinction was gradual. Prior to the discovery of the Chicxulub crater, the Deccan Traps were used to explain the global iridium layer; even after the crater's discovery, the impact was still thought to only have had a regional, not global, effect on the extinction event. In response, Luis Alvarez rejected volcanic activity as an explanation for the iridium layer and the extinction as a whole. Since then, however, most researchers have adopted a more moderate position, which identifies the Chicxulub impact as the primary progenitor of the extinction while also recognizing that the Deccan Traps may also have played a role. Walter Alvarez himself has acknowledged that the Deccan Traps and other ecological factors may have contributed to the extinctions in addition to the Chicxulub impact. Some estimates have placed the start of the second phase in the Deccan Traps eruptions within 50,000 years after the Chicxulub impact. Combined with mathematical modelling of the seismic waves that would have been generated by the impact, this has led to the suggestion that the Chicxulub impact may have triggered these eruptions by increasing the permeability of the mantle plume underlying the Deccan Traps.

Whether the Deccan Traps were a major cause of the extinction, on par with the Chicxulub impact, remains uncertain. Proponents consider the climatic impact of the sulfur dioxide released to have been on par with the Chicxulub impact, and also note the role of flood basalt volcanism in other mass extinctions like the Permian-Triassic extinction event. They consider the Chicxulub impact to have worsened the ongoing climate change caused by the eruptions. Meanwhile, detractors point out the sudden nature of the extinction and that other pulses in Deccan Traps activity of comparable magnitude did not appear to have caused extinctions. They also contend that the causes of different mass extinctions should be assessed separately. In 2020, Alfio Chiarenza and colleagues suggested that the Deccan Traps may even have had the opposite effect: they suggested that the long-term warming caused by its carbon dioxide emissions may have dampened the impact winter from the Chicxulub impact.

Possible Paleocene survivors

Non-avian dinosaur remains have occasionally been found above the K-Pg boundary. In 2000, Spencer Lucas and colleagues reported the discovery of a single hadrosaur right femur in the San Juan Basin of New Mexico, and described it as evidence of Paleocene dinosaurs. The rock unit in which the bone was discovered has been dated to the early Paleocene epoch, approximately 64.8 million years ago. If the bone was not re-deposited by weathering action, it would provide evidence that some dinosaur populations survived at least half a million years into the Cenozoic. Other evidence includes the presence of dinosaur remains in the Hell Creek Formation up to 1.3 m (4.3 ft) above the Cretaceous-Paleogene boundary, representing 40,000 years of elapsed time. This has been used to support the view that the K-Pg extinction was gradual. However, these supposed Paleocene dinosaurs are considered by many other researchers to be reworked, that is, washed out of their original locations and then re-buried in younger sediments. The age estimates have also been considered unreliable.

Cultural depictions

Gertie the Dinosaur (1914) by Winsor McCay, featuring the first animated dinosaur

Public enthusiasm for dinosaurs first developed in Victorian England, where in 1854, three decades after the first scientific descriptions of dinosaur remains, a menagerie of lifelike dinosaur sculptures was unveiled in London's Crystal Palace Park. The Crystal Palace dinosaurs proved so popular that a strong market in smaller replicas soon developed. In subsequent decades, dinosaur exhibits opened at parks and museums around the world, ensuring that successive generations would be introduced to the animals in an immersive and exciting way. The enduring popularity of dinosaurs, in its turn, has resulted in significant public funding for dinosaur science, and has frequently spurred new discoveries. In the United States, for example, the competition between museums for public attention led directly to the Bone Wars of the 1880s and 1890s, during which a pair of feuding paleontologists made enormous scientific contributions.

The popular preoccupation with dinosaurs has ensured their appearance in literature, film, and other media. Beginning in 1852 with a passing mention in Charles Dickens' Bleak House, dinosaurs have been featured in large numbers of fictional works. Jules Verne's 1864 novel Journey to the Center of the Earth, Sir Arthur Conan Doyle's 1912 book The Lost World, the 1914 animated film Gertie the Dinosaur (featuring the first animated dinosaur), the iconic 1933 film , the 1954 and its many sequels, the best-selling 1990 novel Jurassic Park by Michael Crichton and its 1993 film adaptation are just a few notable examples of dinosaur appearances in fiction. Authors of general-interest non-fiction works about dinosaurs, including some prominent paleontologists, have often sought to use the animals as a way to educate readers about science in general. Dinosaurs are ubiquitous in advertising; numerous companies have referenced dinosaurs in printed or televised advertisements, either in order to sell their own products or in order to characterize their rivals as slow-moving, dim-witted, or obsolete.

Further reading

University of Southampton (September 29, 2021). "Two New Species of Large Predatory Dinosaur With Crocodile-Like Skulls Discovered on Isle of Wight". SciTechDaily.

Zhou, Zhonghe (October 2004). "The origin and early evolution of birds: discoveries, disputes, and perspectives from fossil evidence" (PDF). Naturwissenschaften. Berlin: Springer Science+Business Media. 91 (10): 455-471. Bibcode:2004NW.....91..455Z. doi:10.1007/s00114-004-0570-4. ISSN 0028-1042. PMID 15365634. S2CID 3329625. Archived from the original (PDF) on July 21, 2011.

Paul, Gregory S. (2002). Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore; London: Johns Hopkins University Press. ISBN 978-0-8018-6763-7. LCCN 2001000242. OCLC 1088130487..

Stewart, Tabori & Chang (1997). The Humongous Book of Dinosaurs. New York: Stewart, Tabori & Chang. ISBN 978-1-55670-596-0. LCCN 97000398. OCLC 1037269801.

Sternberg, Charles Mortram (1966) [Original edition published by E. Cloutier, printer to the King, 1946]. Canadian Dinosaurs. Geological Series. Vol. 54 (2nd ed.). Ottawa: National Museum of Canada. LCCN gs46000214. OCLC 1032865683.

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References

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Ethica Wines | Italian Roots. Global Reach.

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Monoculture vs. polyculture: It’s all about “passion” in the vineyard, says Aleš Kristančič of Movia - Ethica Wines | Italian Roots. Global Reach.

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Aleš Kristančič from Movia winery, one of the world’s most respected natural winemakers, explains monoculture vs. polyculture.

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In agriculture, polyculture is the practice of growing more than one crop species together in the same place at the same time, in contrast to monoculture, which had become the dominant approach in developed countries by 1950. Traditional examples include the intercropping of the Three Sisters, namely maize, beans, and squashes, by indigenous peoples of Central and North America, the rice-fish systems of Asia, and the complex mixed cropping systems of Nigeria.

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Circular economy: definition, importance and benefits | Topics | European Parliament

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The circular economy: find out what it means, how it benefits you, the environment and our economy.

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Transshipment of Dogs and Cats via Hong Kong

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  Adobe Acrobat e-Form
 
Import Requirements
Please read the permit terms carefully to ensure the full compliance before importation of animals. Failure to comply with the Permit Terms may render the animals to be returned to the country / place of export or quarantined for a period determined by the Senior Veterinary Officer at the cost and risk of the permittee / agent. The permittee / agent may be prosecuted.
The animals must not remain in Hong Kong for more than 24 hours unless prior approval is granted. Immediate onward transshipment must be carried out before the end of that period. Transshipment Origin
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DC-10v04
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Please comply with the requirements of the country / place of destination  
Transshipment of Dogs and Cats via Hong Kong Permit must be obtained in advance for animal transshipment (involving change of aircraft or mode of transport in Hong Kong).
If the animals remain in the same aircraft or vessel, and do not involve the removal from such aircraft or vessel, no Permit is required. However, importers must fully comply with the requirements imposed by the country / place of destination. Please click the image below for a summary of the importation procedure. I. Submit the application document: Fill in the prescribed form (Form No. AF240 & Form No. UN110) or Form No. AF301 for animals from the Mainland China. Facsimile copies are available from the interactive telephone (852) 2708 8885. The form can also be obtained by dialing (852) 1823.
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If the destination after Hong Kong is Macau, the permittee must produce a copy of the valid Macau Import Permit (Authorizacao) for inspection before export to Macau. The animals must be transported to Macau by an approved means of conveyance. II. Pay the Permit Fee
Fee must be paid at the time of the application (unless otherwise stated). Permit fee for a single animal is HK$432. Fee for each additional animal is HK$102 under a same permit for a single shipment.
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To avoid postal delay, the applicant may choose to pick up the permit at the licensing office in person or by an appointed agent. The permit will not be dispatched by fax nor email. VI. Validity of Permit Valid for 6 months and for one consignment only. Animals must be imported on or before the expiry date of the permit.
If extension is required, application and fee must be submitted before the permit expired.
The permit will only be extended for 30 days in every application, and it takes 3 working days for the extension process from the date of receipt of application and fee.   Important Reminder Final travel arrangement should NOT be made until a permit has been granted. Two sets of carbonised Special Permits will be sent to the applicant. Please retain the original (white) copy for the retrieval of pets on arrival. The carrying airline and shipping company may require the shipper to produce the duplicate (yellow) copy before accepting the carriage of pets in the exporting country/place. Pets that have left Hong Kong are subject to the importation and quarantine restrictions as outlined above on their return to Hong Kong. Special Permits/Import Permits to bring back pets that have left Hong Kong need to be obtained from this Department in advance. If deemed necessary (for instance, animals of doubtful history; animals showing clinical signs of diseases), the quarantine period for dogs and cats from all countries/places (Group I, II and IIIA and IIIB) may be extended. Dogs and cats without proper documentation may be required to undertake a minimum of 4-month quarantine at the owner’s expense or returned to the country/place of origin. Location of AFCD office at the Hong Kong International Airport.   Enquiry
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Mosasaurus

Reconstructed skeleton of M. hoffmannii at the Maastricht Natural History Museum

Scientific classification

Kingdom:

Animalia

Phylum:

Chordata

Class:

Reptilia

Order:

Squamata

Superfamily:

† Mosasauroidea

Family:

† Mosasauridae

Tribe:

† Mosasaurini

Genus:

† Mosasaurus
Conybeare, 1822

Type species

†Mosasaurus hoffmannii

Other species

Species pending reassessment

†M. mokoroa Welles & Gregg, 1971

†M. hobetsuensis Suzuki, 1985

†M. flemingi Wiffen, 1990

Sakurai †M. prismaticus et al., 1999

Synonyms

Batrachiosaurus Harlan, 1839

Batrachiotherium Harlan, 1839

Macrosaurus Owen, 1849

Drepanodon Leidy, 1856

Lesticodus Leidy, 1859

Baseodon Leidy, 1865

Nectoportheus Cope, 1868

Pterycollosaurus Dollo, 1882

Lacerta gigantea von Sömmerring, 1820

Mososaurus hoffmannii Mantell, 1829

Mosasaurus belgicus Holl, 1829

Mosasaurus camperi Meyer, 1832

Mosasaurus dekayi Bronn, 1838

Mosasaurus hoffmanni Owen, 1840

Mosasaurus major De Kay, 1842

Mosasaurus occidentalis Morton, 1844

Mosasaurus meirsii Marsh, 1869

Mosasaurus princeps Marsh, 1869

Mosasaurus maximus Cope, 1869

Mosasaurus giganteus Cope, 1869

Mosasaurus fulciatus Cope, 1869

Mosasaurus oarthus Cope, 1869

Synonyms of M. missouriensis[9][10]

Ichthyosaurus missouriensis Harlan, 1834

Ictiosaurus missuriensis Harlan, 1834

Batrachiosaurus missouriensis Harlan, 1839

Batrachiotherium missouriensis Harlan, 1839

Mosasaurus maximiliani Goldfuss, 1845

Mosasaurus neovidii Meyer, 1845

Pterycollosaurus maximiliani Dollo, 1882

Mosasaurus horridus Williston, 1895

Synonyms of M. conodon[11]

Clidastes conodon Cope, 1881

Mosasaurus (; "lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The earliest fossils of Mosasaurus known to science were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, which were initially thought to have been the bones of crocodiles or whales. One skull discovered around 1780, which was seized by France during the French Revolutionary Wars for its scientific value, was famously nicknamed the "great animal of Maastricht". In 1808, naturalist Georges Cuvier concluded that it belonged to a giant marine lizard with similarities to monitor lizards but otherwise unlike any known living animal. This concept was revolutionary at the time and helped support the then-developing ideas of extinction. Cuvier did not designate a scientific name for the new animal, and this was done by William Daniel Conybeare in 1822 when he named it Mosasaurus in reference to its origin in fossil deposits near the Meuse River. The exact affinities of Mosasaurus as a squamate remain controversial, and scientists continue to debate whether its closest living relatives are monitor lizards or snakes.

Traditional interpretations have estimated the maximum length of the largest species, M. hoffmannii, to be up to 17.1 meters (56 ft), making it one of the largest mosasaurs, although some scientists consider this an overestimation with recent estimates suggesting a length closer to 13 meters (43 ft). The skull of Mosasaurus was equipped with robust jaws capable of swinging back and forth and strong muscles capable of powerful bites using dozens of large teeth adapted for cutting prey. Its four limbs were shaped into robust paddles to steer the animal underwater. Its tail was long and ended in a downward bend and a paddle-like fluke. Mosasaurus was a predator possessing excellent vision to compensate for its poor sense of smell, and a high metabolic rate suggesting it was endothermic ("warm-blooded"), an adaptation only found in mosasaurs among squamates. There is considerable morphological variability across the currently-recognized species in Mosasaurus-from the robustly-built M. hoffmannii to the slender and serpentine M. lemonnieri-but an unclear diagnosis (description of distinguishing features) of the type species M. hoffmannii led to a historically problematic classification. As a result, more than fifty different species have been attributed to the genus in the past. A redescription of the type specimen in 2017 helped resolve the taxonomy issue and confirmed at least five species to be within the genus. Another five species still nominally classified within Mosasaurus are planned to be reassessed in a future study.

Fossil evidence suggests Mosasaurus inhabited much of the Atlantic Ocean and the seaways adjacent to it. Mosasaurus fossils have been found in places as diverse as North and South America, Europe, Africa, Western Asia, and Antarctica. This distribution encompassed a wide range of oceanic climates including tropical, subtropical, temperate, and subpolar climates. Mosasaurus was a common large predator in these oceans and was positioned at the top of the food chain. Paleontologists believe its diet would have included virtually any animal; it likely preyed on bony fish, sharks, cephalopods, birds, and other marine reptiles including sea turtles and other mosasaurs. It likely preferred to hunt in open water near the surface. From an ecological standpoint, Mosasaurus probably had a profound impact on the structuring of marine ecosystems; its arrival in some locations such as the Western Interior Seaway in North America coincides with a complete turnover of faunal assemblages and diversity. Mosasaurus faced competition with other large predatory mosasaurs such as Prognathodon and Tylosaurus-which were known to feed on similar prey-though they were able to coexist in the same ecosystems through niche partitioning. There were still conflicts among them, as an instance of Tylosaurus attacking a Mosasaurus has been documented. Several fossils document deliberate attacks on Mosasaurus individuals by members of the same species. In fighting likely took place in the form of snout grappling, similarly seen in modern crocodiles today.

The first Mosasaurus fossil known to science was discovered in 1764 in a chalk quarry near Maastricht in the Netherlands in the form of a skull, which was initially identified as a whale. Later around 1780, the quarry produced a second skull that caught the attention of the physician Johann Leonard Hoffmann, who thought it was a crocodile. He contacted the prominent biologist Petrus Camper, and the skull gained international attention after Camper published a study identifying it as a whale. This caught the attention of French revolutionaries, who looted the fossil following the capture of Maastricht during the French Revolutionary Wars in 1794. In a 1798 narrative of this event by Barthélemy Faujas de Saint-Fond, the skull was allegedly retrieved by twelve grenadiers in exchange for an offer of 600 bottles of wine. This story helped elevate the fossil into cultural fame, but historians agree that the narrative was exaggerated.

After its seizure, the second skull was sent to the National Museum of Natural History, France in 1795 and later cataloged as MNHN AC 9648. By 1808, Camper's son Adriaan Gilles Camper and Georges Cuvier concluded that the fossil, which by then was nicknamed the "great animal of Maastricht", belonged to a marine lizard with affinities to monitor lizards, but otherwise unlike any modern animal. The skull became part of Cuvier's first speculations about the conception of extinction, which later led to his theory of catastrophism, a precursor to the theory of evolution. At the time, it was not believed that a species could go extinct, and fossils of animals were often interpreted as some form of an extant species. Cuvier's idea that there existed an animal unlike any today was revolutionary at the time, and in 1812 he proclaimed, "Above all, the precise determination of the famous animal from Maastricht seems to us as important for the theory of zoological laws, as for the history of the globe." In a 1822 work by James Parkinson, William Daniel Conybeare coined the genus Mosasaurus from the Latin Mosa " Meuse" and the Ancient Greek σαῦρος ( saûros, "lizard"), all literally meaning "lizard of the Meuse", in reference to the river where the holotype specimen was discovered nearby. In 1829, Gideon Mantell added the specific epithet hoffmannii, in honor to Hoffmann. Cuvier later designated the second skull as the new species' holotype (defining example).

In 1804, the Lewis and Clark Expedition discovered a now-lost fossil skeleton alongside the Missouri River, which was identified as a 45-foot (14 m) long fish. Richard Ellis speculated in 2003 that this may have been the earliest discovery of the second species M. missouriensis, although competing speculations exist. In 1818, a fossil from Monmouth County, New Jersey became the first North American specimen to be correctly recognized as a Mosasaurus by scientists of the time.

The type specimen of M. missouriensis was first described in 1834 by Richard Harlan based on a snout fragment found along the river's Big Bend. He coined the specific epithet and initially identified it as a species of Ichthyosaurus but later as an amphibian. The rest of the skull had been discovered earlier by a fur-trapper, and it eventually came under the possession of prince Maximilian of Weid-Neuwied between 1832 and 1834. The fossil was delivered to Georg August Goldfuss in Bonn for research, who published a study in 1845. The same year, Christian Erich Hermann von Meyer suspected that the skull and Harlan's snout were part of the same individual. This was confirmed in 2004.

The third species was described in 1881 from fragmentary fossils in New Jersey by Edward Drinker Cope, who thought it was a giant species of and named it Clidastes conodon. In 1966, it was reidentified as a species of Mosasaurus. In his description, Cope does not provide the etymology for the specific epithet conodon, but it is suggested that it could be a portmanteau meaning "conical tooth", derived from the Ancient Greek κῶνος ( kônos, "cone") and ὀδών ( odṓn, "tooth"), probably in reference to conical surface teeth smooth of the species.

The fourth species M. lemonnieri was first detected by Camper Jr. based on fossils from his father's collections, which he discussed with Cuvier during their 1799 correspondence, but Cuvier rejected the idea of another Mosasaurus species. This species was re-introduced to science and formally described in 1889 by Louis Dollo based on a skull recovered by Alfred Lemonnier from a phosphate quarry in Belgium. Dollo names the species in his honor. Further mining of the quarry in subsequent years uncovered many additional well-preserved fossils, including multiple partial skeletons which collectively represented nearly the entire skeleton of the species. They were described by Dollo in later papers. Despite being the best anatomically represented species, M. lemonnieri was largely ignored in scientific literature. Theagarten Lingham-Soliar suggested two reasons for this neglect. First, M. lemonnieri fossils are endemic to Belgium and the Netherlands, which despite the famous discovery of the M. hoffmannii holotype attracted little attention from mosasaur paleontologists. Second, the species was overshadowed by the more famous and history-rich type species.

M. lemonnieri is a controversial taxon, and there is debate on whether it is a distinct species or not. In 1967, Dale Russell argued that M. lemonnieri and M. conodon are the same species and designated the former as a junior synonym per the principle of priority. In a 2000 study, Lingham-Soliar refuted this based on a comprehensive study of existing M. lemonnieri specimens, which was corroborated by a study on the M. conodon skull by Takehito Ikejiri and Spencer G. Lucas in 2014. In 2004, Eric Mulder, Dirk Cornelissen, and Louis Verding suggested M. lemonnieri could be a juvenile form of M. hoffmannii based on the argument that significant differences could be explained by age-based variation. However, the need for more research to confirm any hypotheses of synonymy was expressed.

The fifth species M. beaugei was described by Camille Arambourg in 1952 from isolated teeth originating from phosphate deposits in the Oulad Abdoun Basin and the Ganntour Basin in Morocco. The species is named in honor of Alfred Beaugé, director at the time of the OCP Group, who invited Arambourg to participate in the research project and helped him to provide local fossils.

Scientists during the early and mid-1800s initially imagined Mosasaurus as an amphibious marine reptile with webbed feet and limbs for walking. This was based on fossils like the M. missouriensis holotype, which indicated an elastic vertebral column that Goldfuss in 1845 saw as evidence of an ability to walk and interpretations of some phalanges as claws. In 1854, Hermann Schlegel proved how Mosasaurus actually had fully aquatic flippers. He clarified that earlier interpretations of claws were erroneous and demonstrated how the phalanges show no indication of muscle or tendon attachment, which would make walking impossible. They are also broad, flat, and form a paddle. Schlegel's hypothesis was largely ignored by contemporary scientists but became widely accepted by the 1870s when Othniel Charles Marsh and Cope uncovered more complete mosasaur remains in North America.

One of the earliest depictions of Mosasaurus in paleoart is a life-size concrete sculpture created by Benjamin Waterhouse Hawkins between 1852 and 1854 as part of the collection of sculptures of prehistoric animals on display at the Crystal Palace Park in London. The restoration was primarily informed by Richard Owen's interpretation of the M. hoffmannii holotype and the anatomy of monitor lizards, so Hawkins depicted the animal as essentially a water-going monitor lizard. It was given a boxy head, nostrils at the side of the skull, large volumes of soft tissue around the eyes, lips reminiscent of monitor lizards, scales consistent with those in large monitors like the Komodo dragon, and a flipper. The model was deliberately sculpted incomplete, which Mark Witton believed was likely to save time and money. Many elements of the sculpture can be considered inaccurate, even for the time. It did not take into account Golduss' 1845 study of M. missouriensis which instead called for a narrower skull, nostrils at the top of the skull, and amphibious terrestrial limbs (the latter being incorrect in modern standards).

Mosasaurus was a type of derived mosasaur, or a latecoming member with advanced evolutionary traits such as a fully aquatic lifestyle. As such, it had a streamlined body, an elongated tail ending with a downturn supporting a two-lobed fin, and two pairs of flippers. While in the past derived mosasaurs were depicted as akin to giant flippered sea snakes, it is now understood that they were more similar in build to other large marine vertebrates such as ichthyosaurs, marine crocodylomorphs, and archaeocete whales through convergent evolution.

