The word tundra derives from the Finnish word for barren or treeless land. The tundra is the simplest biome in terms of species composition and food chains.
Vegetation: lichens, mosses, sedges, perennial forbs, and dwarfed shrubs, (often heaths, but also birches and willows).
Growthforms: typical are ground-hugging and other warmth-preserving forms including:
tussock-forming graminoids
mats or cushion plants, often evergreen members of the heath family
rosettes
dwarf shrubs, some of which are deciduous in habit
Climate: The high latitude conditions of Koeppen's ET climate type that impact life in this biome include
extremely short growing season (6 to 10 weeks)
long, cold, dark winters (6 to 10 months with mean monthly temperatures below 32° F or 0° C.)
low precipitation (less than five inches/year) coupled with strong, drying winds. Snowfall is actually advantageous to plant and animal life as it provides an insulating layer on the ground surface.
Edaphic controls: Permafrost, not cold temperatures per se, is generally believed to be what prevents tree growth. Furthermore, freeze-thaw activity, a thin active layer, and solifluction during the warmer months contribute to strong controls on vegetation patterns and create a mosaic of microhabitats and plant communities.
Soil: No true soil is developed in this biome due to the edaphic factors mentioned above.
Fauna: Strategies evolved to withstand the harsh conditions of the tundra can be divided among those species that are resident and those that are migratory.
Animals of the tundra: small number of bird (e.g., ptarmigan) mammals (e.g., muskox, arctic hare, arctic fox, musk ox) reside year-round on the tundra
Tuesday, October 5, 2010
Pre-AP Vocabulary List
Emergent: The top layer of the tropical rainforest
Intolerant: Not able to withstand
Vegetation: Plant life
Predator: An animal that preys on other animals (kills then eats)
Diverse: A wide variety
Sparse: Spread out, few in number
Vital: Very important; of or relating to life
Consumption: To take something in; to use up; to eat
Vary: To change
Favorable: Having an advantage
Herbivore: An animal that eats plants
Dominated: To take over; to govern; to rule
Temperate: Mild and balanced
Tropical: Something originating in the tropics or close to the equator
Qualitative: Measurements based on senses
Quantitative: Measurements based on numbers
Precision: The ability of a measurement to be reproduced
Accuracy: Coming up with the right answer
Hypothesis: An educated guess
X-Axis: The horizontal line on a line graph
Y-Axis: The vertical line on a line graph
Intolerant: Not able to withstand
Vegetation: Plant life
Predator: An animal that preys on other animals (kills then eats)
Diverse: A wide variety
Sparse: Spread out, few in number
Vital: Very important; of or relating to life
Consumption: To take something in; to use up; to eat
Vary: To change
Favorable: Having an advantage
Herbivore: An animal that eats plants
Dominated: To take over; to govern; to rule
Temperate: Mild and balanced
Tropical: Something originating in the tropics or close to the equator
Qualitative: Measurements based on senses
Quantitative: Measurements based on numbers
Precision: The ability of a measurement to be reproduced
Accuracy: Coming up with the right answer
Hypothesis: An educated guess
X-Axis: The horizontal line on a line graph
Y-Axis: The vertical line on a line graph
The Desert Biome
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Deserts are defined as areas with an average annual precipitation of less than 250 millimeters (10 in) per year, or as areas where more water is lost by evapotranspiration than falls as precipitation. In the Köppen climate classification system, deserts are classed as BWh (hot desert) or BWk (temperate desert). In the Thornthwaite climate classification system, deserts would be classified as arid megathermal climates. Hot deserts usually have a large diurnal and seasonal temperature range, with high daytime temperatures, and low nighttime temperatures (due to extremely low humidity). In hot deserts the temperature in the daytime can reach 45 °C/113 °F or higher in the summer, and dip to 0 °C/32 °F or lower in the winter. Water acts to trap infrared radiation from both the sun and the ground, and dry desert air is incapable of blocking sunlight during the day or trapping heat during the night. Thus, during daylight most of the sun's heat reaches the ground, and as soon as the sun sets the desert cools quickly by radiating its heat into space. Urban areas in deserts lack large (more than 14 °C/25 °F) daily temperature variations, partially due to the urban heat island effect.
Many deserts are formed by rain shadows; mountains blocking the path of precipitation to the desert (on the lee side of the mountain). Deserts are often composed of sand and rocky surfaces. Sand dunes called ergs and stony surfaces called Hamada surfaces compose a minority of desert surfaces. Exposures of rocky terrain are typical, and reflect minimal soil development and sparseness of vegetation. The soil is rocky because of the low chemical weathering.
