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_Biomes of The World _
By: Sara Williams
A biome, also known as life zones, consists of all plants, animals, and other
organisms, as well the physical environment in a particular area. A biome is
characterized by its plant life, climate, and location. The climate and
physical features determine the boundaries of a biome. A biome is made up of
many different ecosystems. The ecosystems tend to have the same pants and
animals as neighboring biomes around the boundaries. The major biomes are the
tundra, taiga, tropical rain forest, temperate forests, desert, grassland,
savanna, chaparral, and marine. Each biome has its own characteristics such
as the tundra. The tundra is a biome that is located in the Northern
Hemisphere of the world. It circles the North Pole and reaches down to the
taiga. The tundra has a very cold and harsh climate, especially in the
winters. The average winter temperatures is about -30°F and average summer
temperatures is roughly 37-54°F. The yearly amount of precipitation, which
includes melting snow, averages to about 6 to 10 inches. With these conditions
it makes for a short growing season of about 50-60 days. In some parts it can
be up to 180 days. This is only found in the more southern part of the tundra.
Another aspect of the tundra includes the vegetation that is found there and
the adaptations that have been made. The tundra is known for its cold
temperatures, but also its limited plant species. The growth of the
vegetation is primarily low to the ground and the biomass of plants is
concentrated in the roots. Here the plants reproduce more likely by division
and building than by flower pollination. Some of that growthforms that you
will find in the tundra include tussock, mats or cushion plants, rosettes, and
dwarf shrubs. Other examples of plants include lichens, mosses, sedges,
perennial forbs, dwarfed shrubs (heaths, birches, and willows), cotton grass,
liverworts, and 400 varieties of flowers. Tundra plants over the years adapted
to sweeping winds and disturbances of the soil. Another adaptation is that
they are short and cluster together to help endure the cold. Also they can
carry out photosynthesis at low temperatures and low light intensities. Plants
arent the only things that have had to adapt to the conditions, animals have
had to as well. Animals of the tundra have had to adapt to the long cold
winters and to having to raise their young quickly in the summer. Some other
adaptations of animals include thick insulating cover of feathers or fur;
large, compact bodies; pelage and plumage that turns white in the winter and
brown in the summer; the ability to accumulate thick deposits of fat during
the short growing season; hibernation; and migration. Some of the animals that
are found living in the tundra are lemmings, voles, caribou, artic hares,
squirrels, artic foxes, wolves, polar bear, ravens, snow buntings, falcons,
loons, ravens, sandpipers, terns, snow birds, mosquitoes, flies, moths,
grasshoppers, black flies, artic bumble bees, cod, flatfish, salmon, and
trout. Some of these animals are shared with other neighboring biomes but some
are only home to the tundra. The tundra is the simplest biome in terms of
species composition and food chain. The neighboring biome of the tundra is the
boreal forest (taiga). The taiga is a biome that reaches completely across
Canada and into the interior of Alaska. The climate is like the tundra in the
sense that it has long, severe winters that last up to 6 months. The summers
on the other hand are rather short. Although compared to the tundra, the
growing season is longer and warmer. The mean annual precipitation is 15 to 20
inches. Throughout the year the temperatures range from the lows in the winter
to highs in the summer. The taiga is also found to be very humid. The kinds of
plants that have adapted to this kind of climate include needle leaf,
coniferous trees such as spruce, fir, pine, and larch or tamarack. These trees
are the dominant plant species of the taiga. Some other types are alder,
birch, and aspen. Trees of the taiga are typically shallow rooted due to the
poor soils, the rocky conditions, and the discontinuous permafrost. The plants
living in this biome have had to make adaptations. These adaptations consist
of needle-like leaves to prevent water loss, conical shape to help shed snow
that may weight down and break the branches, and their evergreen color to help
photosynthesis to occur. The other types of life found in the forest are that
of animals. Some examples of those are lynx, weasel family, snowshoe varying
hare, red squirrel, lemmings, voles, elk or wapiti, moose, beaver, wood
warblers, finches, sparrows, and ravens. These are just a few of the animals
found in this biome. Another biome of the world is the chaparral. Its found
in only 5 places in the world. They are Southern California, South Africa,
Western Australia, Southern Europe, and South America. It has mild rainy
winters and hot dry summers. The annual rainfall is about 12-24 inches. In
this climate, vegetation such as tall bushes and small trees with dark green
leaves exist. Most plants have small, hard leaves that do not fall off in the
winter. The leaves are covered with a hard waxy covering, which helps them to
burn in hot fire more easily. An adaptation that many plants have in the
chaparral is they have an adaptation to fire, which means they actually need
fire as a part of their lives. When a forest fire occurs it my kill of more
branches but new sprouts and plants grow from the burnt forest. The varieties
of the flora are California Lilacs, Scrub Oak, Toyon or Christmas Holly,
Mountain Mahogany, Bush Poppy, Holly-leaved Cherry, Redberry, and Sugarbush.
