Deserts
Deserts cover about one fifth (20 percent) of the earth's land area. The desert is a
harsh environment with very little rainfall and extreme temperatures; a desert is
defined as a region that gets less than ten inches of precipitation per year. Because of
these dry conditions, there is limited plant and animal life in deserts. Desert plants
(like cacti) are not abundant; neither is animal life.
Some deserts get both very hot (during the day) and very cold (during the night, when
temperatures can drop well below freezing). Some deserts, however, are always cold
(for example, the Gobi Desert in Asia, and the desert on the continent of Antarctica).
Different animals live in the different types of deserts. Animals that live in the desert
have adaptations to cope with the lack of water, the extreme temperatures, and the
shortage of food. To avoid daytime heat, many desert animals are nocturnal; they
burrow beneath the surface or hide in the shade during the day, emerging at night to
eat. Many desert animals do not have to drink at all; they get all the water they need
from their food. Most desert animals are small.
Desert Extremes: The biggest desert is northern Africa's Sahara Desert; it covers roughly 3,500,000 square miles
(9,065,000 square kilometers). The driest deserts are the Atacama desert of northern Chile, South America, and the Lut
Desert in eastern Iran; these extreme deserts get less than half an inch (about 1 centimeter) of precipitation each year and it is from condensed fog, and not from rain.
Tundra
The tundra is a cold, treeless area; it is the coldest biome. The tundra is characterized
by very low temperatures, very little precipitation (rain or snow), a short growing
season, few nutrients, and low biological diversity. The word tundra comes from the
Finnish word tunturia, which means "treeless plain."
There are two types of tundras, Arctic tundras and alpine tundras.
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Arctic tundras are frozen, windy, desert-like plains in the Arctic that are
dotted with bogs and ponds. Permafrost (a layer of frozen subsoil) covers the
ground, so there is very little drainage of water. The short growing season lasts
for only 50 to 60 days. Arctic tundras are located in the far north of Greenland,
Alaska, Canada, Europe, and Russia. Some animals of the Arctic tundra
include:
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Mammals - Arctic foxes, Arctic hares, caribou, ermine, lemmings, musk oxen, polar bears, porcupines,
Arctic shrews, squirrels, voles, weasels, wolves
Birds - Arctic loons, snowy owls, falcons, ptarmigans, ravens, snow buntings, snow birds, snow geese,
sandpipers, Arctic terns, tundra swans, many species of gulls
Fish - cod, flatfish, salmon, trout
Insects - Arctic bumblebees, blackflies, flies, grasshoppers, mosquitoes, and moths.
Alpine tundras are located high in mountains worldwide, above the tree line.
The growing season is about 180 days, and nighttime temperatures are usually
below freezing. The soil is well-drained (unlike the Arctic tundra). Some animals
of the alpine tundra include:
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Mammals - elk, marmots, mountain goats, pikas, sheep
Birds - grouse-like birds
Insects - beetles, butterflies, grasshoppers, and springtails.
Taiga (coniferous forest)
A taiga, also called a boreal forest or northern coniferous forest, is a cold woodland
or forest. This biome span the northern parts of North America, Europe, and Asia.
Taigas are generally located south of tundras and north of temperate deciduous
forests and temperate grasslands. The taiga is the largest land biome on Earth,
covering about 50 million acres of land (20 million hectares); this is about 17% of the
Earth's land area. Taiga is a Russian word for marshy pine forest.
The taiga is characterized by a cold, harsh climate, a low rate of precipitation (snow
and rain), and short growing season. There are two types of taigas: open woodlands
with widely spaced trees, and dense forests whose floor is generally in shade.
Taigas are relatively low in animal diversity because of the harsh winters. Some taiga
animals are able to cope with the cold winter environment, but many migrate south to
warmer climates during the winter and others go into hibernation.
Temperate deciduous forest
Temperate deciduous forests are forests in cool, rainy areas; they have trees that lose
their leaves in Fall and regrow them in Spring. Temperate deciduous forests are found
in the middle latitudes around the globe and have four distinct seasons: Spring,
Summer, Fall, and Winter. In the Northern Hemisphere, these forests are found in
North America, Europe, and Asia. In the Southern Hemisphere, there are smaller
areas of these forests, in South America, Africa, and Australia. The growing season in
these forests is about 6 months long.