Bottomlands may be salt-covered flats. Eolian processes are major factors in shaping desert landscapes. Polar deserts (also seen as "cold deserts") have similar features, except the main form of precipitation is snow rather than rain. Antarctica is the world's largest cold desert (composed of about 98 percent thick continental ice sheet and 2 percent barren rock). Some of the barren rock is to be found in the so-called Dry Valleys of Antarctica that almost never get snow, which can have ice-encrusted saline lakes that suggest evaporation far greater than the rare snowfall due to the strong katabolic winds that evaporate even ice.
Measurement of rainfall alone cannot provide an accurate definition of what a desert is because being arid also depends on evaporation, which depends in part on temperature. For example, Phoenix, Arizona receives less than 250 millimeters (10 in) of precipitation per year, and is immediately recognized as being located in a desert due to its arid adapted plants. The North Slope of Alaska's Brooks Range also receives less than 250 millimeters (10 in) of precipitation per year and is often classified as a cold desert. Other regions of the world have cold deserts, including areas of the Himalayas and other high altitude areas in other parts of the world. Polar deserts cover much of the ice free areas of the arctic and Antarctic.
Many deserts are formed by rain shadows; mountains blocking the path of precipitation to the desert (on the lee side of the mountain). Deserts are often composed of sand and rocky surfaces. Sand dunes called ergs and stony surfaces called Hamada surfaces compose a minority of desert surfaces. Exposures of rocky terrain are typical, and reflect minimal soil development and sparseness of vegetation. The soil is rocky because of the low chemical weathering.
Bottomlands may be salt-covered flats. Eolian processes are major factors in shaping desert landscapes. Polar deserts (also seen as "cold deserts") have similar features, except the main form of precipitation is snow rather than rain. Antarctica is the world's largest cold desert (composed of about 98 percent thick continental ice sheet and 2 percent barren rock). Some of the barren rock is to be found in the so-called Dry Valleys of Antarctica that almost never get snow, which can have ice-encrusted saline lakes that suggest evaporation far greater than the rare snowfall due to the strong katabolic winds that evaporate even ice.
Measurement of rainfall alone cannot provide an accurate definition of what a desert is because being arid also depends on evaporation, which depends in part on temperature. For example, Phoenix, Arizona receives less than 250 millimeters (10 in) of precipitation per year, and is immediately recognized as being located in a desert due to its arid adapted plants. The North Slope of Alaska's Brooks Range also receives less than 250 millimeters (10 in) of precipitation per year and is often classified as a cold desert. Other regions of the world have cold deserts, including areas of the Himalayas and other high altitude areas in other parts of the world. Polar deserts cover much of the ice free areas of the arctic and Antarctic.
The Rainforest
The Rainforest
Rainforests are forests characterized by high rainfall, with definitions minimum normal annual rainfall between (68-78 inches). The monsoon trough, alternately known as the inter-tropical convergence zone, plays a significant role in creating Earth's tropical rain forests.
A total of 40 to 75% of all species on the world's habitats are indigenous to the rainforests. It has been estimated that many millions of species of plants, insects, and microorganisms are still undiscovered. Tropical rainforests have been called the "jewels of the Earth", and the "world's largest pharmacy", because over one quarter of natural medicines have been discovered there. Rainforests are also responsible for 28% of the world's oxygen turn over, often misunderstood as oxygen production, processing it through photosynthesis from carbon dioxide and storing it as carbon through bio-sequestration.
The undergrowth in a rainforest is restricted in many areas by the lack of sunlight at ground level. This makes it possible to walk through the forest. If the leaf canopy is destroyed or thinned, the ground beneath is soon colonized by a dense, tangled growth of vines, shrubs, and small trees called a jungle. There are two types of rainforest, tropical rainforest and temperate rainforest.
Tropical Rainforest
Many of the world's rainforests are associated with the location of the monsoon trough, also known as the inter-tropical convergence zone. Tropical rainforests are rainforests in the tropics, found near the Jamaica (between the Tropic of Cancer and Tropic of Capricorn) and present in Southeast Asia (Myanmar to Philippines, Indonesia, Papua New Guinea, and northeastern Australia), Sri Lanka, Sub-Saharan Africa from Cameroon to the Congo (Congo Rainforest), South America (e.g. the Amazon Rainforest), Central America (e.g. Bosawás, southern Yucatán Peninsula-El Peten-Belize-Calakmul), and on many of the Pacific Islands (such as Hawaiʻi). Tropical rainforests have been called the "Earth's lungs," although it is now known that rainforests contribute little net oxygen additions to the atmosphere through photosynthesis.
Temperate rainforests are rainforests in temperate regions.
