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Primary vs secondary: Primary is when there is nothing and something starts to grow from it slowly.

Secondary is when a major event happens to wipe out the established organisms and leaves nothing, then something starts to grow slowly.

Pioneer species: are the first to appear during secondary succession. Hardly little organisms that thrive from the harsh environment left behind.

It takes a lot of time for the environment to be able to support any kind of life at all, especially after secondary succession. Look at the fires in California and Australia. The grounds are bare and bone dry, as they will stay for a long time.

Deforestation is a common human-induced secondary succession, especially in the Amazon Rainforest. If deforestation continues, by 2030 the forest will have lost 27% of its trees, which support all forms of life. This insane lose of habitat accounts for a secondary succession that will take centuries to fix.

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"Temperature range in the summer gets as low as -7° C (20° F). The high in summer can be 21° C (70° F). The summers are mostly warm, rainy and humid. They are also very short with about 50 to 100 frost free days. The total precipitation in a year is 30 - 85 cm (12 - 33 in) . The forms the precipitation comes in are rain, snow and dew. Most of the precipitation in the taiga falls as rain in the summer. (https://blueplanetbiomes.org/taiga.php)" "The main seasons in the taiga are winter and summer. The spring and autumn are so short, you hardly know they exist. It is either hot and humid or very cold in the taiga.(https://blueplanetbiomes.org/taiga.php)"

Both flora and fauna are present, and both are heavily adapted to the chilly weather. Elk and the grey wolf have thick coats of fur to keep them warm, while evergreens take any sun they can get by staying green all year round.

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The taiga is a forest of the cold, subarctic region. The subarctic is an area of the Northern Hemisphere that lies just south of the Arctic Circle.

Subjects

Biology, Earth Science, Geography, Physical Geography

The taiga is a forest of the cold, subarctic region. The subarctic is an area of the Northern Hemisphere that lies just south of the Arctic Circle. The taiga lies between the tundra to the north and temperate forests to the south.

Alaska, Canada, Scandinavia, and Siberia have taigas. In Russia, the world's largest taiga stretches about 5,800 kilometers (3,600 miles), from the Pacific Ocean to the Ural Mountains. This taiga region was completely glaciated, or covered by glaciers, during the last ice age.

The soil beneath the taiga often contains permafrost-a layer of permanently frozen soil. In other areas, a layer of bedrock lies just beneath the soil. Both permafrost and rock prevent water from draining from the top layers of soil. This creates shallow bogs known as muskegs. Muskegs can look like solid ground, because they are covered with moss, short grasses, and sometimes even trees. However, the ground is actually wet and spongy.

Plants and Fungi

Taigas are thick forests. Coniferous trees, such as spruce, pine, and fir, are common. Coniferous trees have needles instead of broad leaves, and their seeds grow inside protective, woody cones. While deciduous trees of temperate forests lose their leaves in winter, conifers never lose their needles. For this reason, conifers are also called "evergreens."

Conifers have adapted to survive the long, cold winters and short summers of the taiga. Their needles contain very little sap, which helps prevent freezing. Their dark color and triangle-shaped sides help them catch and absorb as much of the sun's light as possible. In the taiga, tree growth is thickest beside muskegs and lakes formed by glaciers.

Taigas have few native plants besides conifers. The soil of the taiga has few nutrients. It can also freeze, making it difficult for many plants to take root. The larch is one of the only deciduous trees able to survive in the freezing northern taiga.

Instead of shrubs and flowers, mosses, lichens, and mushrooms cover the floor of a taiga. These organisms can grow directly on the ground, or have very shallow roots. They can survive in the cold, and with little water or sunlight.

Animals of the Taiga

Many kinds of animals live in the taiga. All animals have to be well-adapted to the cold. Birds native to the taiga usually migrate south during the freezing winter months. Small animals, mostly rodents, live close to the floor. Many birds of prey, such as owls and eagles, hunt these animals from the trees of the taiga.

Moose, the largest type of deer in the world, is able to live in the cold taiga. Like all deer, moose are herbivores. They favor the aquatic plants growing on the taiga's bogs and streams.