The type species, M. hoffmannii, is one of the largest marine reptiles known, though knowledge of its skeleton remains incomplete as it is mainly known from skulls. Russell (1967) wrote that the length of the jaw equalled one tenth of the body length in the species. Based on this ratio, Grigoriev (2014) used the largest lower jaw attributed to M. hoffmannii (CCMGE 10/2469, also known as the Penza specimen; measuring 171 centimeters (67 in) in length) to estimate a maximum length of 17.1 meters (56 ft). Using a smaller partial jaw ( NHMM 009002) measuring 90 centimeters (35 in) and "reliably estimated at" 160 centimeters (63 in) when complete, Lingham-Soliar (1995) estimated a larger maximum length of 17.6 meters (58 ft) via the same ratio. No explicit justification for the 1:10 ratio was provided in Russell (1967), and it has been considered to be probably overestimated by Cleary et al. (2018). In 2014, Federico Fanti and colleagues alternatively argued that the total length of M. hoffmannii was more likely closer to seven times the length of the skull, which was based on a near-complete skeleton of the related species Prognathodon overtoni. The study estimated that an M. hoffmannii individual with a skull measuring more than 145 cm (57 in) would have been up to or more than 11 meters (36 ft) in length and weighed 10 metric tons (11 short tons) in body mass. Mentioning the Penza specimen, Gregory S. Paul estimated in his 2022 book, The Princeton Field Guide to Mesozoic Sea Reptiles, a shorter maximum length for M. hoffmannii of 13 meters (43 ft) and a body mass of 5.5 metric tons (6.1 short tons).

Isolated bones suggest some M. hoffmannii may have exceeded the lengths of the Penza specimen. One such bone is a quadrate (NHMM 003892) which is 150% larger than the average size, which Everhart and colleagues in 2016 reported can be extrapolated to scale an individual around 18 meters (59 ft) in length. It was not stated whether they applied Russell's 1967 ratio.

M. missouriensis and M. lemonnieri are smaller than M. hoffmannii but are known from more complete fossils. Based on measurements of various Belgian skeletons, Dollo estimated M. lemonnieri grew to around 7 to 10 meters (23 to 33 ft) in length. He also measured the dimensions of IRSNB 3119 and recorded that the skull constituted approximately one-eleventh of the whole body. Paul (2022) offered a larger maximum estimate for the species at 12 meters (39 ft) in length and 4.5 metric tons (5.0 short tons) in body mass. Polcyn et al. (2014) estimated that M. missouriensis may have measured up to 8-9 meters (26-30 ft) in length. Street (2016) noted that large M. missouriensis individuals typically had skulls exceeding lengths of 1 meter (3.3 ft). A particular near-complete skeleton of M. missouriensis is reportedly measured at 6.5 meters (21 ft) in total length with a skull approaching 1 meter (3.3 ft) in length.; Paul (2022) estimated an individual of that size to weigh 700 kilograms (1,500 lb). Based on personal observations of various unpublished fossils from Morocco, Nathalie Bardet estimated that M. beaugei grew to a total length of 8-10 meters (26-33 ft), their skulls typically measuring around 1 meter (3.3 ft) in length, with a body mass of around 1.5 metric tons (1.7 short tons) per Paul (2022). With a skull measuring around 97.7 centimeters (38.5 in) in length, M. conodon has been regarded as a small to medium-sized representative of the genus; Paul (2022) estimated its maximum length as being 7 m (23 ft) and body mass as being 900 kg (2,000 lb).

The skull of Mosasaurus is conical and tapers off to a short snout which extends a little beyond the frontmost teeth. In M. hoffmannii, this snout is blunt, while in M. lemonnieri it is pointed. Above the gum line in both jaws, a single row of small pits known as foramina are lined parallel to the jawline; they are used to hold the terminal branches of jaw nerves. The foramina along the snout form a pattern similar to the foramina in Clidastes skulls. The upper jaws in most species are robustly built, broad, and deep except in M. conodon, where they are slender. The disparity is also reflected in the dentary, the lower jawbone, although all species share a long and straight dentary. In M. hoffmannii, the top margin of the dentary is slightly curved upwards; this is also the case with the largest specimens of M. lemonnieri, although more typical skulls of the species have a near-perfectly straight jawline. The premaxillary bar, the long portion of the premaxillary bone extending behind the premaxillary teeth, is narrow and constricts near the middle in M. hoffmannii and M. lemonnieri like in typical mosasaurs. In M. missouriensis, the bar is robust and does not constrict. The external nares ( nostril openings) are moderately sized and measure around 21-24% of the skull's length in M. hoffmannii. They are placed further toward the back of the skull than in nearly all other mosasaurs (exceeded only by Goronyosaurus), and begin above the fourth or fifth maxillary teeth. As a result, the rear portions of the maxilla (the main tooth-bearing bone of the upper jaw) lack the dorsal concavity that would fit the nostrils in typical mosasaurs.

The palate, which consists of the pterygoid bones, palatine bone, and nearby processes of other bones, is tightly packed to provide greater cranial stability. The neurocranium housed a brain which was narrow and relatively small compared to other mosasaurs. For example, the braincase of the mosasaur Plioplatecarpus marshi provided for a brain around twice the size of that in M. hoffmannii despite being only half the length of the latter. Spaces within the braincase for the occipital lobe and cerebral hemisphere are narrow and shallow, suggesting such brain parts were relatively small. The parietal foramen in Mosasaurus, which is associated with the parietal eye, is the smallest among mosasaurids. The quadrate bone, which connected the lower jaw to the rest of the skull and formed the jaw joint, is tall and somewhat rectangular in shape, differing from the rounder quadrates found in typical mosasaurs. The quadrate also housed the hearing structures, with the eardrum residing within a round and concave depression in the outer surface called the tympanic ala. The trachea likely stretched from the esophagus to below the back end of the lower jaw's coronoid process, where it split into smaller pairs of bronchi which extended parallel to each other.

The features of teeth in Mosasaurus vary across species, but unifying characteristics include a design specialized for cutting prey, highly prismatic surfaces (enamel circumference shaped by flat sides called prisms), and two opposite cutting edges. Mosasaurus teeth are large and robust except for those in M. conodon and M. lemonnieri, which instead have more slender teeth. The cutting edges of Mosasaurus differ by species. The cutting edges in M. hoffmannii and M. missouriensis are finely serrated, while in M. conodon and M. lemonnieri serrations do not exist. The cutting edges of M. beaugei are neither serrated nor smooth, but instead possess minute wrinkles known as crenulations. The number of prisms in Mosasaurus teeth can slightly vary between tooth types and general patterns differ between species- M. hoffmannii had two to three prisms on the labial side (the side facing outwards) and no prisms on the lingual side (the side facing the tongue), M. missouriensis had four to six labial prisms and eight lingual prisms, M. lemonnieri had eight to ten labial prisms, and M. beaugei had three to five labial prisms and eight to nine lingual prisms.

Like all mosasaurs, Mosasaurus had four types of teeth, classified based on the jaw bones they were located on. On the upper jaw, there were three types: the premaxillary teeth, maxillary teeth, and pterygoid teeth. On the lower jaw, only one type, the dentary teeth, were present. In each jaw row, from front to back, Mosasaurus had: two premaxillary teeth, twelve to sixteen maxillary teeth, and eight to sixteen pterygoid teeth on the upper jaw and fourteen to seventeen dentary teeth on the lower jaw. The teeth were largely consistent in size and shape with only minor differences throughout the jaws ( homodont) except for the smaller pterygoid teeth. The number of teeth in the maxillae, pterygoids, and dentaries vary between species and sometimes even individuals- M. hoffmannii had fourteen to sixteen maxillary teeth, fourteen to fifteen dentary teeth, and eight pterygoid teeth; M. missouriensis had fourteen to fifteen maxillary teeth, fourteen to fifteen dentary teeth, and eight to nine pterygoid teeth; M. conodon had fourteen to fifteen maxillary teeth, sixteen to seventeen dentary teeth, and eight pterygoid teeth; M. lemonnieri had fifteen maxillary teeth, fourteen to seventeen dentary teeth, and eleven to twelve pterygoid teeth; and M. beaugei had twelve to thirteen maxillary teeth, fourteen to sixteen dentary teeth, and six or more pterygoid teeth. One indeterminate specimen of Mosasaurus similar to M. conodon from the Pembina Gorge State Recreation Area in North Dakota was found to have an unusual count of sixteen pterygoid teeth, far greater than in known species.

The dentition was thecodont (tooth roots deeply cemented within the jaw bone). Teeth were constantly shed through a process where the replacement tooth developed within the root of the original tooth and then pushed it out of the jaw. Chemical studies conducted on a M. hoffmannii maxillary tooth measured an average rate of deposition of odontoblasts, the cells responsible for the formation of dentin, at 10.9 micrometers (0.00043 in) per day. This was by observing the von Ebner lines, incremental marks in dentin that form daily. It was approximated that it took the odontoblasts 511 days and dentin 233 days to develop to the extent observed in the tooth.

One of the most complete Mosasaurus skeletons in terms of vertebral representation ( Mosasaurus sp.; SDSM 452) has seven cervical (neck) vertebrae, thirty-eight dorsal vertebrae (which includes thoracic and lumbar vertebrae) in the back, and eight pygal vertebrae (front tail vertebrae lacking haemal arches) followed by sixty-eight caudal vertebrae in the tail. All species of Mosasaurus have seven cervical vertebrae, but other vertebral counts vary among them. Various partial skeletons of M. conodon, M. hoffmannii, and M. missouriensis suggest M. conodon likely had up to thirty-six dorsal vertebrae and nine pygal vertebrae; M. hoffmannii had likely up to thirty-two dorsal vertebrae and ten pygal vertebrae; and M. missouriensis around thirty-three dorsal vertebrae, eleven pygal vertebrae, and at least seventy-nine caudal vertebrae. M. lemmonieri had the most vertebrae in the genus, with up to around forty dorsal vertebrae, twenty-two pygal vertebrae, and ninety caudal vertebrae. Compared to other mosasaurs, the rib cage of Mosasaurus is unusually deep and forms an almost perfect semicircle, giving it a barrel-shaped chest. Rather than being fused together, extensive cartilage likely connected the ribs with the sternum, which would have facilitated breathing movements and compression when in deeper waters. The texture of the bones is virtually identical with in modern whales, which indicates Mosasaurus possessed a high range of aquatic adaptation and neutral buoyancy as seen in cetaceans.

The tail structure of Mosasaurus is similar to relatives like Prognathodon, in which soft tissue evidence for a two-lobed tail is known. The tail vertebrae gradually shorten around the center of the tail and lengthen behind the center, suggesting rigidness around the tail center and excellent flexibility behind it. Like most advanced mosasaurs, the tail bends slightly downwards as it approached the center, but this bend is offset from the dorsal plane at a small degree. Mosasaurus also has large haemal arches located at the bottom of each caudal vertebra which bend near the middle of the tail, which contrasts with the reduction of haemal arches in other marine reptiles such as ichthyosaurs. These and other features support a large and powerful paddle-like fluke in Mosasaurus.

The forelimbs of Mosasaurus are wide and robust. The scapula and humerus are fan-shaped and wider than tall. The radius and ulna are short, but the former is taller and larger than the latter. The ilium is rod-like and slender; in M. missouriensis, it is around 1.5 times longer than the femur. The femur itself is about twice as long as it is wide and ends at the distal side in a pair of distinct articular facets (of which one connects to the ilium and the other to the paddle bones) that meet at an angle of approximately 120°. Five sets of metacarpals and phalanges (finger bones) were encased in and supported the paddles, with the fifth set being shorter and offset from the rest. The overall structure of the paddle is compressed, similar to in Plotosaurus, and was well-suited for faster swimming. In the hindlimbs, the paddle is supported by four sets of digits.

Interactive skeletal reconstruction of M. hoffmannii
(hover over or click on each skeletal component to identify the structure)

Because nomenclatural rules were not well-defined at the time, 19th century scientists did not give Mosasaurus a proper diagnosis during its initial descriptions, which led to ambiguity in how the genus is defined. This led Mosasaurus to become a wastebasket taxon containing as many as fifty different species. A 2017 study by Hallie Street and Michael Caldwell performed the first proper diagnosis and description of the M. hoffmannii holotype, which allowed a major taxonomic cleanup confirming five species as likely valid- M. hoffmannii, M. missouriensis, M. conodon, M. lemonnieri, and M. beaugei. The study also held four additional species from Pacific deposits- M. mokoroa, M. hobetsuensis, M. flemingi, and M. prismaticus-to be possibly valid, pending a future formal reassessment. Street & Caldwell (2017) was derived from Street's 2016 doctoral thesis, which contained a phylogenetic study proposing the constraining of Mosasaurus into four species- M. hoffmannii, M. missouriensis, M. lemonnieri, and a proposed new species -with M. conodon and the Pacific taxa belonging to different genera and M. beaugei being a synonym of M. hoffmannii.

As the type genus of the family Mosasauridae and the subfamily Mosasaurinae, Mosasaurus is a member of the order Squamata (which comprises lizards and snakes). Relationships between mosasaurs and living squamates remain controversial as scientists still fiercely debate on whether the closest living relatives of mosasaurs are monitor lizards or snakes. Mosasaurus, along with mosasaur genera Eremiasaurus, Plotosaurus, and Moanasaurus traditionally form a tribe within the Mosasaurinae variously called Mosasaurini or Plotosaurini.

One of the earliest relevant attempts at an evolutionary study of Mosasaurus was done by Russell in 1967. He proposed that Mosasaurus evolved from a Clidastes-like mosasaur, and diverged into two lineages, one giving rise to M. conodon and another siring a chronospecies sequence which contained in order of succession M. ivoensis, M. missouriensis, and M. maximus-hoffmanni. However, Russell used an early method of phylogenetics and did not use cladistics.

In 1997, Bell published the first cladistical study of North American mosasaurs. Incorporating the species M. missouriensis, M. conodon, M. maximus, and an indeterminate specimen ( UNSM 77040), some of his findings agreed with Russell (1967), such as Mosasaurus descending from an ancestral group containing Clidastes and M. conodon being the most basal of the genus. Contrary to Russell (1967), Bell also recovered Mosasaurus in a sister relationship with another group which included and Prognathodon, and M. maximus as a sister species to Plotosaurus. The latter rendered Mosasaurus paraphyletic (an unnatural grouping), but Bell (1997) nevertheless recognized Plotosaurus as a distinct genus.

Bell's study served as a precedent for later studies that mostly left the systematics of Mosasaurus unchanged, although some later studies have recovered the sister group to Mosasaurus and Plotosaurus to instead be Eremiasaurus or Plesiotylosaurus depending on the method of data interpretation used, with at least one study also recovering M. missouriensis to be the most basal species of the genus instead of M. conodon. In 2014, Konishi and colleagues expressed a number of concerns with the reliance on Bell's study. First, the genus was severely underrepresented by incorporating only the three North American species M. hoffmannii/M. maximus, M. missouriensis, and M. conodon; by doing so, others like M. lemonnieri, which is one of the most completely known species in the genus, were neglected, which affected phylogenetic results. Second, the studies relied on an unclean and shaky taxonomy of the Mosasaurus genus due to the lack of a clear holotype diagnosis, which may have been behind the genus's paraphyletic status. Third, there was still a lack of comparative studies of the skeletal anatomy of large mosasaurines at the time. These problems were addressed in Street's 2016 thesis in an updated phylogenetic analysis.

Conrad uniquely used only M. hoffmannii and M. lemonnieri in his 2008 phylogenetic analysis, which recovered M. hoffmannii as basal to a multitude of descendant clades containing (in order of most to least basal) Globidens, M. lemonnieri, Goronyosaurus, and Plotosaurus. This result indicated that M. hoffmannii and M. lemonnieri are not in the same genus. However, the study used a method unorthodox to traditional phylogenetic studies on mosasaur species because its focus was on the relationships of entire squamate groups rather than mosasaur classification. As a result, some paleontologists caution that lower-order classification results from Conrad's 2008 study such as the specific placement of Mosasaurus may contain technical problems, making them inaccurate.

The following cladogram on the left (Topology A) is modified from a maximum clade credibility tree inferred by a Bayesian analysis in the most recent major phylogenetic analysis of the Mosasaurinae subfamily by Madzia & Cau (2017), which was self-described as a refinement of a larger study by Simões et al. (2017). The cladogram on the right (Topology B) is modified from Street's 2016 doctoral thesis proposing a revision to the Mosasaurinae, with proposed new taxa and renamings in single quotations.

Positions of groups

Positions of individual taxa

Species traditionally referred as Mosasaurus conodon

Species traditionally referred as Plotosaurus bennisoni

In 1995, Lingham-Soliar studied the head musculature of M. hoffmannii. Because soft tissue like muscles do not easily fossilize, reconstruction of the musculature was largely based on the structure of the skull, muscle scarring on the skull, and the musculature in extant monitor lizards.

In modern lizards, the mechanical build of the skull is characterized by a four-pivot geometric structure in the cranium that allows flexible movement of the jaws, possibly to allow the animals to better position them and prevent prey escape when hunting. In contrast, the frontal and parietal bones, which in modern lizards connect to form a flexible pivot point, overlap in the skull of M. hoffmannii. This creates a rigid three-pivot geometric cranial structure. These cranial structures are united by strong interlocking sutures formed to resist compression and shear forces caused by a downward thrust of the lower jaw muscles or an upward thrust of prey. This rigid but highly shock-absorbent structure of the cranium likely allowed a powerful bite force.

Like all mosasaurs, the lower jaws of Mosasaurus could swing forward and backward. In many mosasaurs like Prognathodon and M. lemonnieri, this function mainly served to allow ratchet feeding, in which the pterygoid and jaws would "walk" captured prey into the mouth like a conveyor belt. But especially compared to those in M. lemonnieri, the pterygoid teeth in M. hoffmannii are relatively small, which indicates ratchet feeding was relatively unimportant to its hunting and feeding. Rather, M. hoffmannii likely employed inertial feeding (in which the animal thrusts its head and neck backward to release a held prey item and immediately thrust the head and neck forward to close the jaws around the item) and used jaw adduction to assist in biting during prey seizure. The magnus adductor muscles, which attach to the lower jaws to the cranium and have a major role in biting function, are massive, indicating M. hoffmannii was capable of enormous bite forces. The long, narrow, and heavy nature of the lower jaws and attachment of tendons at the coronoid process would have allowed quick opening and closing of the mouth with little energy input underwater, which also contributed to the powerful bite force of M. hoffmannii and suggests it would not have needed the strong magnus depressor muscles (jaw-opening muscles) seen in some plesiosaurs.

Mosasaurus swam using its tail. The swimming style was likely sub-carangiform, which is exemplified today by mackerels. Its elongated paddle-like limbs functioned as hydrofoils for maneuvering the animal. The paddles' steering function was enabled by large muscle attachments from the outwards-facing side of the humerus to the radius and ulna and modified joints allowed an enhanced ability of rotating the flippers. The powerful forces resulting from utilization of the paddles may have sometimes resulted in bone damage, as evidenced by a M. hoffmannii ilium with significant separation of the bone's head from the rest of the bone likely caused by frequent shearing forces at the articulation joint.

The tissue structure of Mosasaurus' bones suggests it had a metabolic rate much higher than modern squamates and its resting metabolic rate was between that of the leatherback sea turtle and that of ichthyosaurs and plesiosaurs. Mosasaurus was likely endothermic and maintained a constant body temperature independent of the external environment. Although there is no direct evidence specific to the genus, studies on the biochemistry of related mosasaur genera such as Clidastes suggests that endothermy was likely present in all mosasaurs. Such a trait is unique among squamates, the only known exception being the Argentine black and white tegu, which can maintain partial endothermy. This adaptation would have given several advantages to Mosasaurus, including increased stamina when foraging across larger areas and pursuing prey. It may have also been a factor that allowed Mosasaurus to thrive in the colder climates of locations such as Antarctica.

Mosasaurus had relatively large eye sockets with large sclerotic rings occupying much of the sockets' diameter; the latter is correlated with eye size and suggests it had good vision. The eye sockets were located at the sides of the skull, which created a narrow field of binocular vision at around 28.5° but alternatively allowed excellent processing of a two-dimensional environment, such as the near-surface waters inhabited by Mosasaurus.

Brain casts made from fossils of Mosasaurus show that the olfactory bulb and vomeronasal organ, which both control the function of smell, are poorly developed and lack some structures in M. hoffmannii; this indicates the species had a poor sense of smell. In M. lemonnieri, these olfactory organs, although still small, are better developed and have some components lacking in M. hoffmannii. The lack of a strong sense of smell suggests that olfaction was not particularly important in Mosasaurus; instead, other senses like vision may have been more useful.

Paleontologists generally agree that Mosasaurus was likely an active predator of a variety of marine animals. Fauna likely preyed upon by the genus include bony fish, sharks, cephalopods, birds, and marine reptiles such as other mosasaurs and turtles. It is unlikely Mosasaurus was a scavenger as it had a poor sense of smell. Mosasaurus was among the largest marine animals of its time, and with its large, robust cutting teeth, scientists believe larger members of the genus would have been able to handle virtually any animal. Lingham-Soliar (1995) suggested that Mosasaurus had a rather "savage" feeding behavior as demonstrated by large tooth marks on scutes of the giant sea turtle Allopleuron hoffmanni and fossils of re-healed fractured jaws in M. hoffmannii. The species likely hunted near the ocean surface as an ambush predator, using its large two-dimensionally adapted eyes to more effectively spot and capture prey. Chemical and structural data in the fossils of M. lemonnieri and M. conodon suggests they may have also hunted in deeper waters.

Carbon isotope studies on fossils of multiple M. hoffmannii individuals have found extremely low values of , the lowest in all mosasaurs for the largest individuals. Mosasaurs with lower δ ¹³C values tended to occupy higher trophic levels, and one factor for this was dietary: a diet of prey rich in lipids such as sea turtles and other large marine reptiles can lower δ ¹³C values. M. hoffmannii's low δ ¹³ C levels reinforces its likely position as an apex predator.

Currently, there is only one known example of a Mosasaurus preserved with stomach contents: a well-preserved partial skeleton of a small M. missouriensis dated about 75 million years old with dismembered and punctured remains of a 1 meter (3.3 ft) long fish in its gut. This fish was much longer than the length of the mosasaur's skull, which measured 66 centimeters (26 in) in length, confirming that M. missouriensis consumed prey larger than its head by dismembering and consuming bits at a time. Due coexistence with other large mosasaurs like Prognathodon, which specialized in robust prey, M. missouriensis likely specialized more on prey best consumed using cutting-adapted teeth in an example of niche partitioning.

Mosasaurus may have taught their offspring how to hunt, as supported by a fossil nautiloid Argonautilus catarinae with bite marks from two conspecific mosasaurs, one being from a juvenile and the other being from an adult. Analysis of the tooth marks by a 2014 study by Kauffman concluded that the mosasaurs were either Mosasaurus or Platecarpus. The positioning of both bite marks are at the direction the nautiloid's head would have been facing, indicating it was incapable of escaping and was thus already sick or dead during the attacks; it is possible this phenomenon was from a parent mosasaur teaching its offspring about cephalopods as an alternate source of prey and how to hunt one. An alternate explanation postulates the bite marks as from one individual mosasaur that lightly bit the nautiloid at first, then proceeded to bite again with greater force. However, there are differences in tooth spacing between both bites which indicate different jaw sizes.

There is fossil evidence that Mosasaurus engaged in aggressive and lethal combat with others of its kind. One partial skeleton of M. conodon bears multiple cuts, breaks, and punctures on various bones, particularly in the rear portions of the skull and neck, and a tooth from another M. conodon piercing through the quadrate bone. No injuries on the fossil show signs of healing, suggesting that the mosasaur was killed by its attacker by a fatal blow in the skull. Likewise, an M. missouriensis skeleton has a tooth from another M. missouriensis embedded in the lower jaw underneath the eye. In this case, there were signs of healing around the wound, implying survival of the incident. Takuya Konishi suggested an alternative cause of this example being head-biting behavior during courtship as seen in modern lizards.