Layers of the Rainforest
A tropical rainforest is typically divided into four main layers, each with different plants and animals adapted for life in that particular area: the emergent, canopy, understory, and forest floor layers.
Emergent layer of the Rainforest
The emergent layer contains a small number of very large trees called emergents, which grow above the general canopy, reaching heights of 45–55 m, although on occasion a few species will grow to 70–80 m tall.[7][8] They need to be able to withstand the hot temperatures and strong winds in some areas. Eagles, butterflies, bats, and certain monkeys inhabit this layer.
Canopy layer
The canopy layer contains the majority of the largest trees, typically 30–45 m tall. The densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 50 percent of all plant species, suggesting that perhaps half of all life on Earth could be found there. Epiphytic plants attach to trunks and branches, and obtain water and minerals from rain and debris that collects on the supporting plants. The fauna is similar to that found in the emergent layer, but more diverse. A quarter of all insect species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, but have only recently developed practical methods of exploring it. As long ago as 1917, naturalist William Beebe declared that "another continent of life remains to be discovered, not upon the Earth, but one to two hundred feet above it, extending over thousands of square miles." True exploration of this habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows. Exploration of the canopy is still in its infancy, but other methods include the use of balloons and airships to float above the highest branches and the building of cranes and walkways planted on the forest floor. The science of accessing tropical forest canopy using airships, or similar aerial platforms, is called dendronautics.[9]
Understory layer
The understory layer lies between the canopy and the forest floor. The understory) is home to a number of birds, snakes, and lizards, as well as predators such as jaguars, boa constrictors, and leopards. The leaves are much larger at this level. Insect life is also abundant. Many seedlings that will grow to the canopy level are present in the understory. Only about 5% of the sunlight shining on the rainforest reaches the understory. This layer can also be called a shrub layer, although the shrub layer may also be considered a separate layer.
Forest floor
The forest floor, the bottom-most layer, receives only 2% of sunlight. Only plants adapted to low light can grow in this region. Away from riverbanks, swamps, and clearings where dense undergrowth is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. It also contains decaying plant and animal matter, which disappears quickly due to the warm, humid conditions promoting rapid decay. Many forms of fungi grow here which help decay the animal and plant waste.
Plants and animals
More than half of the world's species of plants and animals are found in the rainforest. Rainforests support a very broad array of fauna including mammals, reptiles, birds, and invertebrates. Mammals may include primates, felids, and other families. Reptiles include snakes, turtles, chameleons, and other families. Dozens of families of invertebrates are found in rainforests. Fungi are also very common in rainforest areas as they can feed on the decomposing remains of plant and animal life. These species are rapidly disappearing due to deforestation, habitat loss, and biochemical releases into the atmosphere.
Soils
Despite the growth of vegetation in a tropical rainforest, soil quality is often quite poor. Rapid bacterial decay prevents the accumulation of humus. Most trees have roots near the surface as there are not many nutrients below the ground; most of the trees minerals come from the top layer of decomposing leaves (mainly) and animals. On younger substrates, especially of volcanic origin, tropical soils may be quite fertile. If the trees are cleared, the rain can get at the exposed soil, washing it away.
Rainforests are forests characterized by high rainfall, with definitions minimum normal annual rainfall between (68-78 inches). The monsoon trough, alternately known as the inter-tropical convergence zone, plays a significant role in creating Earth's tropical rain forests.
A total of 40 to 75% of all species on the world's habitats are indigenous to the rainforests. It has been estimated that many millions of species of plants, insects, and microorganisms are still undiscovered. Tropical rainforests have been called the "jewels of the Earth", and the "world's largest pharmacy", because over one quarter of natural medicines have been discovered there. Rainforests are also responsible for 28% of the world's oxygen turn over, often misunderstood as oxygen production, processing it through photosynthesis from carbon dioxide and storing it as carbon through bio-sequestration.
The undergrowth in a rainforest is restricted in many areas by the lack of sunlight at ground level. This makes it possible to walk through the forest. If the leaf canopy is destroyed or thinned, the ground beneath is soon colonized by a dense, tangled growth of vines, shrubs, and small trees called a jungle. There are two types of rainforest, tropical rainforest and temperate rainforest.