Few large carnivorous animals live in the taiga. Bears and lynx are fairly common. The largest cat in the world, the 300-kilogram (660-pound) Siberian tiger, is a native taiga species. Siberian tigers live in a small part of eastern Siberia. They hunt moose and wild boars.

Threats to Taigas

Taiga ecosystems are threatened by direct human activity and climate change. Animals of the taiga, such as foxes or bears, have always been hunted. Their warm fur and tough skin, turned into leather, have helped people survive in harsh climates for thousands of years.

The most serious threat to taigas does not come from hunting activity, however. Civilization is dependent on sturdy buildings for homes, industry, and schools. The trees of the taiga are cut down for lumber projects, as well as paper, cardboard, and other supplies. The export of wood and paper products is one of the most economically important industries in Canada, for instance.

Clearcutting is the most popular type of logging in taigas. Clearcutting involves cutting down all the trees in a designated area. This destroys habitats for many organisms that live in and around the trees, and makes it difficult for new trees to grow. Clearcutting also increases the risk of erosion and flooding in the taiga. Without a root system to anchor it, a taiga's soil can be blown away by wind or worn away by rain or snow. This exposes the bedrock and permafrost beneath the taiga, which does not support many forms of life.

Climate change puts taigas in danger in different ways. Warming climate contributes to a partial thawing of the permafrost. Since this water has no place to drain, more area of the taiga is taken over by muskegs. Few trees take root.

Warming temperature also changes animal habitats. It pushes native species out and attracts non-native species. Animals such as the Siberian tiger are not adapted to warm weather. Its coat is too heavy, and it stores too much body fat to thrive in a temperate habitat. Non-native insects such as the bark beetle can infest trees such as spruce. Millions of these insects bore into the bark of trees, laying eggs. The infested trees die. Bark beetle infestations can kill entire forests and thousands of hectares of taiga.

Fast Fact

Tipsy Timber
In drunken forests, trees tilt in different directions. These trees arent tipsy from beer or other alcohol, but from taiga soil conditions. When permafrost layers in the soil thaw, the ground sags. This causes nearby trees, which have very shallow roots, to lean toward the depression.

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Mary Crooks, National Geographic Society

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Jeannie Evers, Emdash Editing, Emdash Editing

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National Geographic Society

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The taiga is a forest of the cold, subarctic region. The subarctic is an area of the Northern Hemisphere that lies just south of the Arctic Circle.

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Deserts usually get at most 50 centimeters (20 inches) of rainfall a year and temperatures vary depending on the type of desert.

Rocks/gravel, sand, and rocky sand.

Deserts cover 1/5 of Earth's surface. Since the only qualification is that they get less than 10 inches of rainfall a year, deserts are found on every continent. However, they are almost always landlocked and most commonly found at 30 degrees North as seen in the Sahara.

Both flora and fauna have adapted to life in the desert. Plants conserve water like cacti that have enlarged stems to store water, as well as spines to protect from  animals. Animals such as the black-tailed jackrabbit (Lepus californicus) are also adapted to life in the desert: Their extra-long ears help to transfer out excess heat from their body into the air. (https://www.nationalgeographic.org/encyclopedia/desert-biome/)

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Rainforests have very rich topsoil to provide nutrients for the abundance of life there. Located on or very close to the equator, rain forests thrive in  high temperature and high precipitation areas. The average daily temperatures range from 20°C (68°F) to 25°C (77°F) and receive the most rain of all of the biomes in a year! A typical year sees 2,000 to 10,000 millimeters (79 to 394 inches) of rain per year. (https://www.earthobservatory.nasa.gov/biome/biorainforest.php)
Rainforest need lots of sun exposure, as they are only found close to/on the equator. Because of this, they only see one season.

Flora is dominant but fauna is also very present. Giant trees provide a layer of vegetation that prevents much of the sunlight from reaching the ground. Thick, woody vines are also found in the canopy.  The middle layer, or understory, is made up of vines, smaller trees, ferns, and palms. A large number of plants from this level are used as common houseplants. Because of the small amount of sunlight and rainfall these plants receive, they adapt easily to home environments.