Attacks by another Mosasaurus are a possible cause of physical pathologies in other skulls, but they could have instead arisen from other incidents like attempted biting on hard turtle shells. In 2004, Lingham-Soliar observed that if these injuries were indeed the result of an intraspecific attack, then there is a pattern of them concentrating in the skull region. Modern crocodiles commonly attack each other by grappling an opponent's head using their jaws, and Lingham-Soliar hypothesized that Mosasaurus employed similar head-grappling behavior during intraspecific combat. Many of the fossils with injuries possibly attributable to intraspecific combat are of juvenile or sub-adult Mosasaurus, leading to the possibility that attacks on smaller, weaker individuals may have been more common. However, the attacking mosasaurs of the M. conodon and M. missouriensis specimens were likely similar in size to the victims. In 2006, Schulp and colleagues speculated that Mosasaurus may have occasionally engaged in cannibalism as a result of intraspecific aggression.

There are some M. hoffmannii jaws with evidence of infectious diseases as a result of physical injuries. Two examples include IRSNB R25 and IRSNB R27, both having fractures and other pathologies in their dentaries. IRSNB R25 preserves a complete fracture near the sixth tooth socket. Extensive amounts of bony callus almost overgrowing the tooth socket are present around the fracture along with various osteolytic cavities, abscess canals, damages to the trigeminal nerve, and inflamed erosions signifying severe bacterial infection. There are two finely ulcerated scratches on the bone callus, which may have developed as part of the healing process. IRSNB R27 has two fractures: one had almost fully healed and the other is an open fracture with nearby teeth broken off as a result. The fracture is covered with a nonunion formation of bony callus with shallow scratch marks and a large pit connected to an abscess canal. Lingham-Soliar described this pit as resembling a tooth mark from a possible attacking mosasaur. Both specimens show signs of deep bacterial infection alongside the fractures; some bacteria may have spread to nearby damaged teeth and caused tooth decay, which may have entered deeper tissue from prior post-traumatic or secondary infections. The dentaries ahead of the fractures in both specimens are in good condition, suggesting that the arteries and trigeminal nerves had not been damaged; if they were, those areas would have necrotized due to lack of blood. The dentaries' condition suggests that the species may have had an efficient process of immobilizing the fracture during healing, which helped prevent damage to vital blood vessels and nerves. This, along with signs of healing, indicates that the fractures were not imminently fatal.

In 2006, Schulp and colleagues published a study describing a quadrate of M. hoffmannii with multiple unnatural openings and an estimated 0.5 liters (0.13 U.S. gal) of tissue destroyed. This was likely a severe bone infection initiated by septic arthritis, which progressed to the point where a large portion of the quadrate was reduced to abscess. Extensive amounts of bone reparative tissue were also present, suggesting the infection and subsequent healing process may have progressed for a few months. This level of bone infection would have been tremendously painful and severely hampered the mosasaur's ability to use its jaws. The location of the infection may have also interfered with breathing. Considering how the individual was able to survive such conditions for an extended period of time, Schulp and colleagues speculated it switched to a foraging-type diet of soft-bodied prey like squid that could be swallowed whole to minimize jaw use. The cause of the infection remains unknown, but if it were a result of an intraspecific attack then it is possible one of the openings on the quadrate may have been the point of entry for an attacker's tooth from which the infection entered.

Avascular necrosis has been reported by many studies to be present in every examined specimen of M. lemonnieri and M. conodon. In examinations of M. conodon fossils from Alabama and New Jersey and M. lemonnieri fossils from Belgium, Rothschild and Martin in 2005 observed that the condition affected between 3-17% of the vertebrae in the mosasaurs' spines. Avascular necrosis is a common result of decompression illness; it involves bone damage caused by the formation of nitrogen bubbles from inhaled air decompressed during frequent deep-diving trips, or by intervals of repetitive diving and short breathing. This indicates that both Mosasaurus species may have either been habitual deep-divers or repetitive divers. Agnete Weinreich Carlsen considered it the simplest explanation that such conditions were a product of inadequate anatomical adaptation. Nevertheless, fossils of other mosasaurs with invariable avascular necrosis still exhibit substantial adaptations like eardrums that were well-protected from rapid changes in pressure.

Unnatural fusion of tail vertebrae has been documented in Mosasaurus, which occurs when the bones remodel themselves after damage from trauma or disease. A 2015 study by Rothschild and Everhart surveyed 15 Mosasaurus specimens from North America and Belgium and found cases of fused tail vertebrae in three of them. Two of these cases displayed irregular surface deformities around the fusion site caused by drainage of the vertebral sinuses, which is indicative of a bone infection. The causes of such infections are uncertain, but records of fused vertebrae in other mosasaurs suggest attacks by sharks and other predators as a possible candidate. The third case was determined to be caused by a form of arthritis based on the formation of smooth bridging between fused vertebrae.

It is likely that Mosasaurus was viviparous (giving live birth) like most modern mammals today. There is no evidence for live birth in Mosasaurus itself, but it is known in a number of other mosasaurs; examples include a skeleton of a pregnant Carsosaurus, a Plioplatecarpus fossil associated with fossils of two mosasaur embryos, and fossils of newborn Clidastes from pelagic (open ocean) deposits. Such fossil records, along with a total absence of any evidence suggesting external egg-based reproduction, indicates the likeliness of viviparity in Mosasaurus. Microanatomical studies on bones of juvenile Mosasaurus and related genera have found that their bone structures are comparable to adults. They do not exhibit the bone mass increase found in juvenile primitive mosasauroids to support buoyancy associated with a lifestyle in shallow water, implying that Mosasaurus was precocial: they were already efficient swimmers and lived fully functional lifestyles in open water at a very young age, and did not require nursery areas to raise their young. Some areas in Europe and South Dakota have yielded concentrated assemblages of juvenile M. hoffmannii, M. missouriensis and/or M. lemonnieri. These localities are all shallow ocean deposits, suggesting that juvenile Mosasaurus may still have lived in shallow waters.

Distribution, ecosystem, and ecological impact

Mosasaurus had a transatlantic distribution, with its fossils having been found in marine deposits on both sides of the Atlantic Ocean. These localities include the Midwest and East Coast of the United States, Canada, Europe, Turkey, Russia, the Levant, the African coastline from Morocco to South Africa, Brazil, Argentina, and Antarctica. During the Late Cretaceous, these regions made up the three seaways inhabited by Mosasaurus: the Atlantic Ocean, the Western Interior Seaway, and the Mediterranean Tethys. Multiple oceanic climate zones encompassed the seaways, including tropical, subtropical, temperate, and subpolar climates. The wide range of oceanic climates yielded a large diversity of fauna that coexisted with Mosasaurus.

The Mediterranean Tethys during the Maastrichtian stage was located in what is now Europe, Africa, and the Middle East. In recent studies, the confirmation of paleogeographical affinities extended this range to areas across the Atlantic including Brazil and the East Coast state of New Jersey. It is geographically subdivided into two biogeographic provinces that respectively include the northern and southern Tethyan margins. The two mosasaurs Mosasaurus and Prognathodon appear to have been the dominant taxa, being widespread and ecologically diversified throughout the seaway.

The northern Tethyan margin was located around the paleolatitudes of 30- 40°N, consisting of what is now the European continent, Turkey, and New Jersey. At the time, Europe was a scattering of islands with most of the modern continental landmass being underwater. The margin provided a warm-temperate climate with habitats dominated by mosasaurs and sea turtles. M. hoffmannii and Prognathodon sectorius were the dominant species in the northern province. In certain areas such as Belgium, other Mosasaurus species like M. lemonnieri were instead the dominant species, where it's occurrences greatly outnumber those of other large mosasaurs. Other mosasaurs found in the European side of the northern Tethyan margin include smaller genera such as Halisaurus, Plioplatecarpus, and Platecarpus; the shell-crusher Carinodens; and larger mosasaurs of similar trophic levels including Tylosaurus bernardi and four other species of Prognathodon. Sea turtles such as Allopleurodon hoffmanni and Glyptochelone suickerbuycki were also prevalent in the area and other marine reptiles including indeterminate elasmosaurs have been occasionally found. Marine reptile assemblages in the New Jersey region of the province are generally equivalent with those in Europe; the mosasaur faunae are quite similar but exclude M. lemonnieri, Carinodens, Tylosaurus, and certain species of Halisaurus and Prognathodon. In addition, they exclusively feature M. conodon, Halisaurus platyspondylus and Prognathodon rapax. Many types of sharks such as Squalicorax, Cretalamna, Serratolamna, and sand sharks, as well as bony fish such as Cimolichthys, the saber-toothed herring , and the swordfish-like Protosphyraena are represented in the northern Tethyan margin.

The southern Tethyan margin was located along the equator between 20°N and 20°S, resulting in warmer tropical climates. Seabeds bordering the cratons in Africa and Arabia and extending to the Levant and Brazil provided vast shallow marine environments. These environments were dominated by mosasaurs and marine side-necked turtles. Of the mosasaurs, Globidens phosphaticus is the characteristic species of the southern province; in the African and Arabian domain, Halisaurus arambourgi and 'Platecarpus ptychodon' were also common mosasaurs alongside Globidens. Mosasaurus was not well-represented: the distribution of M. beaugei was restricted to Morocco and Brazil and isolated teeth from Syria suggested a possible presence of M. lemonnieri, although M. hoffmannii also had some presence throughout the province. Other mosasaurs from the southern Tethyan margin include the enigmatic Goronyosaurus, the shell-crushers Igdamanosaurus and Carinodens, Eremiasaurus, four other species of Prognathodon, and various other species of Halisaurus. Other marine reptiles such as the marine monitor lizard Pachyvaranus and the sea snake Palaeophis are known there. Aside from Zarafasaura in Morocco, plesiosaurs were scarce. As a tropical area, bony fish such as Enchodus and and various sharks were common throughout the southern Tethyan margin.

Many of the earliest fossils of Mosasaurus were found in Campanian stage deposits in North America, including the Western Interior Seaway, an inland sea which once flowed through what is now the central United States and Canada, and connected the Arctic Ocean to the modern-day Gulf of Mexico. The region was shallow for a seaway, reaching a maximum depth of about 800-900 meters (2,600-3,000 ft). Extensive drainage from the neighboring continents, Appalachia and Laramidia, brought in vast amounts of sediment. Together with the formation of a nutrient-rich deepwater mass from the mixing of continental freshwater, Arctic waters from the north, and warmer saline Tethyan waters from the south, this created a warm and productive seaway that supported a rich diversity of marine life.

The biogeography of the region has been subdivided into two Interior Subprovinces characterized by different climates and faunal structures, and their borders are separated in modern-day Kansas. The oceanic climate of the Northern Interior Subprovince was likely a cool temperate one, while the Southern Interior Subprovince had warm temperate to subtropical climates. The fossil assemblages throughout these regions suggest a complete faunal turnover when M. missouriensis and M. conodon appeared at 79.5 Ma, indicating that the presence of Mosasaurus in the Western Interior Seaway had a profound impact on the restructuring of marine ecosystems. The faunal structure of both provinces was generally much more diverse prior to the appearance of Mosasaurus, during a faunal stage known as the Niobraran Age, than it was during the following Navesinkan Age.

In what is now Alabama within the Southern Interior Subprovince, most of the key genera including sharks like Cretoxyrhina and the mosasaurs Clidastes, Tylosaurus, Globidens, Halisaurus, and Platecarpus disappeared and were replaced by Mosasaurus. During the Navesinkan Age, Mosasaurus dominated the whole region, accounting for around two-thirds of all mosasaur diversity with Plioplatecarpus and Prognathodon sharing the remaining third. The Northern Interior Subprovince also saw a restructuring of mosasaur assemblages, characterized by the disappearance of mosasaurs like Platecarpus and their replacement by Mosasaurus and Plioplatecarpus. Some Niobraran genera such as Tylosaurus, Cretoxyrhina, hesperornithids, and plesiosaurs including elasmosaurs such as Terminonatator and polycotylids like Dolichorhynchops maintained their presence until around the end of the Campanian, during which the entire Western Interior Seaway started receding from the north. Mosasaurus continued to be the dominant genus in the seaway until the end of the Navesinkan Age at the end of the Cretaceous. Contemporaneous fauna included sea turtles such as Protostega and ; many species of sea birds including , Ichthyornis, and Halimornis; sharks such as the mackerel sharks Cretalamna, Squalicorax, Pseudocorax, and Serratolamna, the goblin shark Scapanorhynchus, the sand tiger Odontaspis, and the sawfish-like Ischyrhiza; and bony fish such as Enchodus, Protosphyraena, Stratodus, and the ichthyodectids Xiphactinus and .

Mosasaurus is known from late Maastrichtian deposits in the Antarctic Peninsula, specifically the López de Bertodano Formation in Seymour Island. Located within the polar circle at around 65°S, temperatures at medium to large water depths would have been around 6 °C (43 °F) on average, while sea surface temperatures may have dropped below freezing and sea ice may have formed at times. Mosasaurus appears to be the most diverse mosasaur in the Maastrichtian Antarctica. At least two species of Mosasaurus have been described, but the true number of species is unknown as remains are often fragmentary and specimens are described in open nomenclature. These species include one comparable with M. lemonnieri, and another that appears to be closely related to M. hoffmannii. M. sp. has also been described. However, it is possible that such specimens may actually represent Moanasaurus, although this depends on the outcome of a pending revision of the genus. At least four other mosasaur genera have been reported in Antarctica, including Plioplatecarpus, the mosasaurines Moanasaurus and , and Kaikaifilu. The validity of some of these genera is disputed as they are primarily based on isolated teeth. Prognathodon and Globidens are also expected to be present based on distribution trends of both genera, although conclusive fossils have yet to be found. Other Antarctic marine reptiles included elasmosaurid plesiosaurs like Aristonectes and another indeterminate elasmosaurid. The fish assemblage of the López de Bertodano Formation was dominated by Enchodus and ichthyodectiformes.

Known fossils of Mosasaurus have typically been recovered from deposits representing nearshore habitats during the Cretaceous period, with some fossils coming from deeper-water deposits. Lingham-Soliar (1995) elaborated on this, finding that Maastrichtian deposits in the Netherlands with M. hoffmannii occurrences represented nearshore waters around 40-50 meters (130-160 ft) deep. Changing temperatures and an abundance in marine life were characteristic of these localities. The morphological build of M. hoffmannii, nevertheless, was best adapted for a pelagic surface lifestyle.

δ ¹³C is also correlated with a marine animal's feeding habitat as isotope levels deplete when habitat is farther from the shoreline, so some scientists interpreted isotope levels as a proxy for habitat preference. Separate studies involving multiple Mosasaurus specimens have yielded consistently low δ ¹³C levels of tooth enamel, indicating that Mosasaurus fed in more offshore or open waters. It has been pointed out how δ ¹³C can be influenced by other factors in an animal's lifestyle, such as diet and diving behavior. To account for this, a 2014 study by T. Lynn Harrell Jr. and Alberto Perez-Huerta examined the concentration ratios of neodymium, gadolinium, and ytterbium in M. hoffmannii and Mosasaurus sp. fossils from Alabama, the Demopolis Chalk, and the Hornerstown Formation. Previous studies demonstrated that ratios of these three elements can act as a proxy for relative ocean depth of a fossil during early diagenesis without interference from biological processes, with each of the three elements signifying either shallow, deep, or fresh waters. The rare earth element ratios were very consistent throughout most of the examined Mosasaurus fossils, indicating consistent habitat preference, and clustered towards a ratio representing offshore habitats with ocean depths deeper than 50 meters (160 ft).

Mosasaurus lived alongside other large predatory mosasaurs also considered apex predators, most prominent among them being the tylosaurines and Prognathodon. Tylosaurus bernardi, the only surviving species of the genus during the Maastrichtian, measured up to 12.2 meters (40 ft) in length while the largest coexisting species of Prognathodon like P. saturator exceeded 12 meters (39 ft). These three mosasaurs preyed on similar animals such as marine reptiles.

A study published in 2013 by Schulp and colleagues specifically tested how mosasaurs such as M. hoffmannii and P. saturator were able to coexist in the same localities through δ ¹³C analysis. The scientists utilized an interpretation that differences in isotope values can help explain the level of resource partitioning because it is influenced by multiple environmental factors such as lifestyle, diet, and habitat preference. Comparisons between the δ ¹³C levels in multiple teeth of M. hoffmannii and P. saturator from the Maastrichtian-age Maastricht Formation showed that while there was some convergence between certain specimens, the average δ ¹³C values between the two species were on average different. This is one indication of niche partitioning, where the two mosasaur genera likely foraged in different habitats or had different specific diets to coexist without direct competitive conflict. The teeth of P. saturator are much more robust than those of M. hoffmannii and were specifically equipped for preying on robust prey like turtles. While M. hoffmannii also preyed on turtles, its teeth were built to handle a wider range of prey less suited for P. saturator.

Another case of presumed niche partitioning between Mosasaurus and Prognathodon from the Bearpaw Formation in Alberta was documented in a 2014 study by Konishi and colleagues. The study found a dietary divide between M. missouriensis and Prognathodon overtoni based on stomach contents. Stomach contents of P. overtoni included turtles and ammonites, providing another example of a diet specialized for harder prey. In contrast, M. missouriensis had stomach contents consisting of fish, indicative of a diet specialized in softer prey. It was hypothesized that these adaptations helped maintain resource partitioning between the two mosasaurs.

Nevertheless, competitive engagement evidently could not be entirely avoided. There is also evidence of aggressive interspecific combat between Mosasaurus and other large mosasaur species. This is shown from a fossil skull of a subadult M. hoffmannii with fractures caused by a massive concentrated blow to the braincase; Lingham-Soliar (1998) argued that this blow was dealt by a ramming attack by Tylosaurus bernardi, as the formation of the fractures were characteristic of a coordinated strike (and not an accident or fossilization damage), and T. bernardi was the only known coexisting animal likely capable of causing such damage, using its robust arrow-like elongated snout. This sort of attack has been compared to the defensive behavior of bottlenose dolphins using their beaks to kill or repel lemon sharks, and it has been speculated that T. bernardi dealt the offensive attack via an ambush on an unsuspecting Mosasaurus.

By the end of the Cretaceous, mosasaurs were at the height of their evolutionary radiation, and their extinction was a sudden event. During the late Maastrichtian, global sea levels dropped, draining the continents of their nutrient-rich seaways and altering circulation and nutrient patterns, and reducing the number of available habitats for Mosasaurus. The genus adapted by accessing new habitats in more open waters. The last fossils of Mosasaurus, which include those of M. hoffmannii and indeterminate species, occur up to the Cretaceous-Paleogene boundary (K-Pg boundary). The demise of the genus was likely a result of the Cretaceous-Paleogene extinction event which also wiped out the non-avian dinosaurs. Mosasaurus fossils have been found less than 15 meters (49 ft) below the boundary in the Maastricht Formation, the Davutlar Formation in Turkey, the Jagüel Formation in Argentina, Stevns Klint in Denmark, Seymour Island, and Missouri.

M. hoffmannii fossils have been found within the K-Pg boundary itself in southeastern Missouri between the Paleocene Clayton Formation and Cretaceous Owl Creek Formation. Fossil vertebrae from the layer were found with fractures formed after death. The layer was likely deposited as a tsunamite, alternatively nicknamed the "Cretaceous cocktail deposit". This formed through a combination of catastrophic seismic and geological disturbances, mega-hurricanes, and giant tsunamis caused by the impact of the Chicxulub asteroid that catalyzed the K-Pg extinction event. As well as physical destruction, the impact also blocked out sunlight leading to a collapse of marine food webs. Any Mosasaurus surviving the immediate cataclysms by taking refuge in deeper waters would have died out due to starvation from a loss of prey.

One enigmatic occurrence of Mosasaurus sp. fossils is in the Hornerstown Formation, a deposit typically dated to be from the Paleocene Danian age, which was immediately after the Maastrichtian age. The fossils were found in association with fossils of Squalicorax, Enchodus, and various ammonites within a uniquely fossil-rich bed at the base of the Hornerstown Formation known as the Main Fossiliferous Layer. This does not mean Mosasaurus and its associated fauna survived the K-Pg extinction. According to one hypothesis, the fossils may have originated from an earlier Cretaceous deposit and were reworked into the Paleocene formation during its early deposition. Evidence of reworking typically comes from fossils worn down due to further erosion during their exposure at the time of redeposition. Many of the Mosasaurus fossils from the Main Fossiliferous Layer consist of isolated bones commonly abraded and worn, but the layer also yielded better-preserved Mosasaurus remains. Another explanation suggests the Main Fossiliferous Layer is a Maastrichtian time-averaged remanié deposit, which means it originated from a Cretaceous deposit with winnowed low-sediment conditions. A third hypothesis proposes that the layer is a lag deposit of Cretaceous sediments forced out by a strong impact by a tsunami, and what remained was subsequently refilled with Cenozoic fossils.

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Mosasaurus Reconstructed skeleton of M. hoffmannii at the Maastricht Natural History Museum Scientific classification Kingdom: Animalia Phylum: Chordata Class: Reptilia Order: Squamata Superfamily: † Mosasauroidea Family: † Mosasauridae Tribe: † Mosasaurini Genus: † Mosasaurus Conybeare, 1822 Type species † Mosasaurus hoffmannii Other species Species pending reassessment † M.

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Intercropping is the agricultural practice of cultivating two or more crops in the same space at the same time (Andrews & Kassam 1976). A practice often associated with sustainable agriculture and organic farming, it is one form of polyculture, and may benefit crop yield or the control of some kind of pest, or may have other agronomic benefits.
-Wikiopedia
The bottom line, this type of organic gardening plant integration allows for greater plant diversity for increased crop production and pest control.

Benefits of Organic Gardening Intercropping

Examples of Organic Gardening Intercopping

Vertical spacing. When you intercrop your vegetables consider the vertical spacing available in your garden. Vegetables species have different verticle requirements and can be grown on trellises. Squash, beans, cucumbers, peas, melons and tomatoes are just a few examples.

Direct Sun. During the main growing period, usually May through August the sun is at its brightest. The sun's location governs where you might locate low growing or tall growing plants. Locate tall plants on the north (south in the southern hemisphere) side of the garden. The sun will heat the south part of the garden for heat loving plants. Alternately, if you locate tall plants on the south side of the garden there will be light shade on the north side to include shade-loving plants. Shade-loving plants that can be intercropped with sun-loving plants include beans, beets, chard, leeks, lettuce, peas, radishes, and turnips.

Structure and foliage. Intercropping also involves using plants with opposite structure and foliage. Plants that have large structures or leaves, such as corn and squash, can provide a shelter and filtered sun for lower, larger leaved plants such as lettuce. Corn stalks also provide support for vegetable vines.

Timing. If you time your plantings correctly this will also help to inter-plant your vegetables. Lettuce can handle the light sun of spring and fall, but requires protection during the heat of summer. When lettuce receives too much heat they tend to bolt (go to seed). Also keep in mind the length of time it takes a vegetable species to mature; radishes for example are super fast maturing, while peppers may take the entire summer. Try to intercrop slow growing vegetables with fast growing vegetables.

Inserted vegetables. Many narrow leafed plants such as onions, leeks, shallots, and garlic can easily fit between many leafy vegetables. But, consider theplant's feeding requirements. Plants placed close together will compete for nutrients in the root zone. Select plants that have different feeding requirements.