This is just some of the vegetation. Some of the animals consist of squirrels,
rabbits, coyotes, mule deer, opossums, raccoons, skunks, foxes, bobcats,
rattlesnakes, lizards, frogs, vultures, hawks, golden eagles, peregrine
falcons, and condors. Each of these has made unique adaptations to live in
this biome. An additional main biome is the tropical rainforest. The tropical
rain forest is one of the earths most distinctive biomes. There are 3 types
are subtropical, monsoon, and equatorial. The climate has mostly warm, humid
temperatures. The annual rainfall is approximately 20-30 inches. Depending on
the time of year the temperatures vary. Summer temperatures are about 95-100°
F and winter temperatures are about 70-80° F. Most tropical rain forests are
located between 10 degree N and 10 degrees S latitude. This makes the climates
for that vegetation found there suitable. If you were to explore the entire
rainforests youd find approximately 1500 species of flowering plants and 750
species of trees. The rain forest contains over 50% of worlds population in
plants and animals. It covers roughly 5 billion acres of land. There are 3
layers of trees that can be found there. The first and most top layer is the
emergent, which are widely spaced trees 100-120 ft tall with canopies above
the general canopy of the forest. The second, middle layer is a closed canopy
of 80-foot trees. Here light is available to this layer, but blocks out the
light of lower lays. The third layer is a closed canopy of 60-foot trees. This
is where little air movement occurs and there is high humidity. Another lower
layer is the shrub/sapling layer. In this place of the forest less than 3% of
light reaches here. Then there is the ground layer where there is spare plant
growth that receives around 1% of light reaches. Some of the characteristics
of the tropical trees involve Buttresses (woody flanges at the base of the
trunk), large leaves (that help to intercept light), drip tips on the leaves
(helps drainage of precipitation of the leaf), thin bark (often 1-2 mm thick),
and development of fruits and flowers from the base of the tree. One kind of
flora that has adapted to the rain forests is epiphytes. It grows up the
branches of tall canopy trees to reach light. The animals adaptations of the
rain forest are that they are highly diverse, have arboreal adaptations for
climbing in the tree, they have bright colors and sharp patterns, loud
vocalizations, diet heavy on fruits, and have camouflage. The types of animals
found there are primates, snakes, lizards, birds, insects, and cats. These are
just some characteristics of the rain forest. The next biome is the temperate
forests. These are to be found in eastern North America, northeastern Asia,
and western and central Europe. Here the seasons are very well defined. The
growing seasons last usually from about 140-200 days, much longer then most
other biomes. The yearly average rainfall is about 75-150 cm depending on the
area you are in. Here the temperatures change according to the seasons. Since
this climate has such a long growing season you will find many plants. In
temperate forests there are about 3-4 tree species per square kilometer. Trees
are distinguished my broad leaves that are lost annually. Examples of there
are oak, hickory, beech, hemlock, maple, basswood, cottonwood, elm, willow,
spring-flowering herbs, shrubs, and mosses. Here the soil is rich in organics,
which is great for the vegetation. Just like the rain forest the temperate
forest has a canopy. The canopy is moderately dense and allows light to
penetrate through. Most of the current forests are probably not the original
forest because many forests were logged off and replanted. Additional biomes
are the savannas and grasslands. They are located in Russia, central US,
Africa, South America, and Australia. They have a continental climate, which
means that have the climate of the interior of the continent. Here there it is
about 10-20 inches of precipitation a year. Its usually warm to hot in the
summer. In the tropical savanna the mean monthly temperatures are at or above