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"Precipitation in the temperate grasslands usually occurs in the late spring and early summer. The annual average is about 50.8 to 88.9 cm (20-35 inches). The temperature range is very large over the course of the year. Summer temperatures can be well over 38° C (100 degrees Fahrenheit), while winter temperatures can be as low as -40° C (-40 degrees Fahrenheit). (Berkeley 1)"

Sand, grass, top soil, and rock are most prevalent.

"Most common at mid-latitudes and near the interiors of continents. (https://www.thoughtco.com/overview-of-the-grassland-biome-130169)"

Grasslands are typically north of  the Tropic of Cancer,  specifically at 23.5 degrees north in latitude, and south of the Tropic of Capricorn, specifically at 23.5 degrees south in latitude. (https://www.eartheclipse.com/ecosystem/temperate-grassland-biome.html)  Days are long and hot, as there are no mountains to shield from the blazing sun.

Flora (wild grasses) are most prevalent in grasslands. They are the dominant vegetation that is home to many fauna, including insects, birds, toads, and small mammals.

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Home | Online exhibits | The world's biomes

Grasslands are characterized as lands dominated by grasses rather than large shrubs or trees. In the Miocene and Pliocene Epochs, which spanned a period of about 25 million years, mountains rose in western North America and created a continental climate favorable to grasslands. Ancient forests declined and grasslands became widespread. Following the Pleistocene Ice Ages, grasslands expanded in range as hotter and drier climates prevailed worldwide. There are two main divisions of grasslands:

Savanna

Savanna is grassland with scattered individual trees. Savannas of one sort or another cover almost half the surface of Africa (about five million square miles, generally central Africa) and large areas of Australia, South America, and India. Climate is the most important factor in creating a savanna. Savannas are always found in warm or hot climates where the annual rainfall is from about 50.8 to 127 cm (20-50 inches) per year. It is crucial that the rainfall is concentrated in six or eight months of the year, followed by a long period of drought when fires can occur. If the rain were well distributed throughout the year, many such areas would become tropical forest. Savannas which result from climatic conditions are called climatic savannas. Savannas that are caused by soil conditions and that are not entirely maintained by fire are called edaphic savannas. These can occur on hills or ridges where the soil is shallow, or in valleys where clay soils become waterlogged in wet weather. A third type of savanna, known as derived savanna, is the result of people clearing forest land for cultivation. Farmers fell a tract of forest, burn the dead trees, and plant crops in the ashes for as long as the soil remains fertile. Then, the field is abandoned and, although forest trees may recolonize, grass takes over on the bare ground (succession), becoming luxuriant enough to burn within a year or so. In Africa, a heavy concentration of elephants in protected parkland have created a savanna by eating leaves and twigs and breaking off the branches, smashing the trunks and stripping the bark of trees. Elephants can convert a dense woodland into an open grassland in a short period of time. Annual fires then maintain the area as a savanna.

The soil of the savanna is porous, with rapid drainage of water. It has only a thin layer of humus (the organic portion of the soil created by partial decomposition of plant or animal matter), which provides vegetation with nutrients. Savannas are sometimes classified as forests. The predominant vegetation consists of grasses and forbs (small broad-leaved plants that grow with grasses). Different savannas support different grasses due to disparities in rainfall and soil conditions. Because the savanna supports such a large number of species competing for living space, usually only one or a few kinds of grass are more successful than the others in a particular area. For example, in drier savannas such as those on the Serengeti plains or Kenya's Laikipia plateau, the dominant grasses on well-drained soils are Rhodes grass and red oat grass; throughout the East African savannas, star grasses are dominant; the lemon grasses are common in many western Uganda savannas. Deciduous trees and shrubs are scattered across the open landscape. One type of savanna common in southwestern Kenya, Tanzania, and Uganda, known as grouped-tree grassland, has trees growing only on termite mounds — the intervening soil being too thin or poorly drained to support the growth of trees at all. Frequent fires and large grazing mammals kill seedlings, thus keeping the density of trees and shrubs low. Savannas receive an average annual rainfall of 76.2-101.6 cm (30-40 inches).