Intercropping Combinations

I've taken the liberty of combining the intercropping with a tradition approach called companion planting for simplicity sake. I believe in keeping it simple. Companion planting in my opinion is not an exact science, but it points to some very interesting combinations and many oraganic gardeners swear by it.

The table below was compiled from traditional literature on companion planting, which to me is intercropping.

Intercropping for Pest Control

Intercropping reduces pests in a variety of ways, including:

Chemical Repellent - These plants provide odors that confuse and ward off pests. This works best in intensive intercropping.

Parasitic Wasp Host Plant - These plants provide food and shelter for parasitic wasps as they search for pests.

Parasitic Wasp Increase - Intercropping plants attract parasitic wasps as a food source from either the plant or the pests.

Physical Interference - These plants "get in the way" of the pest as either a physical barrier or life cycle interference.

Predator Increase - These plants act as a food source or breeding ground for beneficial insects as they search out for pests.

Trap Crop - Another form of Intercropping is Trap cropping. Trap cropping encourages pests to congregate, which makes it easier for beneficial insects to prey and for handpicking.

Visual Masking - These plants provide a visual mask that confuses the pest or concealed the main crop.

Pest Control Intercropping Matrix

Retun to the top of Intercropping

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Intercropping allows for greater plant diversity, which reduces pests

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Intercropping is a time-honored agricultural technique. While previously it was applied with no specific knowledge, present-day farmers can reap good harvests both with advanced machinery, scientific background of intercropping benefits, and precision agriculture tools. Reasons for intercropping include saving space and resources, ensuring better yields in case of poor returns of the main culture, repelling pests, reducing weeds, proving nutrients for the neighboring plants, among others. Considering intercropping pros and cons, many landowners opt for the method even though it involves additional field treatment. Nonetheless, wise matches in intercropping combinations bring positive results.

What Is Intercropping In Agriculture?

The intercropping system employs growing several species in-between each other during the same season, alternatively to monoculture farming. Intercropping practices differ in the arrangement, sowing time, and plant combinations. Thus, perennials can grow together with other perennials or annuals, and annuals can grow with other annuals. An example of a perennial-annual intercropping match is garlic and tomatoes. In tropical regions, coffee and banana make a popular perennial combination.

Regarding the time of seeding, plants are sown either at the same time or when other species are already flowering or ready for harvesting.

Types Of Intercropping

While planting different species together, farmers should consider their density, architecture, required period for maturing, irrigation, sunlight, and nutrient needs. Intercropping involves a certain arrangement of plants that gives the basis for its classification. Thus, intercropping types fall into the row, strip, relay, temporal, mixed, guard, alley, trap, repellant, and push-pull cropping among others.

Row Cropping

As the name suggests, plants are arranged in rows in this case. A common and beneficial combination is cereals with legumes like corn and beans. Row ratios may vary, including either single or multiple rows. A study recommends four maize rows with six soybean ones. The benefits of row cropping here include additional nitrogen fixation by legumes in symbiosis with the bacteria of the Rhizobium genus.

Strip Intercropping

What does it imply and what is the purpose of strip cropping? The practice is similar to row cropping, but the sections of land are wide enough to facilitate machine operations and to enable independent cultivations. A popular pattern of strip cropping in the U.S. is growing wheat, corn, and soybeans alternatively, six rows each.

Alley Cropping

The alley cropping system suggests growing crops in-between trees, bushes, or hedges forming alleys. The aspects of alley cropping are as follows. Higher plants protect the lower ones from winds and shelter from extra sunlight as well as prevent soil erosion with their vigorous root systems.

Relay Cropping

Farmers practicing this technique plant one or two more species at the same piece of land but at different times, after one crop has flowered. Relay intercropping reduces temporal overlap in harvesting different species, but the second crop must be tolerant of the shade of the first one. Examples of the relay cropping system are cotton and corn or chickpea and upland rice.

Temporal Intercropping

In this intercropping method, combined plants require different maturing time. When the fast-growing plant is harvested, the slow-growing one has more space to develop.

Mixed Intercropping

The intercropping practice involves sowing different species (two or more) in one terrain with no distinct arrangement in rows or in the same rows. In this case, the time to sow and harvest coincides. Mixed cropping gives additional protection to the primary culture from winds, frosts, droughts, and other severe weather conditions.

Trap Cropping

As the name hints, the intercropping technique aids in trapping pests to protect the main culture. Popular examples of trapping plants are mustard, marigold, among others. The basic idea is to attract insects or fungi to the sacrificial secondary crops, thus protecting the cash one. Blue Hubbard squash is reported to be an efficient remedy from squash bugs, squash vine borers, spotted and striped cucumber beetles.

Trap intercropping allows saving on pesticides with no chemical application at all or partial treatment of trapping areas. However, possible disadvantages of intercropping, in this case, include developing resistance to insecticides or uncontrolled pest nurseries.

EOS Crop Monitoring

Using satellite monitoring for remote fields management in one platform!

Guard Cropping

Guard crops are thorny or hardy plants growing around the cash crops or along the field edges. Crop guards are used as barriers to protect the main species from winds or invasions. For this reason, sorghum is grown around cotton or safflower around chickpea.

Repellant Intercropping

While applying this intercropping method, farmers utilize pest-repellant plants as a sustainable pest-management technique. It relies on the repellant effect of certain species, thus protecting the cash crop. The repellant deters insects from their host plant like in the case of planting leeks to protect beans from bean flies.

Push-Pull Cropping

The intercropping practice combines both trap and repellent plants for the sake of the cash crop. While trap species attract (or pull) pests, repellant ones push them away. A pattern to illustrate this technique is growing Napier grass (to pull) and Desmodium legume (to push) in order to protect corn from stem boring corn larvae.

Benefits Of Intercropping

Intercropping has significant advantages over monoculture farming, which are aimed at boosting yields and more efficient usage of land and resources. The most fundamental intercropping benefits include the following:

Increased profit. Secondary crops provide more returns and ensure profit even when the primary crop fails.

Ergonomic usage of land. Planting species in-between rows allows utilizing the soil in a more efficient way, unlike monocropping when spaces between rows are unused.

Protection of the cash crop. Intercropping performs several functions, either repelling or trapping pests and attracting beneficial ones as well as protecting from winds or giving shelter from extra sunlight. Pest management reduces chemical applications and thus saves costs.

Prevention of soil erosion and crust. Plants between rows and in alley intercropping, in particular, mitigate erosion with their roots.

Added nutrients for the main crop. The leguminous family is known for nitrogen fixation and thus provides nitrogen for the neighboring species.

Reduction of fertilizer applications. When intercropping cultures contribute to soil fertility, they spare the necessity to apply synthesized fertilizers.

More efficient use of natural resources like water and solar energy as they are distributed to secondary crops as well.

Improved weed management. Beneficial plants, not weeds, occupy vacant spaces between rows in intercropping.

Enhanced biodiversity and ecological stability. The more agricultural species grow, the better it is for the environment.

Rules To Follow In Intercropping

The basic idea in proper companion matches is to make them benefit from each other, not compete. The intercropping practice is based on principles and rules with respect to different plant families, architecture, time of maturing, growth habits (sunlight and water needs in particular):

Combine high growing and wide growing species.

Match shallow-rooted plants with deep-rooted ones.

Select species with similar water needs (e.g. cabbage demanding abundant irrigation must not grow together with companions requiring scarce water supply).

Match plants that do not compete for sunlight (one should be able to develop in the shade of the other).

Avoid grouping crops of the same family to mitigate pest invasions. For this reason, you must not plant potatoes with eggplants or tomatoes; however, they go well with beetroots. On the contrary, combinations of different families in intercropping eliminate infestation. Thus, matches of solanaceous plants with corn reduce the movement of Colorado potato beetles (host vs. non-host crops).

Mind possible disease outbreaks due to close interaction in intercropping. Note that pests not only damage crops physically by eating but bear viruses critical for specific vegetation.

Add culinary herbs for the repellant effect.

Plant legumes with non-legumes to improve soil fertility (to raise the concentration of nitrogen).

Sow attractant intercropping species to lure pollinators.

Choose slow-growing and fast-growing cultures. In this case, when the latter are harvested, the first ones will have enough space to develop.

Consider allelopathic properties, which are among the main disadvantages of intercropping.

Select plants for physical support. Beans greatly wine on corn. However, their immediate neighborhood complicates field operations.

Intercropping With EOS Crop Monitoring

The benefits of intercropping don't come for free though. Competition, allelopathy, and pest control are some of the major issues to address. Plant interaction demands particular control, which is a time-consuming process and a difficult task for a human eye. In this regard, satellite-based EOS Crop Monitoring software provides precious information on the overall crop health in the field.

Vegetation indices aid in monitoring growth stages and detecting anomalies since each particular crop has specific values at a certain phenological stage. This correlation allows farmers to make weighted agricultural decisions. Thus, the sunflower is supposed to give a high NDVI index while flowering. Correspondingly, if it is low, it means that things go wrong, and the area should be checked.

Even in this case, there is no need for farmers to do it physically as they can assign the task to the scouting app from the comfort of their offices. After viewing the problem closer remotely, agriculturalists inspect the area in person for details and proper reaction.

Currently, the platform assists the USA farmers in monitoring growth stages of spring barley, maize, cotton, soybean, winter wheat, pulses, rice, and sunflower. For Custom Projects to monitor crops that are not on the list, please contact the EOS Crop Monitoring sales team at sales@eos.com.

Running a farming business with EOS Crop Monitoring is simpler, and the possibilities of the online software are not limited by the features mentioned.

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Intercropping Concept & Types: How To Benefit From The Practice

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Intercropping is a time-honored agricultural technique. While previously it was applied with no specific knowledge, present-day farmers can reap good harvests both with advanced machinery, scientific background of intercropping benefits, and precision agriculture tools. Reasons for intercropping include saving space and resources, ensuring better yields in case of poor returns of the main culture, repelling pests, reducing weeds, proving nutrients for the neighboring plants, among others.

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Intercropping is a multiple cropping practice that involves growing two or more crops in proximity. In other words, intercropping is the cultivation of two or more crops simultaneously on the same field. The most common goal of intercropping is to produce a greater yield on a given piece of land by making use of resources or ecological processes that would otherwise not be utilized by a single crop.[citation needed ]

The degree of spatial and temporal overlap in the two crops can vary somewhat, but both requirements must be met for a cropping system to be an intercrop. Numerous types of intercropping, all of which vary the temporal and spatial mixture to some degree, have been identified. These are some of the more significant types:

Mixed intercropping, as the name implies, is the most basic form in which the component crops are totally mixed in the available space.

Row cropping involves the component crops arranged in alternate rows. Variations include alley cropping, where crops are grown in between rows of trees, and strip cropping, where multiple rows, or a strip, of one crop are alternated with multiple rows of another crop. A new version of this is to intercrop rows of solar photovoltaic modules with agriculture crops. This practice is called agrivoltaics.

Temporal intercropping uses the practice of sowing a fast-growing crop with a slow-growing crop, so that the fast-growing crop is harvested before the slow-growing crop starts to mature.

Further temporal separation is found in relay cropping, where the second crop is sown during the growth, often near the onset of reproductive development or fruiting, of the first crop, so that the first crop is harvested to make room for the full development of the second.

Crop rotation is related, but is not intercropping, as the different types of crops are grown in a sequence of growing seasons rather than in a single season.

Resource partitioning

Careful planning is required, taking into account the soil, climate, crops, and varieties. It is particularly important not to have crops competing with each other for physical space, nutrients, water, or sunlight. Examples of intercropping strategies are planting a deep- rooted crop with a shallow-rooted crop, or planting a tall crop with a shorter crop that requires partial shade. Inga alley cropping has been proposed as an alternative to the ecological destruction of slash-and-burn farming.

When crops are carefully selected, other agronomic benefits are also achieved.

Planting two crops in close proximity can especially be beneficial when the two plants interact in a way that increases one or both of the plant's fitness (and therefore yield). For example, plants that are prone to tip over in wind or heavy rain (lodging-prone plants), may be given structural support by their companion crop. Climbing plants such as black pepper can also benefit from structural support. Some plants are used to suppress weeds or provide nutrients. Delicate or light-sensitive plants may be given shade or protection, or otherwise wasted space can be utilized. An example is the tropical multi-tier system where coconut occupies the upper tier, banana the middle tier, and pineapple, ginger, or leguminous fodder, medicinal or aromatic plants occupy the lowest tier.

Intercropping of compatible plants can also encourage biodiversity, by providing a habitat for a variety of insects and soil organisms that would not be present in a single-crop environment. These organisms may provide crops valuable nutrients, such as through nitrogen fixation.

Pest management

There are several ways in which increasing crop diversity may help improve pest management. For example, such practices may limit outbreaks of crop pests by increasing predator biodiversity. Additionally, reducing the homogeneity of the crop can potentially increase the barriers against biological dispersal of pest organisms through the crop.

There are several ways pests can be controlled through intercropping:

Trap cropping, this involves planting a crop nearby that is more attractive for pests compared to the production crop, the pests will target this crop and not the production crop.

Repellant intercrops, an intercrop that has a repellent effect to certain pests can be used. This system involved the repellant crop masking the smell of the production crop in order to keep pests away from it.

Push-pull cropping, this is a mixture of trap cropping and repellant intercropping. An attractant crop attracts the pest and a repellant crop is also used to repel the pest away.

Limitations

Intercropping to reduce pest damage in agriculture, has been deployed with varying success. For example, while trap cropping has reduced pest densities at a commercial in experiments, it often fails to decrease pest densities deployed in large scale commercial landscapes. Furthermore, increasing crop diversity through intercropping does not necessarily increase the presence of the predators of crop pests. In a systematic review of the literature, in 2008, in the studies examined, predators of pests tended only increased under crop diversification strategies in 53 percent of studies, and crop diversification only led to increased yield in only 32% of the studies.

1. Andrews, D.J., A.H. Kassam. 1976. The importance of multiple cropping in increasing world food supplies. pp. 1-10 in R.I. Papendick, A. Sanchez, G.B. Triplett (Eds.), ^ Multiple Cropping. ASA Special Publication 27. American Society of Agronomy, Madison, WI.

2. ^ Lithourgidis, A.S.; Dordas, C.A.; Damalas, C.A.; Vlachostergios, D.N. (2011). "Annual intercrops: an alternative pathway for sustainable agriculture" (PDF). Australian Journal of Crop Science. 5 (4): 396-410.

3. ^ Dinesh, Harshavardhan; Pearce, Joshua M. (2016-02-01). "The potential of agrivoltaic systems". Renewable and Sustainable Energy Reviews. 54: 299-308. doi:10.1016/j.rser.2015.10.024.

4. Elkan, Daniel. ^ Slash-and-burn farming has become a major threat to the world's rainforest The Guardian 21 April 2004

5. Trenbath, B.R. 1976. Plant interactions in mixed cropping communities. pp. 129-169 in R.I. Papendick, A. Sanchez, G.B. Triplett (Eds.), ^ Multiple Cropping. ASA Special Publication 27. American Society of Agronomy, Madison, WI.

6. ^ Mt. Pleasant, Jane (2006). "The science behind the Three Sisters mound system: An agronomic assessment of an indigenous agricultural system in the northeast". In John E. Staller; Robert H. Tykot; Bruce F. Benz (eds.). Histories of maize: Multidisciplinary approaches to the prehistory, linguistics, biogeography, domestication, and evolution of maize. Amsterdam. pp. 529-537.

7. ^ Miguel Angel Altieri; Clara Ines Nicholls (2004). Biodiversity and Pest Management in Agroecosystems, Second Edition. Psychology Press. ISBN 9781560229230.

8. ^ "Controlling Pests with Plants: The power of intercropping - UVM Food Feed". UVM Food Feed. 2014-01-09.

9. ^ Holden, Matthew H.; Ellner, Stephen P.; Lee, Doo-Hyung; Nyrop, Jan P.; Sanderson, John P. (2012-06-01). "Designing an effective trap cropping strategy: the effects of attraction, retention and plant spatial distribution". Journal of Applied Ecology. 49 (3): 715-722. doi:10.1111/j.1365-2664.2012.02137.x.

10. ^ Poveda, Katja; Gómez, María Isabel; Martínez, Eliana (2008-12-01). "Diversification practices: their effect on pest regulation and production". Revista Colombiana de Entomología. 34 (2): 131-144.

11. ^ Improving nutrition through home gardening, Home Garden Technology Leaflet 13: Multilayer cropping, FAO, 2001

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Intercropping is a multiple cropping practice that involves growing two or more crops in proximity. In other words, intercropping is the cultivation of two or more crops simultaneously on the same field.

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Ethan, Jason, Lewis Central Idea Development

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Ethan, Jason, Lewis Central Idea Development

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Option 1:

"The establishment and implementation of animal rights reflect societal values and influence species protection."

Primary Concepts: Function, Form, Responsibility

This version emphasizes the purpose and structure of animal rights systems

Lines of Inquiry could explore:

The nature of animal rights and protection laws

Implementation of animal welfare measures

Impact of protection systems on animal wellbeing

Option 2:

"Human actions and attitudes towards animals determine their treatment and survival."

Primary Concepts: Causation, Function, Responsibility

This version focuses on the relationship between human behavior and animal welfare

Lines of Inquiry could explore:

Factors influencing animal treatment

Effects of human actions on animal populations

Ways to promote animal protection

Option 3:

"The development of animal protection systems reflects changing societal understanding of animal welfare."

Primary Concepts: Form, Change, Function

This version combines your stronger concepts with evolution of protection systems

Lines of Inquiry could explore:

Structure of animal protection systems

Evolution of animal rights over time

Role of advocacy in animal protection

Key Conceptual Understandings these support:

Animal rights are structured systems that serve specific purposes

Human actions directly impact animal welfare

Protection systems evolve with societal understanding

Different perspectives influence animal treatment

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Let me analyze these lines of inquiry to generate a meaningful central idea about monocropping.

Analysis of Lines of Inquiry:

1. "What is monocropping" → explores systems, practices, and agricultural methods

2. "What is the impact of monocropping" → examines consequences, relationships, and sustainability

3. "What can be done to stop the negative effects of monocropping" → investigates solutions, responsibility, and change

Key Concepts emerging from these lines:

- Systems

- Impact

- Sustainability

- Change

- Responsibility

- Causation

- Connection

Conceptual Relationships:

- Agricultural practices impact environmental systems

- Human choices affect ecological balance

- Sustainable solutions require understanding of systems

- Actions and consequences are interconnected

Based on this analysis, here are some possible central ideas (from broad to more specific):

1. "Agricultural practices like monocropping reflect human choices that impact environmental sustainability and require systematic solutions."

2. "The relationship between farming methods and environmental sustainability reveals the need for responsible agricultural practices."

3. "Modern agricultural systems can create environmental challenges that require innovative and sustainable solutions."

I recommend the first option because it:

- Addresses all three lines of inquiry comprehensively

- Incorporates key concepts (systems, impact, sustainability)

- Makes clear connections between choices and consequences

- Promotes critical thinking about agricultural practices

- Enables investigation of both problems and solutions

- Encourages consideration of alternative practices

- Opens discussion about responsibility and change

This central idea can be supported by these conceptual understandings:

1. Agricultural practices influence ecological systems in multiple ways

2. Short-term economic benefits may lead to long-term environmental consequences

3. Sustainable agriculture requires balance between productivity and environmental protection

4. Individual and collective choices in farming practices affect global sustainability

To support investigation of this central idea, consider these aspects:

- Environmental impacts

- Economic factors

- Social implications

- Alternative farming methods

- Global food security

- Biodiversity

- Soil health

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Tyrannosaurus is a genus of large theropod dinosaur. The species Tyrannosaurus rex ( rex meaning "king" in Latin), often called T. rex or colloquially T-Rex, is one of the best represented theropods. It lived throughout what is now western North America, on what was then an island continent known as Laramidia. Tyrannosaurus had a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the Upper Cretaceous period, 68 to 66 million years ago. It was the last known member of the tyrannosaurids and among the last non- avian dinosaurs to exist before the Cretaceous-Paleogene extinction event.

Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, the forelimbs of Tyrannosaurus were short but unusually powerful for their size, and they had two clawed digits. The most complete specimen measures up to 12.3-12.4 m (40-41 ft) in length, but according to most modern estimates, Tyrannosaurus could have exceeded sizes of 13 m (43 ft) in length, 3.7-4 m (12-13 ft) in hip height, and 8 tonnes (7.9 long tons; 8.8 short tons) in mass. Although many other theropods likely rivaled Tyrannosaurus in size, it is still among the largest known land predators and is estimated to have exerted the strongest bite force among all terrestrial animals. By far the largest carnivore in its environment, Tyrannosaurus rex was most likely an apex predator, preying upon hadrosaurs, juvenile armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. Some experts have suggested the dinosaur was primarily a scavenger. The question of whether Tyrannosaurus was an apex predator or a pure scavenger was among the longest debates in paleontology. Most paleontologists today accept that Tyrannosaurus was both an active predator and a scavenger.

Specimens of Tyrannosaurus rex include some that are nearly complete skeletons. Soft tissue and proteins have been reported in at least one of these specimens. The abundance of fossil material has allowed significant research into many aspects of its biology, including its life history and biomechanics. The feeding habits, physiology, and potential speed of Tyrannosaurus rex are a few subjects of debate. Its taxonomy is also controversial, as some scientists consider Tarbosaurus bataar from Asia to be a second Tyrannosaurus species, while others maintain Tarbosaurus is a separate genus. Several other genera of North American tyrannosaurids have also been synonymized with Tyrannosaurus.

As the archetypal theropod, Tyrannosaurus has been one of the best-known dinosaurs since the early 20th century and has been featured in film, advertising, postal stamps, and many other media.

History of research

Earliest finds

Type specimen (AMNH 3982) of Manospondylus gigas

Teeth from what is now documented as a Tyrannosaurus rex were found in 1874 by Arthur Lakes near Golden, Colorado. In the early 1890s, John Bell Hatcher collected postcranial elements in eastern Wyoming. The fossils were believed to be from the large species Ornithomimus grandis (now ) but are now considered T. rex remains.

In 1892, Edward Drinker Cope found two vertebral fragments of a large dinosaur. Cope believed the fragments belonged to an "agathaumid" ( ceratopsid) dinosaur, and named them Manospondylus gigas, meaning "giant porous vertebra", in reference to the numerous openings for blood vessels he found in the bone. The M. gigas remains were, in 1907, identified by Hatcher as those of a theropod rather than a ceratopsid.

Henry Fairfield Osborn recognized the similarity between Manospondylus gigas and T. rex as early as 1917, by which time the second vertebra had been lost. Owing to the fragmentary nature of the Manospondylus vertebrae, Osborn did not synonymize the two genera, instead considering the older genus indeterminate. In June 2000, the Black Hills Institute found around 10% of a Tyrannosaurus skeleton ( BHI 6248) at a site that might have been the original M. gigas locality.

Skeleton discovery and naming

Barnum Brown, assistant curator of the American Museum of Natural History, found the first partial skeleton of T. rex in eastern Wyoming in 1900. Brown found another partial skeleton in the Hell Creek Formation in Montana in 1902, comprising approximately 34 fossilized bones. Writing at the time Brown said "Quarry No. 1 contains the femur, pubes, humerus, three vertebrae and two undetermined bones of a large Carnivorous Dinosaur not described by Marsh. ... I have never seen anything like it from the Cretaceous." Henry Fairfield Osborn, president of the American Museum of Natural History, named the second skeleton T. rex in 1905. The generic name is derived from the Greek words ( tyrannos, meaning "tyrant") and ( sauros, meaning "lizard"). Osborn used the Latin word rex, meaning "king", for the specific name. The full binomial therefore translates to "tyrant lizard the king" or "King Tyrant Lizard", emphasizing the animal's size and presumed dominance over other species of the time.