64° F. In both biomes they have similar vegetation. They have continuous cover
of perennial grasses and some woody vegetation. They may also have a canopy of
drought-resistant, fire-resistant, or browse-resistant trees. These are some
of the vegetations adaptations. Some of the animals found in these regions are
ground squirrels, prairie dogs, zebra, rhinos, giraffes, elephants, warthogs,
buffalo, coyote, and badgers. The temperate grasslands are lower in diversity
of animals compared to tropical grasslands and savannas. Most of the
herbivorous mammals of open savannas are herd animals. Also termites are
abundant in tropical savannas. The next and driest biome is the desert. The
desert is located in US, Northern Africa, Australia, and southwestern Asia. It
is gets less then 10 inches of rain per year. The potential evaporation
exceeds precipitation in the annual water budget causing a problem of drought
in some areas. The rainfall is highly localized in the desert. Temperatures
often exceed 100° F in summer. At night the temperatures dip by about 20-30
degrees making the desert nights cold . The desert is full of adaptive
plants. The plants found in the desert are primarily shrubs as the growthform
of deserts. There maybe evergreen or deciduous trees in certain areas. Its
typical for the plants to have small leaves. Frequently the vegetation has
spines or thorns as an adaptation from animals such as the cactus. Most
vegetation of the desert has shallow but extensive root systems. They are used
to absorb rainwater out past the canopy of the plant. Between shrubs the
ground is bare because the roots release toxins to keep away competition for
growth. Plants are able to store water and to adapt to long periods without
much precipitation. Just like the plants, the animals are some of the most
adaptive. Some animal adaptations are nocturnal feeding; morphological
adaptations, which is the ability to radiate body heat and colors that are
able to reflect sunlight; and physiological adaptations, which is the absence
of sweat glands, dormancy during summer, concentration of urine. Examples of
desert animals are many reptile, snakes, lizards, toads, and birds. The last
biome is the Marine zone. This includes all salt and freshwater aquatic areas.
The ocean takes up about 70% of the worlds area. Lakes and other fresh water
areas are found covering the globe. Ocean stays relatively the same
temperature due to the large area it covers. Aquatic zones affect the climates
of other zones. Since the climate is fairly limited the growth of vegetation
is as well. The flora involves cattails, algae, lily pads, grasses, sedges,
and seaweed. Other surround vegetation that maybe found in bogs, marshes or
ponds include grasses, trees, mosses, and shrubs. Plants are more greatly
found in marches and other wetlands. Animals are a very large part of the
marine zone. A few of the saltwater animals include sharks, fish, eels, clams,
worms, crabs, whales, dolphins, many invertebrates, sea stars, and mussels.
Some freshwater animals are trout, bluegills, sunfish, snakes, turtles, frogs,
insects, and snails. The different zones with in the ocean are intertidal,
peliagic, abyssal, benthic, coral reef, and estuaries. Some freshwater
habitats include marches, lakes, rivers, ponds, wetlands, and bogs. All the
biomes of the world have climates, plants, and animals all their own.
Traveling through each zone you can pick out the similar adaptations of each
plant and animal. Biomes are unique to their location, each one of great
importance to the world.
_Bibliography _
Bibliography 1. Biomes, http://ths.sps.lane.edu/biomes 2. Aquatic Biomes,
http://redbaron.bishops.ntc.nf.ca/wells/biomes/html/aquatic.htm 3. Biomes,
SLW, October 1996, http://runet.edu/~swoodwar/CLASSES/GEOG235/biomes
4. Chaparral, http://www.csun.edu/csc24235/hairach.html 5. Northern Coniferous
Forest,
http://www.uwsp.edu/acaddept/geog/faculty/ritter/geog101/biomes_northern_forest
.html 6. The World of Biology, 4th ed., Davis, Solomon, Berg; Saunders College
Publishing, Ó1994.
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