Savanna has both a dry and a rainy season. Seasonal fires play a vital role in the savanna's biodiversity. In October, a series of violent thunderstorms, followed by a strong drying wind, signals the beginning of the dry season. Fire is prevalent around January, at the height of the dry season. Fires in savannas are often caused by poachers who want to clear away dead grass to make it easier to see their prey. The fires do not devastate the community. Most of the animals killed by the fires are insects with short life spans. A fire is a feast for some animals, such as birds that come to sites of fires to eat grasshoppers, stick insects, beetles, mice, and lizards that are killed or driven out by the fire. Underground holes and crevices provide a safe refuge for small creatures. Larger animals are usually able to run fast enough to escape the fire. Although the dry stems and leaves of grasses are consumed by fire, the grasses' deep roots remain unharmed. These roots, with all their starch reserves, are ready to send up new growth when the soil becomes more moist. The scattered shrubs can also subsist on food reserves in their roots while they await the time to venture above the soil again. Unlike grasses and shrubs, trees survive a fire by retaining some moisture in all their above-ground parts throughout the dry season. Sometimes they have a corky bark or semisucculent trunk covered with smooth resinous bark, both being fire resistant. A fire leaves scorched earth covered with a fine layer of powdery black ash in its wake. During March, violent thunderstorms occur again, this time heralding the rainy season. When the rains come, savanna bunch grasses grow vigorously. Some of the larger grasses grow an inch or more in 24 hours. The savannas experiences a surge of new life at this time. For example, many antelope calves are born. With so much grass to feed on, mothers have plenty of milk. Calves die if the rains fail to come.

Other animals (which do not all occur in the same savanna) include giraffes, zebras, buffaloes, kangaroos, mice, moles, gophers, ground squirrels, snakes, worms, termites, beetles, lions, leopards, hyenas, and elephants.

There are also some environmental concerns regarding savannas such as poaching, overgrazing, and clearing of the land for crops.

Temperate grassland

Temperate grasslands are characterized as having grasses as the dominant vegetation. Trees and large shrubs are absent. Temperatures vary more from summer to winter, and the amount of rainfall is less in temperate grasslands than in savannas. The major manifestations are the veldts of South Africa, the puszta of Hungary, the pampas of Argentina and Uruguay, the steppes of the former Soviet Union, and the plains and prairies of central North America. Temperate grasslands have hot summers and cold winters. Rainfall is moderate. The amount of annual rainfall influences the height of grassland vegetation, with taller grasses in wetter regions. As in the savanna, seasonal drought and occasional fires are very important to biodiversity. However, their effects aren't as dramatic in temperate grasslands as they are in savannas. The soil of the temperate grasslands is deep and dark, with fertile upper layers. It is nutrient-rich from the growth and decay of deep, many-branched grass roots. The rotted roots hold the soil together and provide a food source for living plants. Each different species of grass grows best in a particular grassland environment (determined by temperature, rainfall, and soil conditions). The seasonal drought, occasional fires, and grazing by large mammals all prevent woody shrubs and trees from invading and becoming established. However, a few trees, such as cottonwoods, oaks, and willows grow in river valleys, and some nonwoody plants, specifically a few hundred species of flowers, grow among the grasses. The various species of grasses include purple needlegrass, blue grama, buffalo grass, and galleta. Flowers include asters, blazing stars, coneflowers, goldenrods, sunflowers, clovers, psoraleas, and wild indigos.

Precipitation in the temperate grasslands usually occurs in the late spring and early summer. The annual average is about 50.8 to 88.9 cm (20-35 inches). The temperature range is very large over the course of the year. Summer temperatures can be well over 38° C (100 degrees Fahrenheit), while winter temperatures can be as low as -40° C (-40 degrees Fahrenheit).

The fauna (which do not all occur in the same temperate grassland) include gazelles, zebras, rhinoceroses, wild horses, lions, wolves, prairie dogs, jack rabbits, deer, mice, coyotes, foxes, skunks, badgers, blackbirds, grouses, meadowlarks, quails, sparrows, hawks, owls, snakes, grasshoppers, leafhoppers, and spiders.