Dynamosaurus imperiosus holotype, Natural History Museum

Osborn named the other specimen Dynamosaurus imperiosus in a paper in 1905. In 1906, Osborn recognized that the two skeletons were from the same species and selected Tyrannosaurus as the preferred name. The original Dynamosaurus material resides in the collections of the Natural History Museum, London. In 1941, the T. rex type specimen was sold to the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, for $7,000. Dynamosaurus would later be honored by the 2018 description of another species of tyrannosaurid by Andrew McDonald and colleagues, Dynamoterror dynastes, whose name was chosen in reference to the 1905 name, as it had been a "childhood favorite" of McDonald's.

From the 1910s through the end of the 1950s, Barnum's discoveries remained the only specimens of Tyrannosaurus, as the Great Depression and wars kept many paleontologists out of the field.

Resurgent interest

Specimen "Sue", Field Museum of Natural History, Chicago

Beginning in the 1960s, there was renewed interest in Tyrannosaurus, resulting in the recovery of 42 skeletons (5-80% complete by bone count) from Western North America. In 1967, Dr. William MacMannis located and recovered the skeleton named "MOR 008", which is 15% complete by bone count and has a reconstructed skull displayed at the Museum of the Rockies. The 1990s saw numerous discoveries, with nearly twice as many finds as in all previous years, including two of the most complete skeletons found to date: Sue and Stan.

Sue Hendrickson, an amateur paleontologist, discovered the most complete (approximately 85%) and largest Tyrannosaurus skeleton in the Hell Creek Formation on August 12, 1990. The specimen Sue, named after the discoverer, was the object of a legal battle over its ownership. In 1997, the litigation was settled in favor of Maurice Williams, the original land owner. The fossil collection was purchased by the Field Museum of Natural History at auction for $7.6 million, making it the most expensive dinosaur skeleton until the sale of Stan for $31.8 million in 2020. From 1998 to 1999, Field Museum of Natural History staff spent over 25,000 hours taking the rock off the bones. The bones were then shipped to New Jersey where the mount was constructed, then shipped back to Chicago for the final assembly. The mounted skeleton opened to the public on May 17, 2000, in the Field Museum of Natural History. A study of this specimen's fossilized bones showed that Sue reached full size at age 19 and died at the age of 28, the longest estimated life of any tyrannosaur known.

Another Tyrannosaurus, nicknamed Stan (BHI 3033), in honor of amateur paleontologist Stan Sacrison, was recovered from the Hell Creek Formation in 1992. Stan is the second most complete skeleton found, with 199 bones recovered representing 70% of the total. This tyrannosaur also had many bone pathologies, including broken and healed ribs, a broken (and healed) neck, and a substantial hole in the back of its head, about the size of a Tyrannosaurus tooth.

In 1998, Bucky Derflinger noticed a T. rex toe exposed above ground, making Derflinger, who was 20 years old at the time, the youngest person to discover a Tyrannosaurus. The specimen, dubbed Bucky in honor of its discoverer, was a young adult, 3.0 metres (10 ft) tall and 11 metres (35 ft) long. Bucky is the first Tyrannosaurus to be found that preserved a furcula (wishbone). Bucky is permanently displayed at The Children's Museum of Indianapolis.

In the summer of 2000, crews organized by Jack Horner discovered five Tyrannosaurus skeletons near the Fort Peck Reservoir. In 2001, a 50% complete skeleton of a juvenile Tyrannosaurus was discovered in the Hell Creek Formation by a crew from the Burpee Museum of Natural History. Dubbed Jane (BMRP 2002.4.1), the find was thought to be the first known skeleton of a pygmy tyrannosaurid, Nanotyrannus, but subsequent research revealed that it is more likely a juvenile Tyrannosaurus, and the most complete juvenile example known; Jane is exhibited at the Burpee Museum of Natural History. In 2002, a skeleton named Wyrex, discovered by amateur collectors Dan Wells and Don Wyrick, had 114 bones and was 38% complete. The dig was concluded over 3 weeks in 2004 by the Black Hills Institute with the first live online Tyrannosaurus excavation providing daily reports, photos, and video.

In 2006, Montana State University revealed that it possessed the largest Tyrannosaurus skull yet discovered (from a specimen named MOR 008), measuring 5 feet (152 cm) long. Subsequent comparisons indicated that the longest head was 136.5 centimetres (53.7 in) (from specimen LACM 23844) and the widest head was 90.2 centimetres (35.5 in) (from Sue).

Two isolated fossilized footprints have been tentatively assigned to T. rex. The first was discovered at Philmont Scout Ranch, New Mexico, in 1983 by American geologist Charles Pillmore. Originally thought to belong to a hadrosaurid, examination of the footprint revealed a large 'heel' unknown in ornithopod dinosaur tracks, and traces of what may have been a hallux, the dewclaw-like fourth digit of the tyrannosaur foot. The footprint was published as the ichnogenus Tyrannosauripus pillmorei in 1994, by Martin Lockley and Adrian Hunt. Lockley and Hunt suggested that it was very likely the track was made by a T. rex, which would make it the first known footprint from this species. The track was made in what was once a vegetated wetland mudflat. It measures 83 centimeters (33 in) long by 71 centimeters (28 in) wide.

A second footprint that may have been made by a Tyrannosaurus was first reported in 2007 by British paleontologist Phil Manning, from the Hell Creek Formation of Montana. This second track measures 72 centimeters (28 in) long, shorter than the track described by Lockley and Hunt. Whether or not the track was made by Tyrannosaurus is unclear, though Tyrannosaurus is the only large theropod known to have existed in the Hell Creek Formation.

A set of footprints in Glenrock, Wyoming dating to the Maastrichtian stage of the Late Cretaceous and hailing from the Lance Formation were described by Scott Persons, Phil Currie and colleagues in 2016, and are believed to belong to either a juvenile T. rex or the dubious tyrannosaurid Nanotyrannus lancensis. From measurements and based on the positions of the footprints, the animal was believed to be traveling at a walking speed of around 2.8 to 5 miles per hour and was estimated to have a hip height of 1.56 m (5.1 ft) to 2.06 m (6.8 ft). A follow-up paper appeared in 2017, increasing the speed estimations by 50-80%.

Description

T. rex was one of the largest land carnivores of all time. One of the largest and the most complete specimens, nicknamed Sue (FMNH PR2081), is located at the Field Museum of Natural History in Chicago. Sue measured 12.3-12.4 m (40.4-40.7 ft) long, was 3.66-3.96 meters (12-13 ft) tall at the hips, and according to the most recent studies, using a variety of techniques, maximum body masses have been estimated approximately 8.4-8.46 metric tons (9.26-9.33 short tons). A specimen nicknamed Scotty (RSM P2523.8), located at the Royal Saskatchewan Museum, is reported to measure 13 m (43 ft) in length. Using a mass estimation technique that extrapolates from the circumference of the femur, Scotty was estimated as the largest known specimen at 8.87 metric tons (9.78 short tons) in body mass.

Not every adult Tyrannosaurus specimen recovered is as big. Historically average adult mass estimates have varied widely over the years, from as low as 4.5 metric tons (5.0 short tons), to more than 7.2 metric tons (7.9 short tons), with most modern estimates ranging between 5.4 metric tons (6.0 short tons) and 8.0 metric tons (8.8 short tons).

The largest known T. rex skulls measure up to 1.54 meters (5 ft) in length. Large fenestrae (openings) in the skull reduced weight, as in all carnivorous theropods. In other respects Tyrannosaurus's skull was significantly different from those of large non- tyrannosaurid theropods. It was extremely wide at the rear but had a narrow snout, allowing unusually good binocular vision. The skull bones were massive and the nasals and some other bones were fused, preventing movement between them; but many were pneumatized (contained a "honeycomb" of tiny air spaces) and thus lighter. These and other skull-strengthening features are part of the tyrannosaurid trend towards an increasingly powerful bite, which easily surpassed that of all non-tyrannosaurids. The tip of the upper jaw was U-shaped (most non-tyrannosauroid carnivores had V-shaped upper jaws), which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it also increased the stresses on the front teeth.

The teeth of T. rex displayed marked heterodonty (differences in shape). The premaxillary teeth, four per side at the front of the upper jaw, were closely packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards. The D-shaped cross-section, reinforcing ridges and backwards curve reduced the risk that the teeth would snap when Tyrannosaurus bit and pulled. The remaining teeth were robust, like "lethal bananas" rather than daggers, more widely spaced and also had reinforcing ridges. Those in the upper jaw, twelve per side in mature individuals, were larger than their counterparts of the lower jaw, except at the rear. The largest found so far is estimated to have been 30.5 centimeters (12 in) long including the root when the animal was alive, making it the largest tooth of any carnivorous dinosaur yet found. The lower jaw was robust. Its front dentary bone bore thirteen teeth. Behind the tooth row, the lower jaw became notably taller. The upper and lower jaws of Tyrannosaurus, like those of many dinosaurs, possessed numerous foramina, or small holes in the bone. Various functions have been proposed for these foramina, such as a crocodile-like sensory system or evidence of extra-oral structures such as scales or potentially lips, with subsequent research on theropod tooth wear patterns supporting such a proposition.

The vertebral column of Tyrannosaurus consisted of ten neck vertebrae, thirteen back vertebrae and five sacral vertebrae. The number of tail vertebrae is unknown and could well have varied between individuals but probably numbered at least forty. Sue was mounted with forty-seven of such caudal vertebrae. The neck of T. rex formed a natural S-shaped curve like that of other theropods. Compared to these, it was exceptionally short, deep and muscular to support the massive head. The second vertebra, the axis, was especially short. The remaining neck vertebrae were weakly opisthocoelous, i.e. with a convex front of the vertebral body and a concave rear. The vertebral bodies had single pleurocoels, pneumatic depressions created by air sacs, on their sides. The vertebral bodies of the torso were robust but with a narrow waist. Their undersides were keeled. The front sides were concave with a deep vertical trough. They had large pleurocoels. Their neural spines had very rough front and rear sides for the attachment of strong tendons. The sacral vertebrae were fused to each other, both in their vertebral bodies and neural spines. They were pneumatized. They were connected to the pelvis by transverse processes and sacral ribs. The tail was heavy and moderately long, in order to balance the massive head and torso and to provide space for massive locomotor muscles that attached to the thighbones. The thirteenth tail vertebra formed the transition point between the deep tail base and the middle tail that was stiffened by a rather long front articulation processes. The underside of the trunk was covered by eighteen or nineteen pairs of segmented belly ribs.

The shoulder girdle was longer than the entire forelimb. The shoulder blade had a narrow shaft but was exceptionally expanded at its upper end. It connected via a long forward protrusion to the coracoid, which was rounded. Both shoulder blades were connected by a small furcula. The paired breast bones possibly were made of cartilage only.

The forelimb or arm was very short. The upper arm bone, the humerus, was short but robust. It had a narrow upper end with an exceptionally rounded head. The lower arm bones, the ulna and radius, were straight elements, much shorter than the humerus. The second metacarpal was longer and wider than the first, whereas normally in theropods the opposite is true. The forelimbs had only two clawed fingers, along with an additional splint-like small third metacarpal representing the remnant of a third digit.

The pelvis was a large structure. Its upper bone, the ilium, was both very long and high, providing an extensive attachment area for hindlimb muscles. The front pubic bone ended in an enormous pubic boot, longer than the entire shaft of the element. The rear ischium was slender and straight, pointing obliquely to behind and below.

In contrast to the arms, the hindlimbs were among the longest in proportion to body size of any theropod. In the foot, the metatarsus was "arctometatarsalian", meaning that the part of the third metatarsal near the ankle was pinched. The third metatarsal was also exceptionally sinuous. Compensating for the immense bulk of the animal, many bones throughout the skeleton were hollowed, reducing its weight without significant loss of strength.

Classification

Skull casts of different Tyrannosaurus specimens

Tyrannosaurus is the type genus of the superfamily Tyrannosauroidea, the family Tyrannosauridae, and the subfamily Tyrannosaurinae; in other words it is the standard by which paleontologists decide whether to include other species in the same group. Other members of the tyrannosaurine subfamily include the North American Daspletosaurus and the Asian Tarbosaurus, both of which have occasionally been synonymized with Tyrannosaurus. Tyrannosaurids were once commonly thought to be descendants of earlier large theropods such as megalosaurs and carnosaurs, although more recently they were reclassified with the generally smaller coelurosaurs.

Many phylogenetic analyses have found Tarbosaurus bataar to be the sister taxon of T. rex. The discovery of the tyrannosaurid further indicates that Tarbosaurus and Tyrannosaurus are closely related, forming a clade with fellow Asian tyrannosaurid Zhuchengtyrannus, with Lythronax being their sister taxon. A further study from 2016 by Steve Brusatte, Thomas Carr and colleagues, also indicates that Tyrannosaurus may have been an immigrant from Asia, as well as a possible descendant of Tarbosaurus.

Below is the cladogram of Tyrannosauridae based on the phylogenetic analysis conducted by Loewen and colleagues in 2013.

Additional species

Diagram showing the differences between a generalized Tarbosaurus (A) and Tyrannosaurus (B) skull

In 1955, Soviet paleontologist Evgeny Maleev named a new species, Tyrannosaurus bataar, from Mongolia. By 1965, this species was renamed as a distinct genus, Tarbosaurus bataar. While most palaeontologists continue to maintain the two as distinct genera, some authors such as Thomas Holtz, Kenneth Carpenter, and Thomas Carr argue that the two species are similar enough to be considered members of the same genus, with the Mongolian taxon having the resulting binomial of Tyrannosaurus bataar.

In 2001, various tyrannosaurid teeth and a metatarsal unearthed in a quarry near Zhucheng, China were assigned by Chinese paleontologist Hu Chengzhi to the newly erected species Tyrannosaurus zhuchengensis. However, in a nearby site, a right maxilla and left jawbone were assigned to the newly erected tyrannosaurid genus Zhuchengtyrannus in 2011. It is possible that T. zhuchengensis is synonymous with Zhuchengtyrannus. In any case, T. zhuchengensis is considered to be a nomen dubium as the holotype lacks diagnostic features below the level Tyrannosaurinae.

In a 2022 study, Gregory S. Paul and colleagues argued that Tyrannosaurus rex, as traditionally understood, actually represents three species: the type species Tyrannosaurus rex, and two new species: T. imperator (meaning "tyrant lizard emperor") and T. regina (meaning "tyrant lizard queen"). The holotype of the former ( T. imperator) is the Sue specimen, and the holotype of the latter ( T. regina) is Wankel rex. The division into multiple species was primarily based on the observation of a very high degree of variation in the proportions and robusticity of the femur (and other skeletal elements) across catalogued T. rex specimens, more so than that observed in other theropods recognized as one species. Differences of general body proportions representing robust and gracile morphotypes were also used as a line of evidence, in addition to the number of small, slender incisiform teeth in the dentary, as based on tooth sockets. Specifically, the paper's T. rex was distinguished by robust anatomy, a moderate ratio of femur length vs circumference, and the possession of a singular slender incisiform dentary tooth; T. imperator was considered to be robust with a small femur length to circumference ratio and two of the slender teeth; and T. regina was a gracile form with a high femur ratio and one of the slender teeth. It was observed that variation in proportions and robustness became more extreme higher up in the sample, stratigraphically. This was interpreted as a single earlier population, T. imperator, speciating into more than one taxon, T. rex and T. regina.

However, several other leading paleontologists, including Stephen Brusatte, Thomas Carr, Thomas Holtz, David Hone, Jingmai O'Connor, and Lindsay Zanno, criticized the study or expressed skepticism of its conclusions when approached by various media outlets for comment. Their criticism was subsequently published in a technical paper. Holtz and Zanno both remarked that it was plausible that more than one species of Tyrannosaurus existed, but felt the new study was insufficient to support the species it proposed. Holtz remarked that, even if Tyrannosaurus imperator represented a distinct species from Tyrannosaurus rex, it may represent the same species as Nanotyrannus lancensis and would need to be called Tyrannosaurus lancensis. O'Connor, a curator at the Field Museum, where the T. imperator holotype Sue is displayed, regarded the new species as too poorly-supported to justify modifying the exhibit signs. Brusatte, Carr, and O'Connor viewed the distinguishing features proposed between the species as reflecting natural variation within a species. Both Carr and O'Connor expressed concerns about the study's inability to determine which of the proposed species several well-preserved specimens belonged to. Another paleontologist, Philip J. Currie, originally co-authored the study but withdrew from it as he did not want to be involved in naming the new species.

Paul rejected the objections raised by critics, insisting that they are unwilling to consider that Tyrannosaurus might represent more than one species. In a subsequent paper awaiting publication, Paul maintained the conclusion that Tyrannosaurus consists of three species. He pointed out that the criticism of the study naming T. imperator and T. regina only focused on two of the features used to distinguish the two new species (the number of small incisiform teeth and femur robustness), while the original study also compared the robustness of other bones as well (the maxilla, dentary, humerus, ilium and metatarsals). Furthermore, Paul argued that Tyrannosaurus can be separated into three different species based on the shape of knob-like bumps ('postorbital bosses') behind the eyes. Paul also argued that past research concluding that Tyrannosaurus only consists of one species ( T. rex) has simply assumed that all Tyrannosaurus skeletons are a single species, and that many new dinosaur species have been named on the basis of fewer differences than he and his colleagues used when proposing T. imperator and T. regina.

Former holotype of Nanotyrannus lancensis, now interpreted as a juvenile Tyrannosaurus

Other tyrannosaurid fossils found in the same formations as T. rex were originally classified as separate taxa, including Aublysodon and Albertosaurus megagracilis, the latter being named Dinotyrannus megagracilis in 1995. These fossils are now universally considered to belong to juvenile T. rex. A small but nearly complete skull from Montana, 60 centimeters (2.0 ft) long, might be an exception. This skull, CMNH 7541, was originally classified as a species of Gorgosaurus ( G. lancensis) by Charles W. Gilmore in 1946. In 1988, the specimen was re-described by Robert T. Bakker, Phil Currie, and Michael Williams, then the curator of paleontology at the Cleveland Museum of Natural History, where the original specimen was housed and is now on display. Their initial research indicated that the skull bones were fused, and that it therefore represented an adult specimen. In light of this, Bakker and colleagues assigned the skull to a new genus named Nanotyrannus (meaning "dwarf tyrant", for its apparently small adult size). The specimen is estimated to have been around 5.2 meters (17 ft) long when it died. However, In 1999, a detailed analysis by Thomas Carr revealed the specimen to be a juvenile, leading Carr and many other paleontologists to consider it a juvenile T. rex individual.

In 2001, a more complete juvenile tyrannosaur (nicknamed " Jane", catalog number BMRP 2002.4.1), belonging to the same species as the original Nanotyrannus specimen, was uncovered. This discovery prompted a conference on tyrannosaurs focused on the issues of Nanotyrannus validity at the Burpee Museum of Natural History in 2005. Several paleontologists who had previously published opinions that N. lancensis was a valid species, including Currie and Williams, saw the discovery of "Jane" as a confirmation that Nanotyrannus was, in fact, a juvenile T. rex. Peter Larson continued to support the hypothesis that N. lancensis was a separate but closely related species, based on skull features such as two more teeth in both jaws than T. rex; as well as proportionately larger hands with phalanges on the third metacarpal and different wishbone anatomy in an undescribed specimen. He also argued that Stygivenator, generally considered to be a juvenile T. rex, may be a younger Nanotyrannus specimen. Later research revealed that other tyrannosaurids such as Gorgosaurus also experienced reduction in tooth count during growth, and given the disparity in tooth count between individuals of the same age group in this genus and Tyrannosaurus, this feature may also be due to individual variation. In 2013, Carr noted that all of the differences claimed to support Nanotyrannus have turned out to be individually or ontogenetically variable features or products of distortion of the bones.

In 2016, analysis of limb proportions by Persons and Currie suggested Nanotyrannus specimens to have differing cursoriality levels, potentially separating it from T. rex. However, paleontologist Manabu Sakomoto has commented that this conclusion may be impacted by low sample size, and the discrepancy does not necessarily reflect taxonomic distinction. In 2016, Joshua Schmerge argued for Nanotyrannus' validity based on skull features, including a dentary groove in BMRP 2002.4.1's skull. According to Schmerge, as that feature is absent in T. rex and found only in Dryptosaurus and albertosaurines, this suggests Nanotyrannus is a distinct taxon within the Albertosaurinae. The same year, Carr and colleagues noted that this was not sufficient enough to clarify Nanotyrannus' validity or classification, being a common and ontogenetically variable feature among tyrannosauroids.

A 2020 study by Holly Woodward and colleagues showed the specimens referred to Nanotyrannus were all ontogenetically immature and found it probable that these specimens belonged to T. rex. The same year, Carr published a paper on T. rex's growth history, finding that CMNH 7541 fit within the expected ontogenetic variation of the taxon and displayed juvenile characteristics found in other specimens. It was classified as a juvenile, under 13 years old with a skull less than 80 cm (31 in). No significant sexual or phylogenetic variation was discernible among any of the 44 specimens studied, with Carr stating that characters of potential phylogenetic importance decrease throughout age at the same rate as growth occurs. Discussing the paper's results, Carr described how all " Nanotyrannus" specimens formed a continual growth transition between the smallest juveniles and the subadults, unlike what would be expected if it were a distinct taxon where the specimens would group to the exclusion of Tyrannosaurus. Carr concluded that "the 'nanomorphs' are not all that similar to each other and instead form an important bridge in the growth series of T. rex that captures the beginnings of the profound change from the shallow skull of juveniles to the deep skull that is seen in fully-developed adults."

Paleobiology

Life history

The identification of several specimens as juvenile T. rex has allowed scientists to document ontogenetic changes in the species, estimate the lifespan, and determine how quickly the animals would have grown. The smallest known individual ( LACM 28471, the "Jordan theropod") is estimated to have weighed only 30 kg (66 lb), while the largest, such as FMNH PR2081 (Sue) most likely weighed about 5,650 kg (12,460 lb). Histologic analysis of T. rex bones showed LACM 28471 had aged only 2 years when it died, while Sue was 28 years old, an age which may have been close to the maximum for the species.

Histology has also allowed the age of other specimens to be determined. Growth curves can be developed when the ages of different specimens are plotted on a graph along with their mass. A T. rex growth curve is S-shaped, with juveniles remaining under 1,800 kg (4,000 lb) until approximately 14 years of age, when body size began to increase dramatically. During this rapid growth phase, a young T. rex would gain an average of 600 kg (1,300 lb) a year for the next four years. At 18 years of age, the curve plateaus again, indicating that growth slowed dramatically. For example, only 600 kg (1,300 lb) separated the 28-year-old Sue from a 22-year-old Canadian specimen ( RTMP 81.12.1). A 2004 histological study performed by different workers corroborates these results, finding that rapid growth began to slow at around 16 years of age.