Tropical Rainforest
Many of the world's rainforests are associated with the location of the monsoon trough, also known as the inter-tropical convergence zone. Tropical rainforests are rainforests in the tropics, found near the Jamaica (between the Tropic of Cancer and Tropic of Capricorn) and present in Southeast Asia (Myanmar to Philippines, Indonesia, Papua New Guinea, and northeastern Australia), Sri Lanka, Sub-Saharan Africa from Cameroon to the Congo (Congo Rainforest), South America (e.g. the Amazon Rainforest), Central America (e.g. Bosawás, southern Yucatán Peninsula-El Peten-Belize-Calakmul), and on many of the Pacific Islands (such as Hawaiʻi). Tropical rainforests have been called the "Earth's lungs," although it is now known that rainforests contribute little net oxygen additions to the atmosphere through photosynthesis.
Temperate rainforests are rainforests in temperate regions.
Layers of the Rainforest
A tropical rainforest is typically divided into four main layers, each with different plants and animals adapted for life in that particular area: the emergent, canopy, understory, and forest floor layers.
Emergent layer of the Rainforest
The emergent layer contains a small number of very large trees called emergents, which grow above the general canopy, reaching heights of 45–55 m, although on occasion a few species will grow to 70–80 m tall.[7][8] They need to be able to withstand the hot temperatures and strong winds in some areas. Eagles, butterflies, bats, and certain monkeys inhabit this layer.
Canopy layer
The canopy layer contains the majority of the largest trees, typically 30–45 m tall. The densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 50 percent of all plant species, suggesting that perhaps half of all life on Earth could be found there. Epiphytic plants attach to trunks and branches, and obtain water and minerals from rain and debris that collects on the supporting plants. The fauna is similar to that found in the emergent layer, but more diverse. A quarter of all insect species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, but have only recently developed practical methods of exploring it. As long ago as 1917, naturalist William Beebe declared that "another continent of life remains to be discovered, not upon the Earth, but one to two hundred feet above it, extending over thousands of square miles." True exploration of this habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows. Exploration of the canopy is still in its infancy, but other methods include the use of balloons and airships to float above the highest branches and the building of cranes and walkways planted on the forest floor. The science of accessing tropical forest canopy using airships, or similar aerial platforms, is called dendronautics.[9]
Understory layer
The understory layer lies between the canopy and the forest floor. The understory) is home to a number of birds, snakes, and lizards, as well as predators such as jaguars, boa constrictors, and leopards. The leaves are much larger at this level. Insect life is also abundant. Many seedlings that will grow to the canopy level are present in the understory. Only about 5% of the sunlight shining on the rainforest reaches the understory. This layer can also be called a shrub layer, although the shrub layer may also be considered a separate layer.
Forest floor
The forest floor, the bottom-most layer, receives only 2% of sunlight. Only plants adapted to low light can grow in this region. Away from riverbanks, swamps, and clearings where dense undergrowth is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. It also contains decaying plant and animal matter, which disappears quickly due to the warm, humid conditions promoting rapid decay. Many forms of fungi grow here which help decay the animal and plant waste.
Plants and animals
More than half of the world's species of plants and animals are found in the rainforest. Rainforests support a very broad array of fauna including mammals, reptiles, birds, and invertebrates. Mammals may include primates, felids, and other families. Reptiles include snakes, turtles, chameleons, and other families. Dozens of families of invertebrates are found in rainforests. Fungi are also very common in rainforest areas as they can feed on the decomposing remains of plant and animal life. These species are rapidly disappearing due to deforestation, habitat loss, and biochemical releases into the atmosphere.
Soils
Despite the growth of vegetation in a tropical rainforest, soil quality is often quite poor. Rapid bacterial decay prevents the accumulation of humus. Most trees have roots near the surface as there are not many nutrients below the ground; most of the trees minerals come from the top layer of decomposing leaves (mainly) and animals. On younger substrates, especially of volcanic origin, tropical soils may be quite fertile. If the trees are cleared, the rain can get at the exposed soil, washing it away.
The Taiga Biome
Taiga also known as the boreal forest, is a biome characterized by coniferous forests.
Taiga is the world's largest terrestrial biome and is found in North America most of inland Canada and Alaska as well as parts of the extreme northern continental United States.
The summers, while short, are generally warm and humid. In much of the taiga, -20 °C would be a typical winter day temperature and 18 °C an average summer day.
The growing season is when the vegetation in the taiga comes alive. The longest growing season is found in the smaller areas with oceanic influences; in coastal areas of Scandinavia and Finland, the growing season of the closed boreal forest can be 145 – 180 days. The shortest growing season is found at the northern taiga and is 50 – 70 days. High latitudes mean that the sun does not rise far above the horizon, and less solar energy is received than further south. But the high latitude also ensures very long summer days, as the sun stays above the horizon nearly 20 hours each day, with only around 6 hours of daylight occurring in the dark winters, depending on latitude. The areas of the taiga inside the Arctic Circle have midnight sun in mid-summer and polar night in mid-winter.
