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For polar bears, profound obesity is a benign state.

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For polar bears, profound obesity is a benign state.

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Polar bear shave adapted genetically to a high fat diet that many people now impose on themselves. Polar bears eat a lot of fish and then they get fat and do not leave fat, because they need it for adaptation in the Arctic.
The bear's stark white coat provides camouflage in surrounding snow and ice. But under their fur, polar bears have black skin—the better to soak in the sun's warming rays.
https://www.nationalgeographic.com/animals/mammals/facts/polar-bear

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The trait that was selected was the roar of the lion. They roar is helping them advertise territorial boundaries. This is an advantage for them because the stronger and louder the roar is the more protected the lions are. They drive other lions away in order to keep the territory for them. They would have more food because the others will be scared of him.

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Extreme adaptations to their lives in the high arctic made polar bears have several new genes that supports its everyday life in the cold areas. This includes: fatty acid metabolism and cardio vascular functions. These help support the polar bears high fat diet, while avoiding fatty plaques in their arteries so that the animal doesn't develop a cardiovascular disease.
Before you continue to Google Search

"Before You Continue To Google Search". Google.Com, 2023, https://www.google.com/search?q=polar+bears&oq=polar+bears&aqs=chrome.0.0i271j46i512j0i512l2j46i199i465i512j46i512j0i512l4.3545j0j7&sourceid=chrome&ie=UTF-8#imgrc=F6CRpmGurGlKwM. Accessed 30 Jan 2023.

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Lions have many different types of roars however the loud or more correlated ones are advantageous. The lions with loud and aggressive roars can mark their territories and make other lions stay away from them. They can create a safe space around them which effects their survival and life quality. Due to their power and roar they can mate much easily since they attract females more because they can protect them and their offsprings. These lions mate much more frequently which then impacts their reproduction and their genes are passed on many times.

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The trait that was selected for pitcher plants was carnivorousness.
The trait is important and beneficial because Carnivorous pitcher plants capture insect prey to acquire essential nutrients while growing on extremely poor soils. A few individual species have evolved mutualistic relationships with small mammals that visit the traps to harvest nectar and leave fecal droppings in the pitchers.

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-The trait the plants developed was their carnivorousness and ability to digest insects for protein.
- These plants developed this feature since they lived in low protein environments and did not have enough nutrition without this ability
- the proteins that were used to fight disease developed into the enzymes that they use for digestion.
- they have two ways of collecting nutrients, one is through photosynthesis, and the other is through digesting insects.
- Having these two methods is advantageous and helpful for their survival since they have mlutliple sources of protein and energy. This advantage helps them survive as well as raising the chance of reproduction and the passing of genes to their offspring.

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This article talks about how it was discovered that when starfish' body temperature heat up above 35C they die. They have also discovered how they tend to lose their legs once they heat up above 31C. In order for them to survive, they are able to direct all the heat into one arm (use their arm as heat sink) so they only lose one arm rather than their life. Marine biologists have found out that this might occur due to too warm environmental conditions for the starfish. Since starfish are cold-blooded animals, they cannot adapt well to their surrounding environment and because of that, they are the vulnerable due to the weather conditions.

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-Does the volume of the roar determine the masculinity of the lion
-Female lions can be identified by having a lighter roar
-The roar says very little about the lion
-The looks of a lion doesn't affect their roar

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-The trait that was selected was carnivorousness
-As a means of producing their own "fertiliser," the plants evolved into flesh-eaters.
-This demonstrated that plant proteins that were previously used to fight disease and stress had evolved into the digestive enzymes that break down the insects' bodies over time.

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Polar bears eat a high-fat diet, since the animals they have access too carry large amounts of fat. This trait developed becasue only preys with high-fat are accessable for the bears. Since individuals who could process the large amounts what warmer and less hungry, it had an advantage and survived. This variation was an adaptation that happened quickly, and was inheritable.

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Lions have a roar, and having a good roar makes them advantageous over  other lions. They defend themselves and attack better when they have a roar. They are also probably more attractive towards the female lions. Therefore, these lions reproduce more easily, and their genes get passed down and they developed to have better roars

https://www.smithsonianmag.com/science-nature/the-truth-about-lions-11558237/

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Scenario 4: Can you Judge a Lion by his roar? 

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Scenario 4: Can you Judge a Lion by his roar? 