There are also environmental concerns regarding the temperate grasslands. Few natural prairie regions remain because most have been turned into farms or grazing land. This is because they are flat, treeless, covered with grass, and have rich soil.

Temperate grasslands can be further subdivided. Prairies are grasslands with tall grasses while steppes are grasslands with short grasses. Prairie and steppes are somewhat similar but the information given above pertains specifically to prairies — the following is a specific description of steppes.

Steppes are dry areas of grassland with hot summers and cold winters. They receive 25.4-50.8 cm (10-20 inches) of rainfall a year. Steppes occur in the interiors of North America and Europe. Plants growing in steppes are usually greater than 1 foot tall. They include blue grama and buffalo grass, cacti, sagebrush, speargrass, and small relatives of the sunflower. Steppe fauna includes badgers, hawks, owls, and snakes. Today, people use steppes to graze livestock and to grow wheat and other crops. Overgrazing, plowing, and excess salts left behind by irrigation waters have harmed some steppes. Strong winds blow loose soil from the ground after plowing, especially during droughts. This causes the dust storms of the Great Plains of the U.S.

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Home | Online exhibits | The world's biomes Grasslands are characterized as lands dominated by grasses rather than large shrubs or trees. In the Miocene and Pliocene Epochs, which spanned a period of about 25 million years, mountains rose in western North America and created a continental climate favorable to grasslands.

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"The average daily temperatures range between -30°C (-22°F) and 30°C (86°F) with a yearly average of 10°C (50°F). Hot summers and cold winters are typical in this biome, receiving 750 to 1,500 millimeters (30 to 59 inches) of rain per year. (https://www.earthobservatory.nasa.gov/biome/biotemperate.php)"

Soil and mountians are commonly found to provide for the trees.

Most occur around 60 degrees North. As the seasons change, leaves lose their leaves and grow new ones in the spring.

Flora is most present, but supports a lot of fauna. Since the change in seasons are so drastic, these organisms grow and shed layers respectably. Mammals grow fur, and trees grow leave, when they then drop in order to save energy through the winter.

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Benthos:  Crustaceans, worms and leeches, insect larvae, clams and mussels, snails. Mollusks include Bellamya, Gabbiella, Melanoides, Bulinus, Biomphalaria and Cleopatra (Gastropoda) and Corbicula, Eupera (Byssanodonta), Caelatura and Sphaerium (Bivalvia) (https://www.researchgate.net/publication/272342001_The_diversity_of_benthic_mollusks_of_Lake_Victoria_and_Lake_Burigi)
Nekton : Nile perch, nile tilapia, and dagaa (http://www.globalgreatlakes.org/agl/victoria/)
Plankton: Cyanobacteria, Anabaena, Microcystis (https://www.sciencedirect.com/science/article/pii/S0075951110000186)
Location: Tanzania and Uganda
Length/width/area: 26,828 square miles, 210 by 150 at its longest/widest respectively
Depth: 270 feet at deepest
Temperature: 70-77 degrees F
(https://www.britannica.com/place/Lake-Victoria)

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Benthos:   The benthic community of Lake Turkana includes a sponge, a bryozoan, 8 gastropods, 3 bivalves, 17 ostracods, 23 insects and several hydracarines and annelids. Caridina nilotica, Potamonautes niloticus (Crustacea), Limnodrilus hoffmeisteri, Branchiura sowerbyi (Oligochaeta), Corbicula fluminalis, Cleopatra bulimoides and Melanoides tuberculata (Mollusca) https://link.springer.com/chapter/10.1007/978-1-4020-9726-3_28
Nekton : Crocodiles, perch, toads, monitor lizards, smaller fish
Plankton: abundacne of zooplankton to provide food for the food chain.
Location: Tanzania, Burundi, Rwanda, the Democratic Republic of the Congo, Kenya, Uganda, South Sudan, Ethiopia, Sudan, and Egypt. https://www.britannica.com/place/Nile-River
Length/width/area: 4,132 miles long, 1.7 miles wide at most, covers 1,293,000 square miles total
Depth: 26-36 feet deep
Temperature: 60-80 degrees F https://www.britannica.com/place/Nile-River/Climate-and-hydrology