The taiga experiences relatively low precipitation throughout the year. Snow may remain on the ground for as long as nine months in the northernmost extensions of the taiga.
Much of the area currently classified as taiga was recently glaciated. As the glaciers receded, they left depressions in the topography that have since filled with water, creating lakes and bogs (especially muskeg soil), found throughout the taiga.
Much of the area currently classified as taiga was recently glaciated. As the glaciers receded, they left depressions in the topography that have since filled with water, creating lakes and bogs (especially muskeg soil), found throughout the taiga.
The forests of the taiga are largely coniferous, dominated by larch, spruce, fir, and pine.
Taigas have some small-leaved deciduous trees like birch, alder, willow, and poplar; mostly in areas escaping the most extreme winter cold.
There are two major types of taiga. The southern part is the closed canopy forest, consisting of many closely-spaced trees with mossy ground cover. In clearings in the forest, shrubs and wildflowers are common, such as the fireweed. The other type is the lichen woodland or sparse taiga, with trees that are farther-spaced and lichen ground cover; the latter is common in the northernmost taiga
Evergreen species in the taiga (spruce, fir, and pine) have a number of adaptations specifically for survival in harsh taiga winters. Taiga trees tend to have shallow roots to take advantage of the thin soils, while many of them seasonally alter their biochemistry to make them more resistant to freezing, called "hardening". The narrow conical shape of northern conifers, and their downward-drooping limbs, also helps them shed snow.
Because the sun is low in the horizon for most of the year, it is difficult for plants to generate energy from photosynthesis. Pine, spruce and fir do not lose their leaves seasonally and are able to photosynthesize with their older leaves in late winter and spring when light is good but temperatures are still too low for new growth to commence. The adaptation of evergreen needles limits the water lost due to transpiration and their dark green color increases their absorption of sunlight. Although precipitation is not a limiting factor, the ground freezes during the winter months and plant roots are unable to absorb water, so desiccation can be a severe problem in late winter for evergreens.
The boreal forest, or taiga, supports a large range of animals. Canada's boreal forest includes 85 species of mammals, 130 species of fish, and an estimated 32,000 species of insects. Insects play a critical role as pollinators, decomposers and as a part of the food chain; many nesting birds rely on them for food. The cold winter and short summers make the taiga a challenging biome for reptiles and amphibians, which depend on environmental conditions to regulate their body temperatures, and there are only a few species in the boreal forest. Some hibernate underground in winter.
The taiga is home to a number of large herbivorous mammals, such as moose and reindeer/caribou. Some areas of the more southern closed boreal forest also have populations of other deer species such as the elk (wapiti) and roe deer. There is also a range of rodent species, including beaver, squirrel, mountain hare, snowshoe hare and vole. These species have evolved to survive the harsh winters in their native ranges. Some larger mammals, such as bears, eat heartily during the summer in order to gain weight, and then go into hibernation during the winter. Other animals have adapted layers of fur or feathers to insulate them from the cold.
A number of wildlife species that are threatened or endangered can be found in the Canadian boreal forest, including woodland caribou, American black bear, grizzly bear and wolverine.
Predatory birds (owls and eagles) and other smaller carnivores, including foxes and weasels, feed on the rodents live here. Larger carnivores, such as lynx and wolves, prey on the larger animals. Omnivores, such as bears and raccoons are fairly common, sometimes picking through human garbage.
More than 300 species of birds have their nesting grounds in the taiga. Of the 300 species of birds that summer in the taiga, only 30 stay for the winter. These are either carrion-feeding or large raptors that can take live mammal prey, including Golden Eagle, Rough-legged Buzzard, and Raven, or else seed-eating birds, including several species of grouse and crossbills.
Taiga is the world's largest terrestrial biome and is found in North America most of inland Canada and Alaska as well as parts of the extreme northern continental United States.
The summers, while short, are generally warm and humid. In much of the taiga, -20 °C would be a typical winter day temperature and 18 °C an average summer day.
The growing season is when the vegetation in the taiga comes alive. The longest growing season is found in the smaller areas with oceanic influences; in coastal areas of Scandinavia and Finland, the growing season of the closed boreal forest can be 145 – 180 days. The shortest growing season is found at the northern taiga and is 50 – 70 days. High latitudes mean that the sun does not rise far above the horizon, and less solar energy is received than further south. But the high latitude also ensures very long summer days, as the sun stays above the horizon nearly 20 hours each day, with only around 6 hours of daylight occurring in the dark winters, depending on latitude. The areas of the taiga inside the Arctic Circle have midnight sun in mid-summer and polar night in mid-winter.