A study by Hutchinson and colleagues in 2011 corroborated the previous estimation methods in general, but their estimation of peak growth rates is significantly higher; it found that the "maximum growth rates for T. rex during the exponential stage are 1790 kg/year". Although these results were much higher than previous estimations, the authors noted that these results significantly lowered the great difference between its actual growth rate and the one which would be expected of an animal of its size. The sudden change in growth rate at the end of the growth spurt may indicate physical maturity, a hypothesis which is supported by the discovery of medullary tissue in the femur of a 16 to 20-year-old T. rex from Montana ( MOR 1125, also known as B-rex). Medullary tissue is found only in female birds during ovulation, indicating that B-rex was of reproductive age. Further study indicates an age of 18 for this specimen. In 2016, it was finally confirmed by Mary Higby Schweitzer and Lindsay Zanno and colleagues that the soft tissue within the femur of MOR 1125 was medullary tissue. This also confirmed the identity of the specimen as a female. The discovery of medullary bone tissue within Tyrannosaurus may prove valuable in determining the sex of other dinosaur species in future examinations, as the chemical makeup of medullary tissue is unmistakable. Other tyrannosaurids exhibit extremely similar growth curves, although with lower growth rates corresponding to their lower adult sizes.

An additional study published in 2020 by Woodward and colleagues, for the journal Science Advances indicates that during their growth from juvenile to adult, Tyrannosaurus was capable of slowing down its growth to counter environmental factors such as lack of food. The study, focusing on two juvenile specimens between 13 and 15 years old housed at the Burpee Museum in Illinois, indicates that the rate of maturation for Tyrannosaurus was dependent on resource abundance. This study also indicates that in such changing environments, Tyrannosaurus was particularly well-suited to an environment that shifted yearly in regards to resource abundance, hinting that other midsize predators might have had difficulty surviving in such harsh conditions and explaining the niche partitioning between juvenile and adult tyrannosaurs. The study further indicates that Tyrannosaurus and the dubious genus Nanotyrannus are synonymous, due to analysis of the growth rings in the bones of the two specimens studied.

Over half of the known T. rex specimens appear to have died within six years of reaching sexual maturity, a pattern which is also seen in other tyrannosaurs and in some large, long-lived birds and mammals today. These species are characterized by high infant mortality rates, followed by relatively low mortality among juveniles. Mortality increases again following sexual maturity, partly due to the stresses of reproduction. One study suggests that the rarity of juvenile T. rex fossils is due in part to low juvenile mortality rates; the animals were not dying in large numbers at these ages, and thus were not often fossilized. This rarity may also be due to the incompleteness of the fossil record or to the bias of fossil collectors towards larger, more spectacular specimens. In a 2013 lecture, Thomas Holtz Jr. suggested that dinosaurs "lived fast and died young" because they reproduced quickly whereas mammals have long life spans because they take longer to reproduce. Gregory S. Paul also writes that Tyrannosaurus reproduced quickly and died young, but attributes their short life spans to the dangerous lives they lived.

Skin and possible filamentous feathering

The discovery of feathered dinosaurs led to debate regarding whether, and to what extent, Tyrannosaurus might have been feathered. Filamentous structures, which are commonly recognized as the precursors of feathers, have been reported in the small-bodied, basal tyrannosauroid Dilong paradoxus from the Early Cretaceous Yixian Formation of China in 2004. Because integumentary impressions of larger tyrannosauroids known at that time showed evidence of scales, the researchers who studied Dilong speculated that insulating feathers might have been lost by larger species due to their smaller surface-to-volume ratio. The subsequent discovery of the giant species Yutyrannus huali, also from the Yixian, showed that even some large tyrannosauroids had feathers covering much of their bodies, casting doubt on the hypothesis that they were a size-related feature. A 2017 study reviewed known skin impressions of tyrannosaurids, including those of a Tyrannosaurus specimen nicknamed "Wyrex" (BHI 6230) which preserves patches of mosaic scales on the tail, hip, and neck. The study concluded that feather covering of large tyrannosaurids such as Tyrannosaurus was, if present, limited to the upper side of the trunk.

A conference abstract published in 2016 posited that theropods such as Tyrannosaurus had their upper teeth covered in lips, instead of bare teeth as seen in crocodilians. This was based on the presence of enamel, which according to the study needs to remain hydrated, an issue not faced by aquatic animals like crocodilians. However, there has been criticism where it favors the idea for lips, with the 2017 analytical study proposing that tyrannosaurids had large, flat scales on their snouts instead of lips just like modern crocodiles. But crocodiles possess rather cracked keratinized skin, not flat scales; by observing the hummocky rugosity of tyrannosaurids, and comparing it to extant lizards, researchers have found that tyrannosaurids had squamose scales rather than a crocodillian-like skin.

In 2023, Cullen and colleagues supported the idea that theropods like tyrannosaurids had lips based on anatomical patterns, such as those of the foramina on their face and jaws, more similar to those of modern squamates such as monitor lizards or marine iguanas than those of modern crocodilians like alligators. By comparatively analysing the dentition of Daspletosaurus and the American alligator, it was shown that the enamel of tyrannosaurids had no significant wear, while that of modern crocodilians had erosion on the labial side and substantial wear. This suggests that it is likely that theropod teeth existed under hydrated conditions (i.e. extraoral tissues). On the basis of the relationship between hydration and wear resistance, the authors argued that it is unlikely that the teeth of theropods including tyrannosaurids would have remained unworn when exposed for a long time, as it would have been difficult to maintain hydration. The authors also performed regression analyses to demonstrate the relationship between tooth height and skull length, and found that varanids like the crocodile monitor had substantially greater tooth height-to-skull length ratios than Tyrannosaurus, indicating that the teeth of theropods were not too big to be covered by extraoral tissues when the mouth was closed.

Sexual dimorphism

As the number of known specimens increased, scientists began to analyze the variation between individuals and discovered what appeared to be two distinct body types, or morphs, similar to some other theropod species. As one of these morphs was more solidly built, it was termed the 'robust' morph while the other was termed ' gracile'. Several morphological differences associated with the two morphs were used to analyze sexual dimorphism in T. rex, with the 'robust' morph usually suggested to be female. For example, the pelvis of several 'robust' specimens seemed to be wider, perhaps to allow the passage of eggs. It was also thought that the 'robust' morphology correlated with a reduced chevron on the first tail vertebra, also ostensibly to allow eggs to pass out of the reproductive tract, as had been erroneously reported for crocodiles.

In recent years, evidence for sexual dimorphism has been weakened. A 2005 study reported that previous claims of sexual dimorphism in crocodile chevron anatomy were in error, casting doubt on the existence of similar dimorphism between T. rex sexes. A full-sized chevron was discovered on the first tail vertebra of Sue, an extremely robust individual, indicating that this feature could not be used to differentiate the two morphs anyway. As T. rex specimens have been found from Saskatchewan to New Mexico, differences between individuals may be indicative of geographic variation rather than sexual dimorphism. The differences could also be age-related, with 'robust' individuals being older animals.

Only a single Tyrannosaurus specimen has been conclusively shown to belong to a specific sex. Examination of B-rex demonstrated the preservation of soft tissue within several bones. Some of this tissue has been identified as a medullary tissue, a specialized tissue grown only in modern birds as a source of calcium for the production of eggshell during ovulation. As only female birds lay eggs, medullary tissue is only found naturally in females, although males are capable of producing it when injected with female reproductive hormones like estrogen. This strongly suggests that B-rex was female and that she died during ovulation. Recent research has shown that medullary tissue is never found in crocodiles, which are thought to be the closest living relatives of dinosaurs. The shared presence of medullary tissue in birds and other theropod dinosaurs is further evidence of the close evolutionary relationship between the two.

Like many bipedal dinosaurs, T. rex was historically depicted as a 'living tripod', with the body at 45 degrees or less from the vertical and the tail dragging along the ground, similar to a kangaroo. This concept dates from Joseph Leidy's 1865 reconstruction of Hadrosaurus, the first to depict a dinosaur in a bipedal posture. In 1915, convinced that the creature stood upright, Henry Fairfield Osborn, former president of the American Museum of Natural History, further reinforced the notion in unveiling the first complete T. rex skeleton arranged this way. It stood in an upright pose for 77 years, until it was dismantled in 1992.

By 1970, scientists realized this pose was incorrect and could not have been maintained by a living animal, as it would have resulted in the dislocation or weakening of several joints, including the hips and the articulation between the head and the spinal column. The inaccurate AMNH mount inspired similar depictions in many films and paintings (such as Rudolph Zallinger's famous mural The Age of Reptiles in Yale University's Peabody Museum of Natural History) until the 1990s, when films such as Jurassic Park introduced a more accurate posture to the general public. Modern representations in museums, art, and film show T. rex with its body approximately parallel to the ground with the tail extended behind the body to balance the head.

To sit down, Tyrannosaurus may have settled its weight backwards and rested its weight on a pubic boot, the wide expansion at the end of the pubis in some dinosaurs. With its weight rested on the pelvis, it may have been free to move the hindlimbs. Getting back up again might have involved some stabilization from the diminutive forelimbs. The latter known as Newman's pushup theory has been debated. Nonetheless, Tyrannosaurus was probably able to get up if it fell, which only would have required placing the limbs below the center of gravity, with the tail as an effective counterbalance. Healed stress fractures in the forelimbs have been put forward both as evidence that the arms cannot have been very useful and as evidence that they were indeed used and acquired wounds, like the rest of the body.

When T. rex was first discovered, the humerus was the only element of the forelimb known. For the initial mounted skeleton as seen by the public in 1915, Osborn substituted longer, three-fingered forelimbs like those of Allosaurus. A year earlier, Lawrence Lambe described the short, two-fingered forelimbs of the closely related Gorgosaurus. This strongly suggested that T. rex had similar forelimbs, but this hypothesis was not confirmed until the first complete T. rex forelimbs were identified in 1989, belonging to MOR 555 (the "Wankel rex"). The remains of Sue also include complete forelimbs. T. rex arms are very small relative to overall body size, measuring only 1 meter (3.3 ft) long, and some scholars have labelled them as vestigial. However, the bones show large areas for muscle attachment, indicating considerable strength. This was recognized as early as 1906 by Osborn, who speculated that the forelimbs may have been used to grasp a mate during copulation. Newman (1970) suggested that the forelimbs were used to assist Tyrannosaurus in rising from a prone position. Since then, other functions have been proposed, although some scholars find them implausible. Padian (2022) argued that the reduction of the arms in tyrannosaurids did not serve a particular function but was a secondary adaptation, stating that as tyrannosaurids developed larger and more powerful skulls and jaws, the arms got smaller to avoid being bitten or torn by other individuals, particularly during group feedings.

Another possibility is that the forelimbs held struggling prey while it was killed by the tyrannosaur's enormous jaws. This hypothesis may be supported by biomechanical analysis. T. rex forelimb bones exhibit extremely thick cortical bone, which has been interpreted as evidence that they were developed to withstand heavy loads. The biceps brachii muscle of an adult T. rex was capable of lifting 199 kilograms (439 lb) by itself; other muscles such as the brachialis would work along with the biceps to make elbow flexion even more powerful. The M. biceps muscle of T. rex was 3.5 times as powerful as the human equivalent. A T. rex forearm had a limited range of motion, with the shoulder and elbow joints allowing only 40 and 45 degrees of motion, respectively. In contrast, the same two joints in Deinonychus allow up to 88 and 130 degrees of motion, respectively, while a human arm can rotate 360 degrees at the shoulder and move through 165 degrees at the elbow. The heavy build of the arm bones, strength of the muscles, and limited range of motion may indicate a system evolved to hold fast despite the stresses of a struggling prey animal. In the first detailed scientific description of Tyrannosaurus forelimbs, paleontologists Kenneth Carpenter and Matt Smith dismissed notions that the forelimbs were useless or that Tyrannosaurus was an obligate scavenger.

The idea that the arms served as weapons when hunting prey have also been proposed by Steven M. Stanley, who suggested that the arms were used for slashing prey, especially by using the claws to rapidly inflict long, deep gashes to its prey. This was dismissed by Padian, who have argued that Stanley based his conclusion on incorrectly estimated forelimb size and range of motion.

Thermoregulation

Tyrannosaurus, like most dinosaurs, was long thought to have an ectothermic ("cold-blooded") reptilian metabolism. The idea of dinosaur ectothermy was challenged by scientists like Robert T. Bakker and John Ostrom in the early years of the " Dinosaur Renaissance", beginning in the late 1960s. T. rex itself was claimed to have been endothermic ("warm-blooded"), implying a very active lifestyle. Since then, several paleontologists have sought to determine the ability of Tyrannosaurus to regulate its body temperature. Histological evidence of high growth rates in young T. rex, comparable to those of mammals and birds, may support the hypothesis of a high metabolism. Growth curves indicate that, as in mammals and birds, T. rex growth was limited mostly to immature animals, rather than the indeterminate growth seen in most other vertebrates.

Oxygen isotope ratios in fossilized bone are sometimes used to determine the temperature at which the bone was deposited, as the ratio between certain isotopes correlates with temperature. In one specimen, the isotope ratios in bones from different parts of the body indicated a temperature difference of no more than 4 to 5 °C (7 to 9 °F) between the vertebrae of the torso and the tibia of the lower leg. This small temperature range between the body core and the extremities was claimed by paleontologist Reese Barrick and geochemist William Showers to indicate that T. rex maintained a constant internal body temperature ( homeothermy) and that it enjoyed a metabolism somewhere between ectothermic reptiles and endothermic mammals. Other scientists have pointed out that the ratio of oxygen isotopes in the fossils today does not necessarily represent the same ratio in the distant past, and may have been altered during or after fossilization ( diagenesis). Barrick and Showers have defended their conclusions in subsequent papers, finding similar results in another theropod dinosaur from a different continent and tens of millions of years earlier in time (Giganotosaurus). Ornithischian dinosaurs also showed evidence of homeothermy, while varanid lizards from the same formation did not. In 2022, Wiemann and colleagues used a different approach-the spectroscopy of lipoxidation signals, which are byproducts of oxidative phosphorylation and correlate with metabolic rates-to show that various dinosaur genera including Tyrannosaurus had endothermic metabolisms, on par with that of modern birds and higher than that of mammals. They also suggested that such a metabolism was ancestrally common to all dinosaurs.

Even if T. rex does exhibit evidence of homeothermy, it does not necessarily mean that it was endothermic. Such thermoregulation may also be explained by gigantothermy, as in some living sea turtles. Similar to contemporary crocodilians, openings (dorsotemporal fenestrae) in the skull roofs of Tyrannosaurus may have aided thermoregulation.

Soft tissue

In the March 2005 issue of , Mary Higby Schweitzer of North Carolina State University and colleagues announced the recovery of soft tissue from the marrow cavity of a fossilized leg bone from a T. rex. The bone had been intentionally, though reluctantly, broken for shipping and then not preserved in the normal manner, specifically because Schweitzer was hoping to test it for soft tissue. Designated as the Museum of the Rockies specimen 1125, or MOR 1125, the dinosaur was previously excavated from the Hell Creek Formation. Flexible, bifurcating blood vessels and fibrous but elastic bone matrix tissue were recognized. In addition, microstructures resembling blood cells were found inside the matrix and vessels. The structures bear resemblance to ostrich blood cells and vessels. Whether an unknown process, distinct from normal fossilization, preserved the material, or the material is original, the researchers do not know, and they are careful not to make any claims about preservation. If it is found to be original material, any surviving proteins may be used as a means of indirectly guessing some of the DNA content of the dinosaurs involved, because each protein is typically created by a specific gene. The absence of previous finds may be the result of people assuming preserved tissue was impossible, therefore not looking. Since the first, two more tyrannosaurs and a hadrosaur have also been found to have such tissue-like structures. Research on some of the tissues involved has suggested that birds are closer relatives to tyrannosaurs than other modern animals.

In studies reported in Science in April 2007, Asara and colleagues concluded that seven traces of collagen proteins detected in purified T. rex bone most closely match those reported in chickens, followed by frogs and newts. The discovery of proteins from a creature tens of millions of years old, along with similar traces the team found in a mastodon bone at least 160,000 years old, upends the conventional view of fossils and may shift paleontologists' focus from bone hunting to biochemistry. Until these finds, most scientists presumed that fossilization replaced all living tissue with inert minerals. Paleontologist Hans Larsson of McGill University in Montreal, who was not part of the studies, called the finds "a milestone", and suggested that dinosaurs could "enter the field of molecular biology and really slingshot paleontology into the modern world".

The presumed soft tissue was called into question by Thomas Kaye of the University of Washington and his co-authors in 2008. They contend that what was really inside the tyrannosaur bone was slimy biofilm created by bacteria that coated the voids once occupied by blood vessels and cells. The researchers found that what previously had been identified as remnants of blood cells, because of the presence of iron, were actually framboids, microscopic mineral spheres bearing iron. They found similar spheres in a variety of other fossils from various periods, including an ammonite. In the ammonite, they found the spheres in a place where the iron they contain could not have had any relationship to the presence of blood. Schweitzer has strongly criticized Kaye's claims and argues that there is no reported evidence that biofilms can produce branching, hollow tubes like those noted in her study. San Antonio, Schweitzer and colleagues published an analysis in 2011 of what parts of the collagen had been recovered, finding that it was the inner parts of the collagen coil that had been preserved, as would have been expected from a long period of protein degradation. Other research challenges the identification of soft tissue as biofilm and confirms finding "branching, vessel-like structures" from within fossilized bone.

Scientists have produced a wide range of possible maximum running speeds for Tyrannosaurus: mostly around 9 meters per second (32 km/h; 20 mph), but as low as 4.5-6.8 meters per second (16-24 km/h; 10-15 mph) and as high as 20 meters per second (72 km/h; 45 mph), though it running this speed is very unlikely. Tyrannosaurus was a bulky and heavy carnivore so it is unlikely to run very fast at all compared to other theropods like Carnotaurus or Giganotosaurus. Researchers have relied on various estimating techniques because, while there are many tracks of large theropods walking, none showed evidence of running.

A 2002 report used a mathematical model (validated by applying it to three living animals: alligators, chickens, and humans; and eight more species, including emus and ostriches) to gauge the leg muscle mass needed for fast running (over 40 km/h or 25 mph). Scientists who think that Tyrannosaurus was able to run point out that hollow bones and other features that would have lightened its body may have kept adult weight to a mere 4.5 metric tons (5.0 short tons) or so, or that other animals like ostriches and horses with long, flexible legs are able to achieve high speeds through slower but longer strides. Proposed top speeds exceeded 40 kilometers per hour (25 mph) for Tyrannosaurus, but were deemed infeasible because they would require exceptional leg muscles of approximately 40-86% of total body mass. Even moderately fast speeds would have required large leg muscles. If the muscle mass was less, only 18 kilometers per hour (11 mph) for walking or jogging would have been possible. Holtz noted that tyrannosaurids and some closely related groups had significantly longer distal hindlimb components (shin plus foot plus toes) relative to the femur length than most other theropods, and that tyrannosaurids and their close relatives had a tightly interlocked metatarsus (foot bones). The third metatarsal was squeezed between the second and fourth metatarsals to form a single unit called an arctometatarsus. This ankle feature may have helped the animal to run more efficiently. Together, these leg features allowed Tyrannosaurus to transmit locomotory forces from the foot to the lower leg more effectively than in earlier theropods.

Only known tyrannosaurid trackway (Bellatoripes fredlundi), from the Wapiti Formation, British Columbia

Additionally, a 2020 study indicates that Tyrannosaurus and other tyrannosaurids were exceptionally efficient walkers. Studies by Dececchi et al., compared the leg proportions, body mass, and the gaits of more than 70 species of theropod dinosaurs including Tyrannosaurus and its relatives. The research team then applied a variety of methods to estimate each dinosaur's top speed when running as well as how much energy each dinosaur expended while moving at more relaxed speeds such as when walking. Among smaller to medium-sized species such as dromaeosaurids, longer legs appear to be an adaptation for faster running, in line with previous results by other researchers. But for theropods weighing over 1,000 kg (2,200 lb), top running speed is limited by body size, so longer legs instead were found to have correlated with low-energy walking. The results further indicate that smaller theropods evolved long legs as a means to both aid in hunting and escape from larger predators while larger theropods that evolved long legs did so to reduce the energy costs and increase foraging efficiency, as they were freed from the demands of predation pressure due to their role as apex predators. Compared to more basal groups of theropods in the study, tyrannosaurs like Tyrannosaurus itself showed a marked increase in foraging efficiency due to reduced energy expenditures during hunting or scavenging. This in turn likely resulted in tyrannosaurs having a reduced need for hunting forays and requiring less food to sustain themselves as a result. Additionally, the research, in conjunction with studies that show tyrannosaurs were more agile than other large-bodied theropods, indicates they were quite well-adapted to a long-distance stalking approach followed by a quick burst of speed to go for the kill. Analogies can be noted between tyrannosaurids and modern wolves as a result, supported by evidence that at least some tyrannosaurids were hunting in group settings.

A study published in 2021 by Pasha van Bijlert et al., calculated the preferred walking speed of Tyrannosaurus, reporting a speed of 1.28 meters per second (4.6 km/h; 2.9 mph). While walking, animals reduce their energy expenditure by choosing certain step rhythms at which their body parts resonate. The same would have been true for dinosaurs, but previous studies did not fully account for the impact the tail had on their walking speeds. According to the authors, when a dinosaur walked, its tail would slightly sway up and down with each step as a result of the interspinous ligaments suspending the tail. Like rubber bands, these ligaments stored energy when they are stretched due to the swaying of the tail. Using a 3-D model of Tyrannosaurus specimen Trix, muscles and ligaments were reconstructed to simulate the tail movements. This results in a rhythmic, energy-efficient walking speed for Tyrannosaurus similar to that seen in living animals such as humans, ostriches and giraffes.

A 2017 study estimated the top running speed of Tyrannosaurus as 17 mph (27 km/h), speculating that Tyrannosaurus exhausted its energy reserves long before reaching top speed, resulting in a parabola-like relationship between size and speed. Another 2017 study hypothesized that an adult Tyrannosaurus was incapable of running due to high skeletal loads. Using a calculated weight estimate of 7 tons, the model showed that speeds above 11 mph (18 km/h) would have probably shattered the leg bones of Tyrannosaurus. The finding may mean that running was also not possible for other giant theropod dinosaurs like Giganotosaurus, Mapusaurus and Acrocanthosaurus. However, studies by Eric Snively and colleagues, published in 2019 indicate that Tyrannosaurus and other tyrannosaurids were more maneuverable than allosauroids and other theropods of comparable size due to low rotational inertia compared to their body mass combined with large leg muscles. As a result, it is hypothesized that Tyrannosaurus was capable of making relatively quick turns and could likely pivot its body more quickly when close to its prey, or that while turning, the theropod could "pirouette" on a single planted foot while the alternating leg was held out in a suspended swing during a pursuit. The results of this study potentially could shed light on how agility could have contributed to the success of tyrannosaurid evolution.

Depiction of Tyrannosaurus rising from the ground, based on fossil tracks described in 2021.