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Link to article: https://www.theatlantic.com/technology/archive/2012/08/can-you-judge-a-lion-by-his-roar-sadly-no/261616/

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Can You Judge a Lion By His Roar? Sadly, No

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A lion’s roar doesn’t tell you much about whether an animal is a king of the jungle, or a joker.

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Scenario 1: Monarch Butterflies Weaponize Milkweed Toxins

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Scenario 1: Monarch Butterflies Weaponize Milkweed Toxins

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Link to article: https://www.scientificamerican.com/article/how-monarch-butterflies-evolved-to-eat-a-poisonous-plant/

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FLICKR, USFWS MIDWEST Monarch butterfly caterpillars have evolved the ability to store toxins known as cardenolides, obtained from their milkweed diet, specifically to make themselves poisonous to birds, as has at least one other species of milkweed-munching caterpillar, according to a study published Wednesday (November 4) in Proceedings of the Royal Society B.

"This finding is fascinating and novel," Stephen Malcolm, a professor at Western Michigan University who studies cardenolides but was not involved in the new research, wrote in an email to The Scientist. "It is exciting to have evidence for the importance of top-down influences from predators."

Scientists have long known that milkweed cardenolides, which in most animals disable a vital sodium-potassium pump enzyme if they are absorbed into the blood, serve to make caterpillars and butterflies dangerous meals for their predators, but whether that acquired toxicity was a side...

Monarchs ( Danaus plexippus) have specially adapted enzymes that are almost entirely immune to cardenolides' toxic effects, as do queen butterflies ( Danaus gilippus), although the queens' enzymes are more susceptible to the compounds than monarchs'. The enzymes of common crow butterflies ( Euploea core) can be disabled by cardenolides, but this species does not absorb the toxins into its bloodstream, instead breaking them down or simply excreting them before they can do any harm. Agrawal and his team hypothesized that if cardenolide-resistant enzymes arose simply to help caterpillars eat milkweed, then monarchs and queens would eat more milkweed than common crows. But all three species chowed down equally.

"These little caterpillars are plowing through [the milkweed]," Agrawal said. "They basically all do really well," regardless of whether they have the enzyme adaptation or not.

If the cardenolide-resistant enzymes don't help the caterpillars eat more milkweed, Agrawal and Petschenka reasoned, they must exist for another reason, such as predator defense. The researchers measured levels of cardenolides in the bodies of the three caterpillar species and found that, while common crows don't store any, both monarchs and queens store the toxic compounds, with monarchs storing concentrations about twice as high as queens. Such storage turns these species into poisonous prey, effectively warding off birds and other predators.

"I would call it a landmark paper," said Michael Singer, a professor at Wesleyan University who studies similar systems but was not involved in this study. "[It helped] distinguish between these alternative views" of how and why insects develop resistance to toxins. While the experiments weren't especially complicated, he added, they were "experiments that people hadn't thought to try . . . and they turned out to be very revealing."

Other researchers in the field were also impressed. "[It's] an important finding," Brian Farrell, a professor at Harvard who studies insect evolution and was not involved in the research, wrote in an email to The Scientist. "[It's] a very useful case study for pedagogy as well as further research on similar systems."

Agrawal pointed out that many other insect species have also evolved to feed on milkweed, with similar or identical adaptations to those that monarch and queen butterflies have. He plans to look at these species in future studies to determine if they, too, are using the toxins to protect themselves from predators.

Singer is also curious. "Now I'd like to know how general this really is," he said.

G. Petschenka and A.A. Agrawal, "Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet," Proceedings of the Royal Society B, doi:10.1098/rspb.2015.1865, 2015.

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FLICKR, USFWS MIDWEST Monarch butterfly caterpillars have evolved the ability to store toxins known as cardenolides, obtained from their milkweed diet, specifically to make themselves poisonous to birds, as has at least one other species of milkweed-munching caterpillar, according to a study published Wednesday (November 4) in Proceedings of the Royal Society B .

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Scenario 2: Polar bear genome gives new insight into adaptations to high-fat diet

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Scenario 2: Polar bear genome gives new insight into adaptations to high-fat diet

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Link to article: http://news.berkeley.edu/2014/05/08/polar-bear-genome-gives-new-insight-into-adaptations-to-high-fat-diet/

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A comparison of the genomes of polar bears and brown bears reveals that the polar bear is a much younger species than previously believed, having diverged from brown bears less than 500,000 years ago.