Temperature and Precipitation: The average temperature in temperate deciduous
forests is roughly 75°F (24°C) but gets as high as 86°F (30°C), depending on the altitude
of the forest. Forests higher in the mountains are colder. Deciduous forests receive
from 2 to 5 feet (0.5-1.5 m) of precipitation (both rain and snow) each year. Humidity in
these forests is high, from 60% to 80%.
Fall Colors: In the Fall, the number of hours of daylight decreases. This causes some
plants and trees (called deciduous) to stop producing chlorophyll (a green pigment that
converts sunlight into chemical energy) and eventually lose their leaves. During this
time, these leaves turn brilliant colors, ranging from red to orange to yellow to brown.
Soil: The soil in the deciduous forests is quite fertile, since it is often enriched with
falling leaves, twigs, logs, and dead organisms.
Layers of the Temperate Deciduous Forest: There are five layers (also called zones or
strata) in the temperate deciduous forest. These include the:
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Tree stratum, the tallest layer, 60 -100 feet high, with large oak, maple, beech, chestnut, hickory, elm,
basswood, linden, walnut, or sweet gum trees.
Small tree or sapling layer - short tree species and young trees.
Shrub layer - shrubs like rhododendrons, azaleas, mountain laurels, and huckleberries.
Herb layer - short plants.
Ground layer - lichens, clubmosses, and true mosses.
Grasslands
What is a Grassland? A grassland is a grassy, windy, partly-dry biome, a sea of grass.
Almost one-fourth of the Earth's land area is grassland. In many areas, grasslands
separate forests from deserts. Deep-rooted grasses dominate the flora in a grassland;
there are very few trees and shrubs in a grassland, less than one tree per acre. There
are many different words for grassland environments around the world, including
savannas, pampas, campos, plains, steppes, prairies and veldts.
There are two types of grasslands, including:
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Tropical grassland - hot all year with wet seasons that bring torrential rains.
Located between the Tropic of Cancer and the Tropic of Capricorn,
sometimes called savannas.
Temperate grasslands - hot summers and cold winters. The evaporation rate is
high, so little rain makes it into the rich soil. Located north of the Tropic of
Cancer and south of the Tropic of Capricorn.
Animal Adaptations: The animals that live in grasslands have adapted to dry, windy
conditions. There are grazing animals (that eat the grass), burrowing animals, and their
predators; insects are abundant. A moderate of level species diversity exists on a
grassland.
Where are Grasslands? Grasslands are located in North America's interior
(called prairies), in southeastern South America (Argentina's pampas and the campos
of Uruguay and Brazil), in Eurasia (the Eurasian steppe in Mongolia and parts of the
former Soviet Union), in Africa (the semi-arid steppes of the Sahel of north-central
Africa and the wetter grasslands, veldts, of East Africa and Madagascar), and in
Australia and New Zealand (called rangelands).
Animals that Live in Grasslands: Many animals live in grasslands, from invertebrates
(like grasshoppers and beetles) to large mammals (like antelopes and bison). The
different grasslands of the world support different populations of animals.
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Africa - aardvark, African wild cat, African elephant, many antelopes, baboon, buffalo, Cape hunting
dog, cheetah, giraffe, gnu, hartebeest, hippopotamus, hyena, impala, jackals,
kudu, leopard, lion, meerkat, mongoose, oryx, ostrich, red-billed oxpecker,rhinoceros, vulture, wildebeest, zebra,
and many other animals.
Australia - dingo, emu, kangaroo, wallaby, wombat, and many other animals. Many non-native animals have
been introduced, including the camel, donkey, goat, horse, rabbit, and sheep.
North America - American toad, badger, black-footed ferret, bison, black-tailed jack rabbit, bumble bee,
burrowing owl, California condor, carrion beetle, common snipe, coyote, deer, dragonfly, eagles, eastern
cottontail, elk, ferruginous hawk, fox snake, golden owl, gopher snake, grasshopper, gray wolf, ground squirrels,
killdeer, lady beetle, larks, long-billled curlew, meadow vole, monarch butterfly, northern grasshopper
mouse, prairie chicken, prairie dog, prairie rattlesnake, prairie skink, pronghorn antelope, red fox,red-tailed
hawk, shrew, skunk, stink bug, tiger beetle, western meadowlark, western tiger swallowtail, white-tailed jack
rabbit, and many other animals.