Rare fossil footprints and trackways found in New Mexico and Wyoming that are assigned to the ichnogenus Tyrannosauripus have been attributed to being made by Tyrannosaurus, based on the stratigraphic age of the rocks they are preserved in. The first specimen, found in 1994 was described by Lockley and Hunt and consists of a single, large footprint. Another pair of ichnofossils, described in 2021, show a large tyrannosaurid rising from a prone position by rising up using its elbows in conjunction with the pads on their feet to stand. These two unique sets of fossils were found in Ludlow, Colorado and Cimarron, New Mexico. Another ichnofossil described in 2018, perhaps belonging to a juvenile Tyrannosaurus or the dubious genus Nanotyrannus was uncovered in the Lance Formation of Wyoming. The trackway itself offers a rare glimpse into the walking speed of tyrannosaurids, and the trackmaker is estimated to have been moving at a speed of 4.5-8.0 kilometers per hour (2.8-5.0 mph), significantly faster than previously assumed for estimations of walking speed in tyrannosaurids.

Brain and senses

The eye-sockets faced mainly forwards, giving it good binocular vision (Sue specimen).

A study conducted by Lawrence Witmer and Ryan Ridgely of Ohio University found that Tyrannosaurus shared the heightened sensory abilities of other coelurosaurs, highlighting relatively rapid and coordinated eye and head movements; an enhanced ability to sense low frequency sounds, which would allow tyrannosaurs to track prey movements from long distances; and an enhanced sense of smell. A study published by Kent Stevens concluded that Tyrannosaurus had keen vision. By applying modified perimetry to facial reconstructions of several dinosaurs including Tyrannosaurus, the study found that Tyrannosaurus had a binocular range of 55 degrees, surpassing that of modern hawks. Stevens estimated that Tyrannosaurus had 13 times the visual acuity of a human and surpassed the visual acuity of an eagle, which is 3.6 times that of a person. Stevens estimated a limiting far point (that is, the distance at which an object can be seen as separate from the horizon) as far as 6 km (3.7 mi) away, which is greater than the 1.6 km (1 mi) that a human can see.

Thomas Holtz Jr. would note that high depth perception of Tyrannosaurus may have been due to the prey it had to hunt, noting that it had to hunt ceratopsians such as Triceratops, ankylosaurs such as Ankylosaurus, and hadrosaurs. He would suggest that this made precision more crucial for Tyrannosaurus enabling it to, "get in, get that blow in and take it down." In contrast, Acrocanthosaurus had limited depth perception because they hunted large sauropods, which were relatively rare during the time of Tyrannosaurus.

Tyrannosaurus had very large olfactory bulbs and olfactory nerves relative to their brain size, the organs responsible for a heightened sense of smell. This suggests that the sense of smell was highly developed, and implies that tyrannosaurs could detect carcasses by scent alone across great distances. The sense of smell in tyrannosaurs may have been comparable to modern vultures, which use scent to track carcasses for scavenging. Research on the olfactory bulbs has shown that T. rex had the most highly developed sense of smell of 21 sampled non-avian dinosaur species.

Somewhat unusually among theropods, T. rex had a very long cochlea. The length of the cochlea is often related to hearing acuity, or at least the importance of hearing in behavior, implying that hearing was a particularly important sense to tyrannosaurs. Specifically, data suggests that T. rex heard best in the low-frequency range, and that low-frequency sounds were an important part of tyrannosaur behavior. A 2017 study by Thomas Carr and colleagues found that the snout of tyrannosaurids was highly sensitive, based on a high number of small openings in the facial bones of the related Daspletosaurus that contained sensory neurons. The study speculated that tyrannosaurs might have used their sensitive snouts to measure the temperature of their nests and to gently pick up eggs and hatchlings, as seen in modern crocodylians. Another study published in 2021 further suggests that Tyrannosaurus had an acute sense of touch, based on neurovascular canals in the front of its jaws, which it could utilize to better detect and consume prey. The study, published by Kawabe and Hittori et al., suggests that Tyrannosaurus could also accurately sense slight differences in material and movement, allowing it to utilize different feeding strategies on different parts of its prey's carcasses depending on the situation. The sensitive neurovascular canals of Tyrannosaurus also likely were adapted to performing fine movements and behaviors such as nest building, parental care, and other social behavior such as intraspecific communication. The results of this study also align with results made in studying the related tyrannosaurid Daspletosaurus horneri and the allosauroid Neovenator, which have similar neurovascular adaptations, suggesting that the faces of theropods were highly sensitive to pressure and touch. However, a more recent study reviewing the evolution of the trigeminal canals among sauropsids notes that a much denser network of neurovascular canals in the snout and lower jaw is more commonly encountered in aquatic or semiaquatic taxa (e.g., Spinosaurus, Halszkaraptor, Plesiosaurus), and taxa that developed a rhamphotheca (e.g., Caenagnathasia), while the network of canals in Tyrannosaurus appears simpler, though still more derived than in most ornithischians, and overall terrestrial taxa such as tyrannosaurids and Neovenator may have had average facial sensitivity for non-edentulous terrestrial theropods, although further research is needed. The neurovascular canals in Tyrannosaurus may instead have supported soft tissue structures for thermoregulation or social signaling, the latter of which could be confirmed by the fact that the neurovascular network of canals may have changed during ontogeny.

A study by Grant R. Hurlburt, Ryan C. Ridgely and Lawrence Witmer obtained estimates for Encephalization Quotients (EQs), based on reptiles and birds, as well as estimates for the ratio of cerebrum to brain mass. The study concluded that Tyrannosaurus had the relatively largest brain of all adult non-avian dinosaurs with the exception of certain small maniraptoriforms (Bambiraptor, and Ornithomimus). The study found that Tyrannosaurus's relative brain size was still within the range of modern reptiles, being at most 2 standard deviations above the mean of non-avian reptile EQs. The estimates for the ratio of cerebrum mass to brain mass would range from 47.5 to 49.53 percent. According to the study, this is more than the lowest estimates for extant birds (44.6 percent), but still close to the typical ratios of the smallest sexually mature alligators which range from 45.9-47.9 percent. Other studies, such as those by Steve Brusatte, indicate the encephalization quotient of Tyrannosaurus was similar in range (2.0-2.4) to a chimpanzee (2.2-2.5), though this may be debatable as reptilian and mammalian encephalization quotients are not equivalent.

Social behavior

Philip J. Currie suggested that Tyrannosaurus may have been pack hunters, comparing T. rex to related species Tarbosaurus bataar and Albertosaurus sarcophagus, citing fossil evidence that may indicate gregarious (describing animals that travel in herds or packs) behavior. A find in South Dakota where three T. rex skeletons were in close proximity may suggest the formation of a pack. Cooperative pack hunting may have been an effective strategy for subduing prey with advanced anti-predator adaptations which pose potential lethality such as Triceratops and Ankylosaurus.

Currie's pack-hunting T. rex hypothesis has been criticized for not having been peer-reviewed, but rather was discussed in a television interview and book called Dino Gangs. The Currie theory for pack hunting by T. rex is based mainly by analogy to a different species, Tarbosaurus bataar. Evidence of gregariousness in T. bataar itself has not been peer-reviewed, and to Currie's own admission, can only be interpreted with reference to evidence in other closely related species. According to Currie gregariousness in Albertosaurus sarcophagus is supported by the discovery of 26 individuals with varied ages in the Dry Island bonebed. He ruled out the possibility of a predator trap due to the similar preservation state of individuals and the near absence of herbivores.

Additional support of tyrannosaurid gregariousness can be found in fossilized trackways from the Upper Cretaceous Wapiti Formation of northeastern British Columbia, Canada, left by three tyrannosaurids traveling in the same direction. According to scientists assessing the Dino Gangs program, the evidence for pack hunting in Tarbosaurus and Albertosaurus is weak and based on group skeletal remains for which alternate explanations may apply (such as drought or a flood forcing dinosaurs to die together in one place). Others researchers have speculated that instead of large theropod social groups, some of these finds represent behavior more akin to Komodo dragon-like mobbing of carcasses, even going as far as to say true pack-hunting behavior may not exist in any non-avian dinosaurs due to its rarity in modern predators.

Evidence of intraspecific attack was found by Joseph Peterson and his colleagues in the juvenile Tyrannosaurus nicknamed Jane. Peterson and his team found that Jane's skull showed healed puncture wounds on the upper jaw and snout which they believe came from another juvenile Tyrannosaurus. Subsequent CT scans of Jane's skull would further confirm the team's hypothesis, showing that the puncture wounds came from a traumatic injury and that there was subsequent healing. The team would also state that Jane's injuries were structurally different from the parasite-induced lesions found in Sue and that Jane's injuries were on its face whereas the parasite that infected Sue caused lesions to the lower jaw.

Feeding strategies

Tyrannosaurus tooth marks on bones of various herbivorous dinosaurs

A Tyrannosaurus mounted next to a Triceratops at the Los Angeles Natural History Museum

Most paleontologists accept that Tyrannosaurus was both an active predator and a scavenger like most large carnivores. By far the largest carnivore in its environment, T. rex was most likely an apex predator, preying upon hadrosaurs, armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. A study in 2012 by Karl Bates and Peter Falkingham found that Tyrannosaurus had the most powerful bite of any terrestrial animal that has ever lived, finding an adult Tyrannosaurus could have exerted 35,000 to 57,000 N (7,868 to 12,814 lbf) of force in the back teeth. Even higher estimates were made by Mason B. Meers in 2003. This allowed it to crush bones during repetitive biting and fully consume the carcasses of large dinosaurs. Stephan Lautenschlager and colleagues calculated that Tyrannosaurus was capable of a maximum jaw gape of around 80 degrees, a necessary adaptation for a wide range of jaw angles to power the creature's strong bite.

A debate exists, however, about whether Tyrannosaurus was primarily a predator or a pure scavenger. The debate originated in a 1917 study by Lambe which argued that large theropods were pure scavengers because Gorgosaurus teeth showed hardly any wear. This argument disregarded the fact that theropods replaced their teeth quite rapidly. Ever since the first discovery of Tyrannosaurus most scientists have speculated that it was a predator; like modern large predators it would readily scavenge or steal another predator's kill if it had the opportunity.

Paleontologist Jack Horner has been a major proponent of the view that Tyrannosaurus was not a predator at all but instead was exclusively a scavenger. He has put forward arguments in the popular literature to support the pure scavenger hypothesis:

Tyrannosaur arms are short when compared to other known predators. Horner argues that the arms were too short to make the necessary gripping force to hold on to prey. Other paleontologists such as Thomas Holtz Jr. argued that there are plenty of modern-day predators that do not use their forelimbs to hunt such as wolves, hyenas, and secretary birds as well as other extinct animals thought to be predators that would not have used their forelimbs such as phorusrhacids.

Tyrannosaurs had large olfactory bulbs and olfactory nerves (relative to their brain size). These suggest a highly developed sense of smell which could sniff out carcasses over great distances, as modern vultures do. Research on the olfactory bulbs of dinosaurs has shown that Tyrannosaurus had the most highly developed sense of smell of 21 sampled dinosaurs.

Tyrannosaur teeth could crush bone, and therefore could extract as much food (bone marrow) as possible from carcass remnants, usually the least nutritious parts. Karen Chin and colleagues have found bone fragments in coprolites (fossilized feces) that they attribute to tyrannosaurs, but point out that a tyrannosaur's teeth were not well adapted to systematically chewing bone like hyenas do to extract marrow.

Since at least some of Tyrannosaurus's potential prey could move quickly, evidence that it walked instead of ran could indicate that it was a scavenger. On the other hand, recent analyses suggest that Tyrannosaurus, while slower than large modern terrestrial predators, may well have been fast enough to prey on large hadrosaurs and ceratopsians.

Other evidence suggests hunting behavior in Tyrannosaurus. The eye sockets of tyrannosaurs are positioned so that the eyes would point forward, giving them binocular vision slightly better than that of modern hawks. It is not obvious why natural selection would have favored this long-term trend if tyrannosaurs had been pure scavengers, which would not have needed the advanced depth perception that stereoscopic vision provides. In modern animals, binocular vision is found mainly in predators.

A 2021 study focused on the vision and hearing of the small theropod , to which Tyrannosaurus was compared suggests that Tyrannosaurus was diurnal and would have hunted predominantly during daylight hours, a feature it shared with Dromaeosaurus, a third dinosaur compared to Shuvuuia in the study.

The damage to the tail vertebrae of this Edmontosaurus annectens skeleton (on display at the Denver Museum of Nature and Science) indicates that it may have been bitten by a Tyrannosaurus

A skeleton of the hadrosaurid Edmontosaurus annectens has been described from Montana with healed tyrannosaur-inflicted damage on its tail vertebrae. The fact that the damage seems to have healed suggests that the Edmontosaurus survived a tyrannosaur's attack on a living target, i.e. the tyrannosaur had attempted active predation. Despite the consensus that the tail bites were caused by Tyrannosaurus, there has been some evidence to show that they might have been created by other factors. For example, a 2014 study suggested that the tail injuries might have been due to Edmontosaurus individuals stepping on each other, while another study in 2020 backs up the hypothesis that biomechanical stress is the cause for the tail injuries. There is also evidence for an aggressive interaction between a Triceratops and a Tyrannosaurus in the form of partially healed tyrannosaur tooth marks on a Triceratops brow horn and squamosal (a bone of the neck frill); the bitten horn is also broken, with new bone growth after the break. It is not known what the exact nature of the interaction was, though: either animal could have been the aggressor. Since the Triceratops wounds healed, it is most likely that the Triceratops survived the encounter and managed to overcome the Tyrannosaurus. In a battle against a bull Triceratops, the Triceratops would likely defend itself by inflicting fatal wounds to the Tyrannosaurus using its sharp horns. Studies of Sue found a broken and healed fibula and tail vertebrae, scarred facial bones and a tooth from another Tyrannosaurus embedded in a neck vertebra, providing evidence for aggressive behavior. Studies on hadrosaur vertebrae from the Hell Creek Formation that were punctured by the teeth of what appears to be a late-stage juvenile Tyrannosaurus indicate that despite lacking the bone-crushing adaptations of the adults, young individuals were still capable of using the same bone-puncturing feeding technique as their adult counterparts.

Tyrannosaurus may have had infectious saliva used to kill its prey, as proposed by William Abler in 1992. Abler observed that the (tiny protuberances) on the cutting edges of the teeth are closely spaced, enclosing little chambers. These chambers might have trapped pieces of carcass with bacteria, giving Tyrannosaurus a deadly, infectious bite much like the Komodo dragon was thought to have. Jack Horner and Don Lessem, in a 1993 popular book, questioned Abler's hypothesis, arguing that Tyrannosaurus's tooth serrations as more like cubes in shape than the serrations on a Komodo monitor's teeth, which are rounded.

Tyrannosaurus, and most other theropods, probably primarily processed carcasses with lateral shakes of the head, like crocodilians. The head was not as maneuverable as the skulls of allosauroids, due to flat joints of the neck vertebrae.

Cannibalism

Evidence also strongly suggests that tyrannosaurs were at least occasionally cannibalistic. Tyrannosaurus itself has strong evidence pointing towards it having been cannibalistic in at least a scavenging capacity based on tooth marks on the foot bones, humerus, and metatarsals of one specimen. Fossils from the Fruitland Formation, Kirtland Formation (both Campanian in age) and the Maastrichtian aged Ojo Alamo Formation suggest that cannibalism was present in various tyrannosaurid genera of the San Juan Basin. The evidence gathered from the specimens suggests opportunistic feeding behavior in tyrannosaurids that cannibalized members of their own species. A study from Currie, Horner, Erickson and Longrich in 2010 has been put forward as evidence of cannibalism in the genus Tyrannosaurus. They studied some Tyrannosaurus specimens with tooth marks in the bones, attributable to the same genus. The tooth marks were identified in the humerus, foot bones and metatarsals, and this was seen as evidence for opportunistic scavenging, rather than wounds caused by intraspecific combat. In a fight, they proposed it would be difficult to reach down to bite in the feet of a rival, making it more likely that the bitemarks were made in a carcass. As the bitemarks were made in body parts with relatively scantly amounts of flesh, it is suggested that the Tyrannosaurus was feeding on a cadaver in which the more fleshy parts already had been consumed. They were also open to the possibility that other tyrannosaurids practiced cannibalism.

While there is no direct evidence of Tyrannosaurus raising their young (the rarity of juvenile and nest Tyrannosaur fossils has left researchers guessing), it has been suggested by some that like its closest living relatives, modern archosaurs (birds and crocodiles) Tyrannosaurus may have protected and fed its young. Crocodilians and birds are often suggested by some paleontologists to be modern analogues for dinosaur parenting. Direct evidence of parental behavior exists in other dinosaurs such as Maiasaura peeblesorum, the first dinosaur to have been discovered to raise its young, as well as more closely related Oviraptorids, the latter suggesting parental behavior in theropods.

In 2001, Bruce Rothschild and others published a study examining evidence for stress fractures and tendon avulsions in theropod dinosaurs and the implications for their behavior. Since stress fractures are caused by repeated trauma rather than singular events they are more likely to be caused by regular behavior than other types of injuries. Of the 81 Tyrannosaurus foot bones examined in the study, one was found to have a stress fracture, while none of the 10 hand bones were found to have stress fractures. The researchers found tendon avulsions only among Tyrannosaurus and Allosaurus. An avulsion injury left a divot on the humerus of Sue the T. rex, apparently located at the origin of the deltoid or teres major muscles. The presence of avulsion injuries being limited to the forelimb and shoulder in both Tyrannosaurus and Allosaurus suggests that theropods may have had a musculature more complex than and functionally different from those of birds. The researchers concluded that Sue's tendon avulsion was probably obtained from struggling prey. The presence of stress fractures and tendon avulsions, in general, provides evidence for a "very active" predation-based diet rather than obligate scavenging.

A 2009 study showed that smooth-edged holes in the skulls of several specimens might have been caused by Trichomonas-like parasites that commonly infect birds. According to the study, seriously infected individuals, including "Sue" and MOR 980 ("Peck's Rex"), might therefore have died from starvation after feeding became increasingly difficult. Previously, these holes had been explained by the bacterious bone infection Actinomycosis or by intraspecific attacks. A subsequent study found that while trichomoniasis has many attributes of the model proposed (osteolytic, intra oral) several features make the assumption that it was the cause of death less supportable by evidence. For example, the observed sharp margins with little reactive bone shown by the radiographs of Trichomonas-infected birds are dissimilar to the reactive bone seen in the affected T. rex specimens. Also, trichomoniasis can be very rapidly fatal in birds (14 days or less) albeit in its milder form, and this suggests that if a Trichomonas-like protozoan is the culprit, trichomoniasis was less acute in its non-avian dinosaur form during the Late Cretaceous. Finally, the relative size of this type of lesions is much larger in small bird throats, and may not have been enough to choke a T. rex. A more recent study examining the pathologies concluded that the osseous alteration observed most closely resembles those around healing human cranial trepanations and healing fractures in the Triassic reptile Stagonolepis, in the absence of infection. The possible cause may instead have been intraspecific combat.

One study of Tyrannosaurus specimens with tooth marks in the bones attributable to the same genus was presented as evidence of cannibalism. Tooth marks in the humerus, foot bones and metatarsals, may indicate opportunistic scavenging, rather than wounds caused by combat with another T. rex. Other tyrannosaurids may also have practiced cannibalism.

Paleoecology

Fauna of Hell Creek (Tyrannosaurus in dark red, left).

Tyrannosaurus lived during what is referred to as the Lancian faunal stage ( Maastrichtian age) at the end of the Late Cretaceous. Tyrannosaurus ranged from Canada in the north to at least New Mexico in the south of Laramidia. During this time Triceratops was the major herbivore in the northern portion of its range, while the titanosaurian sauropod Alamosaurus "dominated" its southern range. Tyrannosaurus remains have been discovered in different ecosystems, including inland and coastal subtropical, and semi-arid plains.

Tyrannosaurus and other animals of the Hell Creek Formation

Several notable Tyrannosaurus remains have been found in the Hell Creek Formation. During the Maastrichtian this area was subtropical, with a warm and humid climate. The flora consisted mostly of angiosperms, but also included trees like dawn redwood (Metasequoia) and . Tyrannosaurus shared this ecosystem with ceratopsians Leptoceratops, Torosaurus, and Triceratops, the hadrosaurid Edmontosaurus annectens, the parksosaurid Thescelosaurus, the ankylosaurs Ankylosaurus and Denversaurus, the pachycephalosaurs Pachycephalosaurus and Sphaerotholus, and the theropods Ornithomimus, Struthiomimus, Acheroraptor, Dakotaraptor, Pectinodon and .

Another formation with Tyrannosaurus remains is the Lance Formation of Wyoming. This has been interpreted as a bayou environment similar to today's Gulf Coast. The fauna was very similar to Hell Creek, but with Struthiomimus replacing its relative Ornithomimus. The small ceratopsian Leptoceratops also lived in the area.

In its southern range Tyrannosaurus lived alongside the titanosaur Alamosaurus, the ceratopsians Torosaurus, Bravoceratops and Ojoceratops, hadrosaurs which consisted of a species of Edmontosaurus, Kritosaurus and a possible species of Gryposaurus, the nodosaur Glyptodontopelta, the oviraptorid Ojoraptosaurus, possible species of the theropods and Richardoestesia, and the pterosaur Quetzalcoatlus. The region is thought to have been dominated by semi-arid inland plains, following the probable retreat of the Western Interior Seaway as global sea levels fell.

Tyrannosaurus may have also inhabited Mexico's Lomas Coloradas formation in Sonora. Though skeletal evidence is lacking, six shed and broken teeth from the fossil bed have been thoroughly compared with other theropod genera and appear to be identical to those of Tyrannosaurus. If true, the evidence indicates the range of Tyrannosaurus was possibly more extensive than previously believed. It is possible that tyrannosaurs were originally Asian species, migrating to North America before the end of the Cretaceous period.

Population estimates

According to studies published in 2021 by Charles Marshall et al., the total population of adult Tyrannosaurus at any given time was perhaps 20,000 individuals, with computer estimations also suggesting a total population no lower than 1,300 and no higher than 328,000. The authors themselves suggest that the estimate of 20,000 individuals is probably lower than what should be expected, especially when factoring in that disease pandemics could easily wipe out such a small population. Over the span of the genus' existence, it is estimated that there were about 127,000 generations and that this added up to a total of roughly 2.5 billion animals until their extinction.

In the same paper, it is suggested that in a population of Tyrannosaurus adults numbering 20,000, the number of individuals living in an area the size of California could be as high as 3,800 animals, while an area the size of Washington D.C. could support a population of only two adult Tyrannosaurus. The study does not take into account the number of juvenile animals in the genus present in this population estimate due to their occupation of a different niche than the adults, and thus it is likely the total population was much higher when accounting for this factor. Simultaneously, studies of living carnivores suggest that some predator populations are higher in density than others of similar weight (such as jaguars and hyenas, which are similar in weight but have vastly differing population densities). Lastly, the study suggests that in most cases, only one in 80 million Tyrannosaurus would become fossilized, while the chances were likely as high as one in every 16,000 of an individual becoming fossilized in areas that had more dense populations.

Meiri (2022) questioned the reliability of the estimates, citing uncertainty in metabolic rate, body size, sex and age-specific survival rates, habitat requirements and range size variability as shortcomings Marshall et al. did not take into account. The authors of the original publication replied that while they agree that their reported uncertainties were probably too small, their framework is flexible enough to accommodate uncerainty in physiology, and that their calculations do not depend on short-term changes in population density and geographic range, but rather on their long-term averages. Finally, they remark that they did estimate the range of reasonable survivorship curves and that they did include uncertainty in the time of onset of sexual maturity and in the growth curve by incorporating the uncertainty in the maximum body mass.