The analysis also uncovered several genes that may be involved in the polar bears' extreme adaptations to life in the high Arctic. The species lives much of its life on sea ice, where it subsists on a blubber-rich diet of primarily marine mammals.

The genes pinpointed by the study are related to fatty acid metabolism and cardiovascular function, and may explain the bear's ability to cope with a high-fat diet while avoiding fatty plaques in their arteries and the cardiovascular diseases that afflict humans with diets rich in fat. These genes may provide insight into how to protect humans from the ill effects of a high-fat diet.

The study was a collaboration between Danish researchers, led by Eske Willerslev and including Rune Dietz, Christian Sonne and Erik W. Born, who provided polar bear blood and tissue samples; and researchers at BGI in China, including Shiping Liu, Guojie Zhang and Jun Wang, who sequenced the genomes and analyzed the data together with a team of UC Berkeley researchers, including Eline Lorenzen, Matteo Fumagalli and Rasmus Nielsen. Nielsen is a UC Berkeley professor of integrative biology and of statistics.

"For polar bears, profound obesity is a benign state," said Lorenzen, one of the lead authors and a UC Berkeley postdoctoral fellow. "We wanted to understand how they are able to cope with that."

"The promise of comparative genomics is that we learn how other organisms deal with conditions that we also are exposed to," said Nielsen, a member of UC Berkeley's Center for Theoretical Evolutionary Genomics. "For example, polar bears have adapted genetically to a high fat diet that many people now impose on themselves. If we learn a bit about the genes that allows them to deal with that, perhaps that will give us tools to modulate human physiology down the line."

The findings accompany the publication of the first assembled genome of the polar bear as the cover story in the May 8 issue of the journal Cell.
Close cousins
The genome analysis comes at a time when the polar bear population worldwide, estimated at between 20,000 and 25,000, is declining and its habitat, Arctic sea ice, is rapidly disappearing. As the northern latitudes warm, the polar bear's distant cousin, the brown or grizzly bear ( Ursus arctos), is moving farther north and occasionally interbreeding with the polar bear ( Ursus maritimus) to produce hybrids dubbed pizzlies.

Their ability to interbreed is a result of this very close relationship, Nielsen said, which is one-tenth the evolutionary distance between chimpanzees and humans. Previous estimates of the divergence time between polar bears and brown bears ranged from 600,000 to 5 million years ago.

"It's really surprising that the divergence time is so short. All the unique adaptations polar bears have to the arctic environment must have evolved in a very short amount of time," he said. These adaptations include not only a change from brown to white fur and development of a sleeker body, but big physiological and metabolic changes as well. "There has been a lot of debate about it, but I think we really nailed down what the divergence time is between them, and it is surprisingly recent."

Genetic changes affect fat metabolism

The genome comparison reveals that over several hundred thousand years, natural selection drove major changes in genes related to fat transport in the blood and fatty acid metabolism. One of the most strongly selected genes is APOB, which in mammals encodes the main protein in LDL (low density lipoprotein), known widely as "bad" cholesterol. Changes or mutations in this gene reflect the critical nature of fat in the polar bear diet and the animal's need to deal with high blood levels of glucose and triglycerides, in particular cholesterol, which would be dangerous in humans. Fat comprises up to half the weight of a polar bear.

"The life of a polar bear revolves around fat," Lorenzen said. "Nursing cubs rely on milk that can be up to 30 percent fat and adults eat primarily blubber of marine mammal prey. Polar bears have large fat deposits under their skin and, because they essentially live in a polar desert and don't have access to fresh water for most of the year, rely on metabolic water, which is a byproduct of the breakdown of fat."

She noted that the evolution of a new metabolism to deal with high dietary fat must have happened very quickly, in just a few hundred thousand years, because we know that polar bears already subsisted on a marine diet 100,000 years ago.

What drove the evolution of polar bears is unclear, though the split from brown bears (dated at 343,000-479,000 years ago) coincides with a particularly warm 50,000-year interglacial period known as Marine Isotope Stage 11. Environmental shifts following climate changes could have encouraged brown bears to extend their range much farther north. When the warm interlude ended and a glacial cold period set in, a pocket of brown bears may have become isolated and forced to adapt rapidly to new conditions.

Samples from all over Arctic

The analysis included blood and tissue samples from 79 Greenlandic polar bears and 10 brown bears from Sweden, Finland, Glacier National Park in Alaska and the Admiralty, Baranof, and Chichagof (ABC) Islands off the Alaskan coast.