The taiga experiences relatively low precipitation throughout the year. Snow may remain on the ground for as long as nine months in the northernmost extensions of the taiga.
Much of the area currently classified as taiga was recently glaciated. As the glaciers receded, they left depressions in the topography that have since filled with water, creating lakes and bogs (especially muskeg soil), found throughout the taiga.
Much of the area currently classified as taiga was recently glaciated. As the glaciers receded, they left depressions in the topography that have since filled with water, creating lakes and bogs (especially muskeg soil), found throughout the taiga.
The forests of the taiga are largely coniferous, dominated by larch, spruce, fir, and pine.
Taigas have some small-leaved deciduous trees like birch, alder, willow, and poplar; mostly in areas escaping the most extreme winter cold.
There are two major types of taiga. The southern part is the closed canopy forest, consisting of many closely-spaced trees with mossy ground cover. In clearings in the forest, shrubs and wildflowers are common, such as the fireweed. The other type is the lichen woodland or sparse taiga, with trees that are farther-spaced and lichen ground cover; the latter is common in the northernmost taiga
Evergreen species in the taiga (spruce, fir, and pine) have a number of adaptations specifically for survival in harsh taiga winters. Taiga trees tend to have shallow roots to take advantage of the thin soils, while many of them seasonally alter their biochemistry to make them more resistant to freezing, called "hardening". The narrow conical shape of northern conifers, and their downward-drooping limbs, also helps them shed snow.
Because the sun is low in the horizon for most of the year, it is difficult for plants to generate energy from photosynthesis. Pine, spruce and fir do not lose their leaves seasonally and are able to photosynthesize with their older leaves in late winter and spring when light is good but temperatures are still too low for new growth to commence. The adaptation of evergreen needles limits the water lost due to transpiration and their dark green color increases their absorption of sunlight. Although precipitation is not a limiting factor, the ground freezes during the winter months and plant roots are unable to absorb water, so desiccation can be a severe problem in late winter for evergreens.
The boreal forest, or taiga, supports a large range of animals. Canada's boreal forest includes 85 species of mammals, 130 species of fish, and an estimated 32,000 species of insects. Insects play a critical role as pollinators, decomposers and as a part of the food chain; many nesting birds rely on them for food. The cold winter and short summers make the taiga a challenging biome for reptiles and amphibians, which depend on environmental conditions to regulate their body temperatures, and there are only a few species in the boreal forest. Some hibernate underground in winter.
The taiga is home to a number of large herbivorous mammals, such as moose and reindeer/caribou. Some areas of the more southern closed boreal forest also have populations of other deer species such as the elk (wapiti) and roe deer. There is also a range of rodent species, including beaver, squirrel, mountain hare, snowshoe hare and vole. These species have evolved to survive the harsh winters in their native ranges. Some larger mammals, such as bears, eat heartily during the summer in order to gain weight, and then go into hibernation during the winter. Other animals have adapted layers of fur or feathers to insulate them from the cold.
A number of wildlife species that are threatened or endangered can be found in the Canadian boreal forest, including woodland caribou, American black bear, grizzly bear and wolverine.
Predatory birds (owls and eagles) and other smaller carnivores, including foxes and weasels, feed on the rodents live here. Larger carnivores, such as lynx and wolves, prey on the larger animals. Omnivores, such as bears and raccoons are fairly common, sometimes picking through human garbage.
More than 300 species of birds have their nesting grounds in the taiga. Of the 300 species of birds that summer in the taiga, only 30 stay for the winter. These are either carrion-feeding or large raptors that can take live mammal prey, including Golden Eagle, Rough-legged Buzzard, and Raven, or else seed-eating birds, including several species of grouse and crossbills.
Temperate Deciduous Forest
A temperate deciduous forest is a biome found in the eastern and western United States, Canada, central Mexico, southern South America, Europe, West Asia, China, Japan, North Korea, South Korea and parts of Russia. A temperate deciduous forest consists of trees that lose their leaves every year. Examples include oak, maple, beech, and elm.
Many well-known animals live in this kind of forest. Some examples are the Eastern Gray Squirrel, bears, beavers, foxes, deer, rats, snakes, mice, wolves, raccoons, and large birds of prey like red-tailed hawks. These animals have unique adaptations suited for seasonal life. For example, some rodents store up fat, then hibernate during cold winters. Birds include the bald eagle, nightingale, cardinals, hawks, and the snowy owl.