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Benthos:  2,180 species of flowering plants,
Nekton: crocodiles, hippopotami, various birds and invertebrates. (https://en.wikipedia.org/wiki/Lake_St._Lucia)
Plankton: Abundant phytoplankton in St Lucia's estuary system provided a healthy start to the food chain.
Location: South Africa
Length/width/area: 43.5 km by  22.5 km, 140 square miles
Depth: 0.9 meters
Temperature: 70's degrees F

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Rock erosion: gradually releases phosphorus as phosphate ions which are soluble in water
Absorption: Released from rocks and absorbed by plants.
Consumption:  Plants are then eaten by animals.
Decomposition: Animals die and decompose, releasing the phosphorus back into the soil and rocks.
Uplifting and or sedimentation: Oceanic sedimentary rock that becomes land overtime.

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Evaporation: Less evaporation farther north, more as you head south. Most evaporation in summer months.
Condensation: Lack of clouds in summer, more in winter.
Precipitation: Depending on how far north in the river you are and what time of year it is, precipitation is anywhere from 0-400mm. 0 would be North in the winter, 400 would be South in the summer. (http://www.waterandclimatechange.eu/rainfall/nile-river-basin-rainfall-in-average-year)
Collection: The Nile swells in the summer due to flooding, and runs lower in the winter due to lack of rainfall.
Transpiration: Typically, there is no transpiration in the Nile River due to the fact that it is a river... full of water... for the plants to drink. However, when the water levels lower in the winter, plants may develop plasmolysis due to drought.
Run off: Run off carries out erosion in the Nile River basin, leading to build up at the delta.

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"Temperatures usually range between -40°C (-40 °F) and 18°C (64°F). This biome sees 150 to 250 millimeters (6 to 10 inches) of rain per year. (https://www.earthobservatory.nasa.gov/biome/biotundra.php)"

Snow, frost, ice and rock are most common. Usually found in the Artic and antartic circles, tundras are frozen biomes of permefrost and ice, all year round. Due to lack of sun exposure, the temperature stays below 0 degrees C for 6-10 months of the year.

With almost no flora since its an ice desert, the limited fauna that can survive there do so by extreme measures. Thick layers of flubber and fur keep some animals warm, while others burrow into the snow for protection from the wind.

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Nitrogen fixation: molecular nitrogen in the air is converted into ammonia or related nitrogenous compounds in soil.

Absorption: when nitrogen is absorbed by the soil, bacteria help it to change states so it can be absorbed by plants.

Consumption: Animals get their nitrogen from plants.

Decomposition: Animals die and decompose, returning the nitrogen to the bacteria in the soil.

Denitrification: reduction of soil nitrate to nitrogen-containing gases, such as nitric oxide, nitrous oxide, and nitrogen gas, takes place.

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1.  Photosynthesis: CAM plants save energy by a less efficient but more effective process that conserves water over extended periods of time. Cacti are a great example. Photosynthesis pulls carbon out of the atmosphere, along with water and sunlight energy. and puts out glucose and oxygen.

2.  Cellular Respiration: Cellular respiration takes in glucose and oxygen and puts out energy and carbon into the atmosphere.

3.  Consumption: Usually demonstrated as animals eating, consumption is the act of taking something in for energy. For example, a ground squirrel eating wild grasses and nuts.

4.  Decomposition: Throwback to the Wild Wild West with tumble weeds and oxen skulls in the middle of the desert. Decomposition is self descriptive; decomposing matter. A hawk might leave behind the rejects of a rabbit it killed to decomposed and be reabsorbed into the earth.

5.  Decay: Abiotic matter that is broken down to provide the earth with nutrients.

6.  Burning:  Whether it be brush or fossil fuels, burning anything is a chemical change that releases carbon back into the atmosphere.