According to Lorenzen, the "key that allowed us to unlock the door of polar bear evolution" was a method devised by UC Berkeley mathematics graduate student Kelley Harris that has been used to estimate human demographic history. The approach, referred to as the identity by state (IBS) tract method, has proved powerful in estimating when ancient human populations diverged, their past population sizes and when and how much they interbred.

The work at UC Berkeley was supported by the National Institute of General Medical Sciences of the National Institutes of Health (2R14003229-07).
RELATED INFORMATION

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Polar bear genome gives new insight into adaptations to high-fat diet

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A comparison of the genomes of polar bears and brown bears reveals that the polar bear is a much younger species than previously believed, having diverged from brown bears less than 500,000 years ago. The analysis also uncovered several genes that may be involved in the polar bears' extreme adaptations to life in the high Arctic.

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Scenario 3: Study finds starfish shed arms to protect against overheating

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Scenario 3: Study finds starfish shed arms to protect against overheating

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Link to article: https://phys.org/news/2013-05-starfish-arms-overheating.html

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A Starfish in Mauritius. Credit: Alain Feulvarch/Wikipedia

(Phys.org) -A team of marine biologists has found that some starfish lose a leg when faced with too-warm environmental conditions. In their paper published in The Journal of Experimental Biology, the researchers describe what they witnessed as they subjected 70 starfish to various heated environments and filmed the results with infrared cameras.

Starfish are considered to be a cold-blooded animal-they can't adjust their internal temperature as environmental temperatures change. Because of this, they are at the mercy of weather conditions. This can be a problem for them when tidewater recedes leaving them stranded on a beach exposed to the hot sun. Until now, most biologists have believed that starfish, like most other cold blooded animals, have a uniform internal body temperature reflective of the temperature around them.

To find out how the starfish survived changes in heat, the research team captured 70 ochre starfish found living off the California shore and subjected them to heat related tests. Groups of the starfish were put into different tanks with different temperatures and were then filmed using an infrared camera to see what was going on with heat distribution inside of their bodies. To their surprise, they found that the temperature in the legs of the starfish was different than that of their core-the disk at the center of their legs that holds their vital organs. They also found that starfish have a definite limit on core temperature-if it reaches 35 C they die. Most remarkably of all they discovered that if the starfish were subjected to high temperatures for very long, they would engage in abscission (intentional shedding of a body part) of their legs.

More specifically, the team found that all of the starfish were able to keep their central disk 3 C to 5 C cooler than their arms, suggesting that the animals were using their legs as heat sinks. In extreme cases, the diversion of heat to arms would cause the arms to shrivel up and fall off-though that shouldn't be a problem for them as starfish are able to regenerate lost legs.

The findings by the team are the first time that arm loss in an animal has been seen to be attributable to thermal regulation. They also show that not all starfish leg loss is due to predators.

More information: Survival and arm abscission are linked to regional heterothermy in an intertidal sea star, J Exp Biol 216, 2183-2191 doi: 10.1242/jeb.083881 , June 15, 2013.

Abstract
Body temperature is a more pertinent variable to physiological stress than ambient air temperature. Modeling and empirical studies on the impacts of climate change on ectotherms usually assume that body temperature within organisms is uniform. However, many ectotherms show significant within-body temperature heterogeneity. The relationship between regional heterothermy and the response of ectotherms to sublethal and lethal conditions remains underexplored. We quantified within-body thermal heterogeneity in an intertidal sea star (Pisaster ochraceus) during aerial exposure at low tide to examine the lethal and sublethal effects of temperatures of different body regions. In manipulative experiments, we measured the temperature of the arms and central disc, as well as survival and arm abscission under extreme aerial conditions. Survival was related strongly to central disc temperature. Arms were generally warmer than the central disc in individuals that survived aerial heating, but we found the reverse in those that died. When the central disc reached sublethal temperatures of 31-35°C, arms reached temperatures of 33-39°C, inducing arm abscission. The absolute temperature of individual arms was a poor predictor of arm abscission, but the arms lost were consistently the hottest at the within-individual scale. Therefore, the vital region of this sea star may remain below the lethal threshold under extreme conditions, possibly through water movement from the arms to the central disc and/or evaporative cooling, but at the cost of increased risk of arm abscission. Initiation of arm abscission seems to reflect a whole-organism response while death occurs as a result of stress acting directly on central disc tissues.