The plants of this biome must be very well adapted to survive in these conditions. For example, trees like the beech, white spruce, and the elm have leaves that absorb water and sunlight. The soaring branches do more than just provide shade for other creatures of this biome; they also provide nutrients necessary for the tree to live. Another example of adaptation: these trees shed their leaves in the winter. By shedding their leaves, they cannot transpire. Consequently, they are able to retain water for the winter. Plants also soak up nutrients from the soil. These plants shed their leaves in autumn.
The plants of this biome must be very well adapted to survive in these conditions. For example, trees like the beech, white spruce, and the elm have leaves that absorb water and sunlight. The soaring branches do more than just provide shade for other creatures of this biome; they also provide nutrients necessary for the tree to live. Another example of adaptation: these trees shed their leaves in the winter. By shedding their leaves, they cannot transpire. Consequently, they are able to retain water for the winter. Plants also soak up nutrients from the soil. These plants shed their leaves in autumn.
Many well-known animals live in this kind of forest. Some examples are the Eastern Gray Squirrel, bears, beavers, foxes, deer, rats, snakes, mice, wolves, raccoons, and large birds of prey like red-tailed hawks. These animals have unique adaptations suited for seasonal life. For example, some rodents store up fat, then hibernate during cold winters. Birds include the bald eagle, nightingale, cardinals, hawks, and the snowy owl.
The plants of this biome must be very well adapted to survive in these conditions. For example, trees like the beech, white spruce, and the elm have leaves that absorb water and sunlight. The soaring branches do more than just provide shade for other creatures of this biome; they also provide nutrients necessary for the tree to live. Another example of adaptation: these trees shed their leaves in the winter. By shedding their leaves, they cannot transpire. Consequently, they are able to retain water for the winter. Plants also soak up nutrients from the soil. These plants shed their leaves in autumn.
The plants of this biome must be very well adapted to survive in these conditions. For example, trees like the beech, white spruce, and the elm have leaves that absorb water and sunlight. The soaring branches do more than just provide shade for other creatures of this biome; they also provide nutrients necessary for the tree to live. Another example of adaptation: these trees shed their leaves in the winter. By shedding their leaves, they cannot transpire. Consequently, they are able to retain water for the winter. Plants also soak up nutrients from the soil. These plants shed their leaves in autumn.
Grassland Biome
Grasslands
Grasslands (also called greenswards) are areas where the vegetation is dominated by grasses and other herbaceous (non-woody) plants. Grasslands occur naturally on all continents except Antarctica.
Grassland vegetation can vary in height from very short, as in Chalk Downland where the vegetation may be less than (12 in) high, to quite tall, as in the case of North American tall grass prairie, South American grasslands and African savanna. Woody plants, shrubs or trees, may occur on some grasslands - forming savannas, scrubby grassland or semi-wooded grassland, such as the African savannas or the Iberian Dehesa. Such grasslands are sometimes referred to as wood-pasture or woodland.
Grasslands cover nearly fifty percent of the land surface of the continent of Africa. While grasslands in general support diverse wildlife, given the lack of hiding places for predators, the African Savanna regions support a much greater diversity in wildlife than do temperate grasslands.
The appearance of mountains in the western United States during the Miocene and Pliocene epochs, a period of some 25 million years, created a continental climate favorable to the evolution of grasslands. Existing forest biomes declined, and grasslands became much more widespread. Following the Pleistocene Ice Ages, grasslands expanded in range in the hotter, drier climates, and began to become the dominant land feature worldwide.
Grasslands are of vital importance for raising livestock for human consumption and for milk and other dairy products.
Grassland vegetation remains dominant in a particular area usually due to grazing, cutting, or natural or manmade fires, all discouraging colonization by and survival of tree and shrub seedlings. Some of the world's largest expanses of grassland are found in African savanna, and these are maintained by wild herbivores as well as by nomadic pastoralists and their cattle, sheep or goats.
Grasslands may occur naturally or as the result of human activity. Grasslands created and maintained by human activity are called anthropogenic grasslands. Hunting peoples around the world often set regular fires to maintain and extend grasslands, and prevent fire-intolerant trees and shrubs from taking hold. The tall grass prairies in the American Midwest may have been extended eastward into Illinois, Indiana, and Ohio by human agency. Much grassland in northwest Europe developed after the Neolithic Period, when people gradually cleared the forest to create areas for raising their livestock.
Tropical and subtropical grasslands
These grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome. Notable tropical and subtropical grasslands include the Llanos grasslands of northern South America.
Temperate grasslands
Mid-latitude grasslands, including the Prairie and Pacific Grasslands of North America, the Pampas of Argentina, Brazil and Uruguay, calcareous downland, and the steppes of Europe. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinoceroses, and wild horses. Carnivores like lions, wolves and cheetahs and leopards are also found in temperate grasslands. Other animals of this region include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds (both Old and New World varieties), grasshoppers, meadowlarks, sparrows, quails, hawks and hyenas.