South America - armadillo, opossum, fox, jaguar, llama, puma, rhea, tapir, many rodents, and many other
animals.
Eurasia - golden pheasant, leopard gecko, snow leopard, vole, and many other animals.
Rainforest
Rainforests are very dense, warm, wet forests. They are havens for millions of plants
and animals. Rainforests are extremely important in the ecology of the Earth. The
plants of the rainforest generate much of the Earth's oxygen. These plants are also
very important to people in other ways; many are used in new drugs that fight disease
and illness.
Where are Rainforests? Tropical rainforests are located in a band around the equator,
mostly in the area between the Tropic of Cancer (23.5° N latitude) and the Tropic of
Capricorn (23.5° S latitude). This 3,000 mile (4800 km) wide band is called the "tropics."
Tropical rainforests are found in South America, West Africa, Australia, southern
India, and Southeast Asia.
Strata of the Rainforest
Different animals and plants live in different parts of the rainforest. Scientists divide
the rainforest into strata (zones) based on the living environment. Starting at the top,
the strata are:
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EMERGENTS: Giant trees that are much higher than the average canopy height. It houses many birds and
insects.
CANOPY: The upper parts of the trees. This leafy environment is full of life in a tropical rainforest and includes:
insects, birds, reptiles, mammals, and more.
UNDERSTORY: A dark, cool environment under the leaves but over the ground.
FOREST FLOOR: Teeming with animal life, especially insects. The largest animals in the rainforest generally live
here.
Animals that Live in Rainforests: Ridiculously huge numbers of animals live in
rainforests, including microscopic animals, invertebrates (like insects and worms), fish,
reptiles, amphibians, birds, and mammals. The different rainforests of the world
support different populations of animals. A few animals from each rainforest are
listed below:
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South America o insects (morpho butterfly, Julia butterfly, Monarch butterfly, and millions of other insects)
o mammals (jaguar, ocelot, didelphid opossums, sloth, howler monkey, spider monkey, capybara, many
bats, marmosets, procyonids, peccaries)
o birds (quetzal, macaw, tinamous, curassows, hoatzins, hummingbirds, eagles, ovenbirds, antbirds,
flycatchers, puffbirds,toucans, jacamars, tanagers, tapirs, troupials, honeycreepers, cardinal
grosbeaks, xenops)
o reptiles (anaconda, caiman, iguanas, lizards, microteiid lizards, boas, and coral snakes), amphibians
(poison arrow frog, etc.)
o fish (electric eel, piranha), and millions of other animals.
Australia o mammals (tree kangaroo, rat kangaroo, yellow-footed Antechinus, Giant White-tailed Uromys,
opossums, bandicoot, echidna,duck-billed platypus, sugar glider, red legged pademelon)
birds (cassowary, brolga, emerald dove, orange-footed scrubfowl, Australian brush-turkey, sarus crane,
gray goshawk, wompoo fruit dove, topknot pigeon, Australian king parrot, laughing kookaburra, lesser
sooty owl, fernwren, barred cuckoo-shrike, golden whistler, etc.)
o reptiles (frilled lizard, carpet python, Green Tree Snake, Spotted Tree Monitor, Eastern Water Dragon,
Boyd's Forest Dragon, Northern Leaf Tailed Gecko)
o insects (Ulysses butterfly, Zodiac Moth, Union Jack butterfly, Regent skipper, Birdwing Butterfly)
o amphibians (Giant Tree frog, Striped marsh frog, Northern Barred frog, Dainty Green Tree frog), and
millions of other animals.
Southeast Asia o mammals (tarsiers, orangutans, Siamangs, gibbons, colobine monkeys, tigers, tree shrews, binturong,
moonrats, most flying foxes, colugos, bamboo rats, Oriental dormice)
o birds (tree swifts, leafbirds, fairy bluebirds, fantails, whistlers, flowerpeckers, wood swallows)
o insects (Queen Alexandra's Birdwing butterfly, Goliath Birdwing butterfly, Saturn Butterfly), and
millions of other animals.
West Africa o mammals (antelopes, bonobo, chimpanzee, gorilla, Mandrill, scaly-tailed squirrels, otter shrews,
duikers, okapi, hippopotamus, Cercopithecus monkeys, bushbabies, pygmy hippo, duiker)
o birds (Congo peafowl, African Gray Parrot) and millions of other animals.
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