Cultural significance

Since it was first described in 1905, T. rex has become the most widely recognized dinosaur species in popular culture. It is the only dinosaur that is commonly known to the general public by its full scientific name ( binomial name) and the scientific abbreviation T. rex has also come into wide usage. Robert T. Bakker notes this in The Dinosaur Heresies and explains that, "a name like ' T. rex' is just irresistible to the tongue."

Explanatory notes

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71. ^ Smith, S.D; Persons, W.S.; Xing, Lida (2016). "A tyrannosaur trackway at Glenrock, Lance Formation (Maastrichtian), Wyoming". Cretaceous Research. 61: 1-4. Bibcode:2016CrRes..61....1S. doi:10.1016/j.cretres.2015.12.020.

72. "T. Rex brain study reveals a refined 'nose'". Calgary Herald. October 28, 2008.

73. ^ Benoit, Florian Bouabdellah, Emily Lessner, and Julien (January 20, 2022). "The rostral neurovascular system of Tyrannosaurus rex". Palaeontologia Electronica. 25 (1): 1-20. doi:10.26879/1178. ISSN 1094-8074. S2CID 246204236.

74. ^ Hurlburt, G. S.; Ridgely, R. C.; Witmer, L. M. (July 5, 2013). "Relative size of brain and cerebrum in Tyrannosaurid dinosaurs: an analysis using brain-endocast quantitative relationships in extant alligators". In Parrish, M. J.; Molnar, R. E.; Currie, P. J.; Koppelhus, E. B. (eds.). Tyrannosaurid Paleobiology. Indiana University Press. pp. 134-154. ISBN 978-0-253-00947-0.

75. ^ Brusatten, Steve (2018). The Rise and Fall of the Dinosaurs. New York, New York: HarperCollins Publishers. p. 219. ISBN 978-0-06-249043-8.

76. ^ Collins, N. (June 22, 2011). "Tyrannosaurus Rex 'hunted in packs'". The Telegraph. Archived from the original on January 10, 2022.

77. ^ Currie, Philip J. (1998). "Possible evidence of gregarious behaviour in tyrannosaurids" (PDF). Gaia. 15: 271-277. Archived from the original (PDF) on March 26, 2009. (not printed until 2000)

78. ^ "Time to Slay the T. rex Scavenger "Debate"". National Geographic. July 16, 2013. Archived from the original on July 12, 2018.

79. ^ Black, Riley (April 13, 2012). "When Tyrannosaurus Chomped Sauropods". Smithsonian Magazine. Smithsonian Media. 25: 469. doi:10.1671/0272-4634(2005)025[0469:TRFTUC]2.0.CO;2. S2CID 131583311.

80. ^ Black, Riley (2012). "The Tyrannosaurus rexs Dangerous and Deadly Bite". Smithsonian Magazine. Smithsonian Institution.

81. ^ Scully, C. (2002). Oxford Handbook of Applied Dental Sciences. Oxford University Press. p. 156. ISBN 978-0-19-851096-3.

82. ^ Lambe, L. B. (1917). "The Cretaceous theropodous dinosaur Gorgosaurus". Memoirs of the Geological Survey of Canada. 100: 1-84. doi:10.4095/101672.

83. ^ Farlow, J. O.; Holtz (2002). "The fossil record of predation in dinosaurs" (PDF). In Kowalewski, M.; Kelley, P. H. (eds.). The Fossil Record of Predation. The Paleontological Society Papers. Vol. 8. T. R. Jr. pp. 251-266. Archived from the original (PDF) on October 31, 2008.

84. Horner, J. R. (1994). "Steak knives, beady eyes, and tiny little arms (a portrait of Tyrannosaurus as a scavenger)". The Paleontological Society Special Publication. 7: 157-164. doi:10.1017/S2475262200009497.

85. ^ Farlow, J. O.; Holtz, T.R. (2002). Kowalewski, M.; Kelley, P. H. (eds.). "The Fossil Record of Predation in Dinosaurs" (PDF). The Paleontological Society Papers. 8: 251-266. doi:10.1017/S108933260000111X. Archived from the original (PDF) on October 31, 2008.

86. ^ Holtz, Thomas R. (2008). "Chapter 20: A critical re-appraisal of the obligate scavenging hypothesis for Tyrannosaurus rex and other tyrant dinosaurs". In Larson, Peter; Carpenter, Kenneth (eds.). Tyrannosaurus rex: The Tyrant King. Book Publishers. pp. 371-394. ISBN 978-0-253-35087-9.

87. ^ Carpenter, K. (1998). "Evidence of predatory behavior by theropod dinosaurs". Gaia. 15: 135-144. Archived from the original on November 17, 2007.

88. ^ Eberth, David A.; Evans, David C., eds. (2015). "Paleopathology in Late Cretaceous Hadrosauridae from Alberta, Canada". Hadrosaurs. Indiana University Press. pp. 540-571. ISBN 978-0-253-01390-3. preprint

89. ^ Happ, J.; Carpenter, K. (2008). "An analysis of predator-prey behavior in a head-to-head encounter between Tyrannosaurus rex and Triceratops". In Carpenter, K.; Larson, P. E. (eds.). Tyrannosaurus rex, the Tyrant King (Life of the Past). Bloomington: Indiana University Press. pp. 355-368. ISBN 978-0-253-35087-9.

90. ^ Dodson, P. (1996). The Horned Dinosaurs. Princeton University Press. p. 19.

91. ^ Tanke, D. H.; Currie, P. J. (1998). "Head-biting behavior in theropod dinosaurs: paleopathological evidence" (PDF). Gaia (15): 167-184. ISSN 0871-5424. Archived from the original (PDF) on February 27, 2008.

92. ^ Peterson, J. E.; Daus, K. N. (March 4, 2019). "Feeding traces attributable to juvenile Tyrannosaurus rex offer insight into ontogenetic dietary trends". PeerJ. 7: e6573. doi:10.7717/peerj.6573. ISSN 2167-8359. PMC 6404657. PMID 30863686.

93. ^ Goldstein, E. J. C.; Tyrrell, K. L.; Citron, D. M.; Cox, C. R.; Recchio, I. M.; Okimoto, B.; Bryja, J.; Fry, B. G. (June 1, 2013). "Anaerobic and aerobic bacteriology of the saliva and gingiva from 16 captive Komodo dragons (Varanus komodoensis): new implications for the "bacteria as venom" model". Journal of Zoo and Wildlife Medicine. 44 (2): 262-272. doi:10.1638/2012-0022R.1. ISSN 1042-7260. PMID 23805543. S2CID 9932073.

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97. ^ ""The Best of all Mothers" Maiasaura peeblesorum". bioweb.uwlax.edu/. University of Wisconsin-La Crosse.

98. ^ Rothschild, B.; Tanke, D. H.; Ford, T. L. (2001). "Theropod stress fractures and tendon avulsions as a clue to activity". In Tanke, D. H.; Carpenter, K. (eds.). Mesozoic Vertebrate Life. Indiana University Press. pp. 331-336.

99. ^ Rega, E. (2012). "Disease in Dinosaurs". In Brett-Surman, M.; Holtz, T.; Farlow, J. (eds.). The Complete Dinosaur. Bloomington: Indiana University Press.

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101. ^ Weishampel, D. B.; Barrett, P. M.; Coria, R. A.; Loeuff, J. L.; Xu, X.; Zhao, X.; Sahni, A.; Gomani, E. M. P.; Noto, C. R. (2004). "Dinosaur Distribution". In Weishampel, D. B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 574-588. ISBN 978-0-520-24209-8.

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103. Chang, Kenneth (April 15, 2021). "How Many Tyrannosaurus Rexes Ever Lived on Earth? Here's a New Clue". The New York Times. Archived from the original on December 28, 2021.

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105. ^ Marshall, Charles R.; Latorre, Daniel V.; Wilson, Connor J.; Frank, Tanner M.; Magoulick, Katherine M.; Zimmt, Joshua P.; Poust, Ashley W. (2022). "With what precision can the population size of Tyrannosaurus rex be estimated? A reply to Meiri". Frontiers of Biogeography. 14 (2). doi:10.21425/F5FBG55042. S2CID 245314491. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.

Further reading

External links

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Tyrannosaurus is a genus of large theropod dinosaur. The species Tyrannosaurus rex ( rex meaning "king" in Latin), often called T. rex or colloquially T-Rex , is one of the best represented theropods. It lived throughout what is now western North America, on what was then an island continent known as Laramidia.

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Option 1:

"Physical activities and sports systems shape individual development and social connections."

Primary Concepts: Function, Form, Connection

This version emphasizes how sports work as systems (Form) and their impact on both personal and social levels (Function)

Lines of Inquiry could explore:

The organisation and structure of different sports

Ways sports influence personal development

How sports create community connections

Option 2:

"Choices and engagement in physical activities reflect and transform personal and community wellbeing."

Primary Concepts: Causation, Change, Responsibility

This version focuses on the relationship between choices and outcomes

Lines of Inquiry could explore:

Factors influencing sports participation

Impact of physical activity on wellbeing

Ways to promote active engagement in communities

Option 3:

"The evolution of sports and physical activities influences human behaviour and social interactions."

Primary Concepts: Form, Function, Change

This version combines your stronger concepts with the element of change

Lines of Inquiry could explore:

How sports have developed over time

The role of sports in modern society

Ways sports shape human behaviour and relationships

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GeoPard - Precision agriculture Mapping software

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Disadvantages and benefits of monocrop agriculture

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Are you hearing about monocropping for the first time? Monocrop agriculture is about sowing one crop every year in a similar piece of land, and not choosing to

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Analysis of Lines of Inquiry:

"What is Mental Health" → explores definition, components, and characteristics

"What issues do Primary School learners face that affect their mental health" → examines challenges, influences, and impacts

"What can we do to support Primary School Learners mental health" → investigates responsibility, action, and support systems

Key Concepts emerging from these lines:

Well-being

Balance

Connection

Responsibility

Support

Change

Influence

Conceptual Relationships:

Well-being connects to multiple factors in a child's life

Support systems influence mental health outcomes

Individual and collective actions impact emotional well-being

Balance relates to mental health management

Based on this analysis, here are some possible central ideas (from broad to more specific):

"Mental health is a dynamic state of well-being that requires understanding, support, and balanced actions from individuals and communities."

"Understanding and supporting mental health in primary school creates foundations for lifelong emotional well-being."

"Mental health is influenced by various factors and can be supported through understanding, awareness, and collaborative action."

I recommend the first option because it:

Encompasses all three lines of inquiry

Highlights both individual and collective responsibility

Addresses the dynamic nature of mental health

Is age-appropriate for primary students

Promotes both understanding and action

Allows for exploration of support systems and personal strategies

Emphasizes the importance of balance

This central idea can be supported by these conceptual understandings:

Mental health is an essential component of overall well-being

Various factors influence mental health in different ways

Everyone has a role in creating supportive environments

Understanding mental health helps us take better care of ourselves and others

To ensure age-appropriateness and sensitivity, this central idea can be explored through:

Personal connections

Safe and supportive discussions

Age-appropriate examples

Positive focus on well-being

Emphasis on support systems

Developmentally appropriate strategies

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how school affects our mental health! (NO PRESSURE. :))

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how school affects our mental health! (NO PRESSURE. :))

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thanks for understanding (PYPX)

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Mountain Heights Academy | Utah Online Public School Grade 7-12 - How School Affects Mental Health: Understanding the Impact on Students

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Explore how school impacts student mental health, focusing on academic pressure, social challenges, and coping strategies for better well-being.

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Endangered Animals Central Idea Development

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Endangered Animals Central Idea Development

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Option 1:

"Human actions and environmental changes impact species survival and ecosystem balance."

Primary Concepts: Causation, Change, Responsibility

This version emphasizes the relationship between human activities and environmental consequences

Lines of Inquiry could explore:

Causes of species endangerment

Impact of environmental changes on ecosystems

Human responsibility in species conservation

Option 2:

"Different perspectives and understanding of endangered species influence conservation efforts and outcomes."

Primary Concepts: Perspective, Causation, Responsibility

This version focuses on how viewpoints affect action and change

Lines of Inquiry could explore:

Various perspectives on wildlife conservation

Factors influencing conservation success

Ways to promote environmental awareness

Option 3:

"The interconnectedness between human choices and biodiversity shapes environmental sustainability."

Primary Concepts: Connection, Causation, Form

This version emphasizes the systemic nature of environmental challenges

Lines of Inquiry could explore:

Relationships within ecosystems

Human impact on natural habitats

Solutions for environmental preservation

Key Conceptual Understandings these support:

Human actions have direct and indirect consequences on wildlife

Different perspectives influence conservation efforts

Environmental changes affect multiple species and systems

Conservation requires understanding of interconnections

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Analysis of Lines of Inquiry:

"What is the circular economy and how does it work" → explores systems, structure, and processes

"How will the circular economy influence the economy" → focuses on change, impact, and interconnection

"What actions can people take to improve the circular economy" → investigates responsibility, action, and transformation

Key Concepts emerging from these lines:

Systems

Change

Responsibility

Interconnection

Sustainability

Impact

Conceptual Relationships:

Systems influence behavior and outcomes

Individual actions contribute to systemic change

Economic models affect environmental and social systems

Sustainability connects to economic decisions

Based on this analysis, here are some possible central ideas (from broad to more specific):

"The circular economy represents a transformative system where responsible choices and actions create sustainable patterns of production and consumption."

"A circular economy challenges traditional economic models by reimagining how resources flow through systems to create sustainable value and reduce waste."

"The transition to a circular economy requires systematic change and individual action to create sustainable economic patterns."

I recommend the second option because it:

Addresses all three lines of inquiry comprehensively

Incorporates key concepts (systems, change, sustainability)

Highlights both the systemic nature and the transformative aspect

Allows for exploration of personal responsibility while maintaining focus on the bigger picture

Promotes critical thinking about economic models

Enables investigation of both macro and micro levels of the circular economy

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Summary

how does my mental health affect my physical health

what can I do to help myself

Physical health problems significantly increase our risk of developing mental health problems, and vice versa.

Nearly one in three people with a long-term physical health condition also has a mental health problem, most often depression or anxiety.

How does my mental health affect my physical health?

Research shows that people with a mental health problem are more likely to have a preventable physical health condition such as heart disease.

This can be for a variety of reasons, including:

genetics - the genes that make it more likely that you will develop a mental health problem may also play a part in physical health problems

low motivation - some mental health problems or medications can affect your energy or motivation to take care of yourself

difficulty with concentration and planning - you may find it hard to arrange or attend medical appointments if your mental health problem affects your concentration

lack of support to change unhealthy behaviour - healthcare professionals may assume you're not capable of making changes, so won't offer any support to cut down on drinking or give up smoking, for example

being less likely to receive medical help - healthcare professionals may assume your physical symptoms are part of your mental illness and not investigate them further. People with a mental illness are less likely to receive routine checks (like blood pressure, weight and cholesterol) that might detect symptoms of physical health conditions earlier.

As well as this, mental health problems can come with physical symptoms. Our bodies and minds are not separate, so it's not surprising that mental ill health can affect your body. Depression can come with headaches, fatigue and digestive problems, and anxiety can create an upset stomach, for example. Other symptoms can include insomnia, restlessness and difficulty concentrating.

What can I do to help myself?

Having a mental health problem doesn't mean it's inevitable that you will develop a physical health problem. There are things you can do to give yourself the best chance of staying physically well.

Exercise

Physical activity is a great way to keep you physically healthy as well as improving your mental wellbeing. Research shows that doing exercise releases feel-good chemicals called endorphins in the brain. Even a short burst of 10 minutes brisk walking can improve your mental alertness, energy and mood.

Whether you're tending your garden or running a marathon, exercise can significantly improve your quality of life. Finding an activity you enjoy can make you feel less stressed, more focused, and give you a sense of purpose. For more tips on ways to get started, read our guide on how to look after your mental health using exercise.

Eat well

Eating well can improve your wellbeing and your mood. A balanced diet is one that includes healthy amounts of proteins, essential fats, complex carbohydrates, vitamins, minerals and water. The food we eat can influence the development, management and prevention of numerous mental health conditions including depression and dementia.

Stop smoking

Smoking has a negative impact on both mental and physical health. Many people with mental health problems believe that smoking relieves their symptoms, but these effects are only short-term. It's never too late to quit, and there is now a lot of support available to help you give up.

Make an appointment with your GP

If you're worried about your physical health, or you've been invited for a routine check or screening, make an appointment to see your GP. Waiting times will be different at different GP surgeries: ask for an emergency appointment if you need to see someone urgently.

If you find it hard to talk to healthcare professionals or are worried you won't be listened to, you could bring someone to help you assert yourself. This could be a friend, relative or professional advocate. Mind has more information on finding an advocate.

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How your mental health affects your physical health, and what you can do to help yourself.

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The Impact of School on Mental Health: Understanding its Importance for Students and the Effects of Bullying

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The school environment can have a profound impact on the mental well-being of students. Various factors including academic pressure, social dynamics, and school stressors can influence and sometimes…

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Let me analyze these lines of inquiry to generate a meaningful central idea about the KT-Boundary and evolutionary change.

Analysis of Lines of Inquiry:

1. "What is the KT-Boundary" → explores evidence, time periods, and geological markers

2. "What does the KT-Boundary tell us about extinction" → examines causation, change, and patterns

3. "How did the extinction give rise to mammals especially humans" → investigates adaptation, evolution, and opportunity

Key Concepts emerging from these lines:

- Change

- Causation

- Evidence

- Patterns

- Evolution

- Transformation

- Opportunity

Conceptual Relationships:

- Major events create conditions for evolutionary change

- Evidence helps us understand past transformations

- Extinction and adaptation are interconnected processes

- Environmental changes influence species development

Based on this analysis, here are some possible central ideas (from broad to more specific):

1. "Catastrophic events in Earth's history create opportunities for evolutionary transformation, as evidenced by the rise of mammals after the KT extinction event."

2. "The KT-Boundary represents how dramatic environmental changes can lead to both extinction and evolutionary innovation."

3. "Evidence from Earth's past reveals how extinction events can create opportunities for new species to evolve and thrive."

I recommend the first option because it:

- Encompasses all three lines of inquiry

- Connects cause and effect across geological time

- Highlights both destruction and creation

- Links past events to present life forms

- Promotes understanding of evolutionary processes

- Encourages evidence-based thinking

- Allows exploration of multiple scientific concepts

This central idea can be supported by these conceptual understandings:

1. Geological evidence tells stories of Earth's major transformations

2. Mass extinctions can create opportunities for surviving species

3. Environmental changes drive evolutionary adaptation

4. Scientific evidence helps us reconstruct past events and their consequences

To support investigation, consider these aspects:

- Geological time scales

- Fossil evidence

- Environmental changes

- Survival adaptations

- Evolutionary processes

- Scientific methodology

- Species diversity

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Analysis of Lines of Inquiry:

1. "What is Ocean Pollution" → explores forms, impact, and characteristics

2. "What causes ocean pollution?" → examines responsibility, causation, and human impact

3. "What can we do to help our oceans?" → investigates action, change, and solutions

Key Concepts emerging from these lines:

- Responsibility

- Impact

- Change

- Connection

- Action

- Sustainability

- Causation

Conceptual Relationships:

- Human actions directly impact ocean health

- Individual and collective choices affect marine ecosystems

- Solutions require understanding of causes and effects

- Environmental systems are interconnected

Based on this analysis, here are some possible central ideas (from broad to more specific):

1. "Human choices and actions impact ocean health, requiring understanding and responsible solutions to create positive change."

2. "The health of our oceans reflects human interactions with marine environments and requires collective action for preservation."

3. "Ocean pollution is a consequence of human activities that demands understanding and responsible action for positive change."

I recommend the first option because it:

- Addresses all three lines of inquiry

- Emphasizes both individual and collective responsibility

- Highlights the relationship between understanding and action

- Promotes solution-oriented thinking

- Encourages personal connection to the issue

- Allows for exploration of multiple types of pollution

- Emphasizes the power of choice and change

This central idea can be supported by these conceptual understandings:

1. Ocean pollution takes many forms and affects marine life in different ways

2. Human activities on land and sea contribute to ocean pollution

3. Individual and collective actions can help protect ocean environments

4. Healthy oceans are essential for planetary well-being

Key aspects for investigation:

- Types of ocean pollution

- Sources of pollution

- Impact on marine life

- Global consequences

- Personal connections

- Solution strategies

- Conservation efforts

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Option 1:

"Music's structure and expression shape human experiences and emotional connections across cultures."

Primary Concepts: Form, Function, Connection

This version integrates musical structure with its emotional impact

Lines of Inquiry could explore:

The fundamental elements of musical composition

How music influences emotional wellbeing

Ways music connects people across cultures

Option 2:

"The evolution of musical forms and functions reflects and influences human development and society."

Primary Concepts: Change, Form, Function

This version emphasizes the developmental nature of music

Lines of Inquiry could explore:

How musical forms have evolved over time

Ways technology has transformed music creation

Impact of music on social and emotional wellbeing

Option 3:

"Musical expression serves as a universal language that transforms personal and cultural experiences."

Primary Concepts: Function, Change, Connection

This version focuses on music's role in human experience

Lines of Inquiry could explore:

How music communicates across boundaries

The relationship between music and emotional wellness

Ways musical expression shapes cultural identity

Key Conceptual Understandings these support:

Music has both technical structure and emotional purpose

Musical expression evolves with technological and cultural changes

Music serves multiple functions in human society

Musical forms influence emotional and social connections

Each central idea allows for exploration of:

Technical aspects (music theory, composition)

Emotional impacts (wellbeing, therapy)

Cultural significance (evolution, social connection)

Technological development (changes in creation/production)

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Let me analyze these lines of inquiry to generate a meaningful central idea about climate change.

Analysis of Lines of Inquiry:

1. "What is Climate Change" → explores patterns, systems, and evidence

2. "What causes climate change" → examines causation, responsibility, and human impact

3. "What can we do to raise awareness about climate change?" → investigates action, communication, and advocacy

Key Concepts emerging from these lines:

- Change

- Causation

- Responsibility

- Communication

- Impact

- Action

- Advocacy

Conceptual Relationships:

- Human activities influence global climate systems

- Understanding leads to informed action

- Individual and collective choices affect climate patterns

- Communication drives awareness and change

Based on this analysis, here are some possible central ideas (from broad to more specific):

1. "Understanding climate change and its causes empowers individuals to become advocates for environmental action."

2. "Climate change is a consequence of human activities that requires understanding and communication to inspire global action."

3. "The impact of climate change on Earth's systems demands informed advocacy and collective responsibility."

I recommend the first option because it:

- Addresses all three lines of inquiry comprehensively

- Emphasizes the relationship between understanding and action

- Promotes student agency and empowerment

- Links knowledge to advocacy

- Encourages both personal and collective responsibility

- Allows for exploration of scientific evidence

- Supports development of communication skills

This central idea can be supported by these conceptual understandings:

1. Climate change affects Earth's systems in interconnected ways

2. Human activities contribute to changes in global climate patterns

3. Effective communication of climate science can inspire action

4. Individual and collective advocacy can lead to positive change

Key aspects for investigation:

- Climate science basics

- Evidence of change

- Human impacts

- Natural vs. anthropogenic changes

- Communication strategies

- Action initiatives

- Advocacy skills