© 2013 Phys.org

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Study finds starfish shed arms to protect against overheating

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(Phys.org) -A team of marine biologists has found that some starfish lose a leg when faced with too-warm environmental conditions. In their paper published in The Journal of Experimental Biology, the researchers describe what they witnessed as they subjected 70 starfish to various heated environments and filmed the results with infrared cameras.

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Scenario 5: DNA reveals how pitcher plants evolved to become flesh-eaters

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Scenario 5: DNA reveals how pitcher plants evolved to become flesh-eaters

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Link to article: https://www.abc.net.au/news/science/2017-02-07/dna-reveals-how-pitcher-plants-evolved-flesh-eaters/8243994

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Carnivorous plants around the world all developed their killer habit in surprisingly similar fashion, according to a genetic study of distantly related pitcher plants from Australia, Asia and America.

Scientists sequence genome of Australian pitcher plant to reveal which genes are involved with digestive fluids

Comparing with other species reveals genetic make-up of digestive enzymes is very similar

Finding suggests all plants took the same evolutionary route towards becoming predators

The plants became flesh-eaters as a means of making their own "fertiliser".

Findings published today in Nature Ecology and Evolution show while the three species evolved independently in different parts of the world over time, the biological processes they use to digest insects are incredibly alike.

Co-author Victor Albert, from Buffalo University, said the finding suggested there were limited evolutionary pathways by which plants could develop flesh-eating traits.

Carnivorous plants grow in very nutrient-poor habitats and produce carbon through the usual photosynthetic processes, just like other plants.

However, Dr Albert said, because their habitats failed to provide enough phosphorus and nitrogen, nature's equivalent of "fertiliser", they had to develop unusual ways to collect these nutrients.

"The animals [they prey on] have this in abundance in the form of the proteins and nucleic acids that are released when the plant digests them," he said.

Australian pitcher plant genome provides clues

Pitcher plants capture insects by luring them into a trap - a cupped leaf with a waxy, slippery interior that makes it difficult to climb out. A "soup" of digestive fluids sits at the bottom of this chamber and breaks down the flesh and exoskeletons of prey.

To better understand how these flesh-eating plants evolved, Dr Albert and colleagues mapped the genome of Cephalotus follicularis, a pitcher plant that is native to south-west Australia and closely related to star fruit.

"Cephalotus was a great plant to study because the plants bear two different kinds of leaves, one being the flat leaves, specialised for light gathering as in other plants, and the other being the elaborate pitchers used by the plants to capture prey," Dr Albert said.

By mapping its genome the team was able to uncover which genes were expressed only in pitcher leaves, and those related to photosynthetic leaves, or both.

"In this way, we were able to discern that several genes encoding digestive enzymes were preferentially expressed in [the pitcher plant] traps," he said.

The team then sequenced the digestive enzymes and digestive fluid proteins of this species and two other species: Asian pitcher plant Nepenthes alata, which is related to buckwheat, and the American pitcher plant Sarracenia purpurea, which is related to kiwi fruit.

This showed that over time, plant proteins previously used to fight disease and stress had evolved into the digestive enzymes that break down the insects' bodies.

"While we knew that carnivorous pitcher plants had evolved three different times, independently, from within different lineages of flowering plants, we didn't realise until now that the protein families used by these plants for their digestive functions had been repurposed independently as well," he said.

"Even more exciting was that within some of these enzyme families ... changes in the amino acid sequences of the proteins also occurred convergently."

Some of the critical enzymes evolved entirely separately, in different places.(Flickr: I-saint )

In other words, some of the critical enzymes evolved entirely separately, in different places and lineages.

These included chitinase, which breaks down chitin - the major component of insects' exoskeletons - and purple acid phosphatase, which enables plants to obtain phosphorus from its prey's body parts.

Dr Albert said the finding was an example of "nested convergence" - convergent evolution at several hierarchical levels.

These were morphological (pitchers are very similar yet develop totally differently in the three pitcher plant groups); genetic (convergent use of the same or similar enzyme groups); and molecular (amino acids show some convergent changes only in the carnivores).

"These plants have a genetic tool kit, and they're trying to come up with an answer to the problem of how to become carnivorous. And in the end, they all come up with the same solution," Dr Albert said.

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How pitcher plants evolved to become flesh-eaters

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Carnivorous plants around the world all developed their killer habit in surprisingly similar fashion, according to a genetic study of distantly related pitcher plants from Australia, Asia and America.