Flooded grasslands
Grasslands that are flooded seasonally or year-round, like the Everglades of Florida or the Pantanal of Brazil, Bolivia and Paraguay. They are classified with flooded savannas as the flooded grasslands and savannas biome and occur mostly in the tropics and subtropics.
(Mountain) grasslands
High-altitude grasslands located on high mountain ranges around the world, like the Páramo of the Andes Mountains are part of the mountain grasslands and shrublands biome and also constitute tundra.
Tundra grasslands
Similar to mountain grasslands, polar arctic tundra can have grasses, but high soil moisture means that few tundras are grass-dominated today. However, during the Pleistocene ice ages, a polar grassland known as steppe-tundra occupied large areas of the Northern hemisphere. These are in the tundra biome.
Desert and xeric grasslands
Also called desert grasslands, this is composed of sparse grassland eco-regions located in the deserts and xeric shrublands biome.
Grasslands (also called greenswards) are areas where the vegetation is dominated by grasses and other herbaceous (non-woody) plants. Grasslands occur naturally on all continents except Antarctica.
Grassland vegetation can vary in height from very short, as in Chalk Downland where the vegetation may be less than (12 in) high, to quite tall, as in the case of North American tall grass prairie, South American grasslands and African savanna. Woody plants, shrubs or trees, may occur on some grasslands - forming savannas, scrubby grassland or semi-wooded grassland, such as the African savannas or the Iberian Dehesa. Such grasslands are sometimes referred to as wood-pasture or woodland.
Grasslands cover nearly fifty percent of the land surface of the continent of Africa. While grasslands in general support diverse wildlife, given the lack of hiding places for predators, the African Savanna regions support a much greater diversity in wildlife than do temperate grasslands.
The appearance of mountains in the western United States during the Miocene and Pliocene epochs, a period of some 25 million years, created a continental climate favorable to the evolution of grasslands. Existing forest biomes declined, and grasslands became much more widespread. Following the Pleistocene Ice Ages, grasslands expanded in range in the hotter, drier climates, and began to become the dominant land feature worldwide.
Grasslands are of vital importance for raising livestock for human consumption and for milk and other dairy products.
Grassland vegetation remains dominant in a particular area usually due to grazing, cutting, or natural or manmade fires, all discouraging colonization by and survival of tree and shrub seedlings. Some of the world's largest expanses of grassland are found in African savanna, and these are maintained by wild herbivores as well as by nomadic pastoralists and their cattle, sheep or goats.
Grasslands may occur naturally or as the result of human activity. Grasslands created and maintained by human activity are called anthropogenic grasslands. Hunting peoples around the world often set regular fires to maintain and extend grasslands, and prevent fire-intolerant trees and shrubs from taking hold. The tall grass prairies in the American Midwest may have been extended eastward into Illinois, Indiana, and Ohio by human agency. Much grassland in northwest Europe developed after the Neolithic Period, when people gradually cleared the forest to create areas for raising their livestock.
Tropical and subtropical grasslands
These grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome. Notable tropical and subtropical grasslands include the Llanos grasslands of northern South America.
Temperate grasslands
Mid-latitude grasslands, including the Prairie and Pacific Grasslands of North America, the Pampas of Argentina, Brazil and Uruguay, calcareous downland, and the steppes of Europe. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinoceroses, and wild horses. Carnivores like lions, wolves and cheetahs and leopards are also found in temperate grasslands. Other animals of this region include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds (both Old and New World varieties), grasshoppers, meadowlarks, sparrows, quails, hawks and hyenas.
Flooded grasslands
Grasslands that are flooded seasonally or year-round, like the Everglades of Florida or the Pantanal of Brazil, Bolivia and Paraguay. They are classified with flooded savannas as the flooded grasslands and savannas biome and occur mostly in the tropics and subtropics.
(Mountain) grasslands
High-altitude grasslands located on high mountain ranges around the world, like the Páramo of the Andes Mountains are part of the mountain grasslands and shrublands biome and also constitute tundra.
Tundra grasslands
Similar to mountain grasslands, polar arctic tundra can have grasses, but high soil moisture means that few tundras are grass-dominated today. However, during the Pleistocene ice ages, a polar grassland known as steppe-tundra occupied large areas of the Northern hemisphere. These are in the tundra biome.
Desert and xeric grasslands
Also called desert grasslands, this is composed of sparse grassland eco-regions located in the deserts and xeric shrublands biome.
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