World biomes

Bio geographical regions

The Earth can be divided into a series of bio geographical region or biomes,ecological communities where certain species of plant and animal coexist within particular climatic conditions.Within these broad classifications, other factor including soil richness ,altitude and humen activities such as urbanization , intensive agriculture  and deforestation of living species within each biome.

Wold biomes

·  Rainforest biome

·  Needleleaf biome

·  Broadleaf biome

·  Grassland biome

·  Tundra Biome

·  Mediterranean Biome

·  Mountain biome

·  Wetland biomes

·  Desert biome

·  Polar biome

          

 Readabout different types of Ecosystem:

 Read about Biodiversity:

Rainforest biome

Tropical Rainforest  Biome

        

         Tropical rainforest biome is the most complex and species-rich biome on the Earth. 80% of all world's biodiversity are found here.The reason for such amazing number of species is the ideal climatic conditions for plant growth: the warmth, and, more than anything - the moisture.This is compensated by extra high productivity - things decompose about 10 times quicker in tropical rainforests than in other biomes.The tropical rain forest is a forest of tall trees in a region of year-round warmth. An average of 50 to 260 inches (125 to 660 cm.) of rain falls yearly.

          Rain forests belong to the tropical wet climate group. The temperature in a rain forest rarely gets higher than 93 °F (34 °C) or drops below 68 °F (20 °C); average humidity is between 77 and 88%; rainfall is often more than 100 inches a year. There is usually a brief season of less rain. In monsoonal areas, there is a real dry season. Almost all rain forests lie near the equator. This is compensated by extra high productivity - things decompose about 10 times quicker in tropical rainforests than in other biomes.

          Rainforests now cover less than 6% of Earth's land surface. Scientists estimate that more than half of all the world's plant and animal species live in tropical rain forests. Tropical rainforests produce 40% of Earth's oxygen.

           About 1/4 of all the medicines we use come from rainforest plants. Curare comes from a tropical vine, and is used as an anesthetic and to relax muscles during surgery. Quinine, from the cinchona tree, is used to treat malaria. A person with lymphocytic leukemia has a 99% chance that the disease will go into remission because of the rosy periwinkle. More than 1,400 varieties of tropical plants are thought to be potential cures for cancer.

           All tropical rain forests resemble one another in some ways. Many of the trees have straight trunks that don't branch out for 100 feet or more. There is no sense in growing branches below the canopy where there is little light. The majority of the trees have smooth, thin bark because there is no need to protect the them from water loss and freezing temperatures. It also makes it difficult for epiphytes and plant parasites to get a hold on the trunks. The bark of different species is so similar that it is difficult to identify a tree by its bark. Many trees can only be identified by their flowers.

           The canopy layer typically blocks the sunlight, creating the dark forest floor where the vegetation is scarce enough that we can walk on the forest floor.If a tree falls and opens the canopy, a myriad of small pant species start growing on the forest floor.If large parts of the canopy are opened after say, a hurricane, the vegetation on the forest floor becomes so dense that we would not be able to walk there - it becomes a real jungle.

Animals

         Species such as lemurs and chameleons; and countless others such as Nile crocodiles, mongooses, tenrecs, and many species of bats, centipedes, frogs and lizards. Animals include Asian rhinos and Asian elephants, snow leopards and clouded leopards, crocodiles, bats, sun bears, black bears, bantengs, tarsiers and cobra snakes.A few species of marsupials such as wallabies and cuscus, but is more known for its bird-life with the famous birds of paradise, Victoria crowned pigeons and two species of cassowaries.

Plants

       Rainforest plants thrive extremely well in their environment, because every plant loves a lot of water, and rainforests are indeed very wet places.This means rainforests are thick and dense, full of plant life, and packed with different plants - it gets so crowded that the biggest competition is this of sunlight. Every plant tries therefore to reach high up to not to miss out on sunligh.Large trees grow tall and spread out their canopies and block the light from reaching the ground. Some extra tall trees, called emergents, grow through that canopy, even higher. Others, like vines climb on tree trunks to reach the sunlight high up.

       Orchids and epiphytes start growing high up in the trees when a bird drops a seed there. Shorter trees and other plants grow on the rainforest floor, where some light happens to reach the forest ground.When a high tree falls and opens up the canopy, smaller plants get a chance to start growing in the sunlight on the rainforest floor. Rainforest flora vary considerably between tropical and temperate rainforests; and between the rainforests on different continents. Tropical rainforest species are more numerous, while temperate rainforests have less layers and are more known for giant trees, mosses and epiphytes.

Temperate Rainforests Biome

        This is a small biome in terms of area covered. Temperate rainforests are found along coasts in temperate regions. The largest temperate rainforests are on the pacific coast in North America, stretching from Alaska to Oregon. Other temperate rainforests are found along the coast of Chile, the United Kingdom, Norway, Japan, New Zealand, and S. Australia. The largest temperate rainforests are on the pacific coast in North America, stretching from Alaska to Oregon. Tropical rainforests are generally found between 30°N and 30°S latitudes, covering 6-7% of the Earth’s land surface.A temperate rainforest grows in four main layers, with different trees, flow ers, and other plants in each layer.

         The trees that make up the temperate rainforest are huge, and their value as timber is proportionate to their size.  With forests elsewhere already cut, there is tremendous pressure to log in temperate rainforests.  Thus, timber cutting is the number one threat to these forests.  It should be noted that timbering can be very difficult here because of steep mountain slopes.

          At the end of summer plant and animal life is at its fullest. Animals have matured and plants are fertile and in full bloom. In the fall things change. Animals breed and start getting ready for the winter and plants stop growing. The temperature also begins to drop during the fall as cool, crisp air replaces the hot, humid air.

Animals

          Nocturnal animals, such as raccoons, flying squirrels, bats, and opossums, sleep in the trees during the day and have a full and active life at night. They wake up to forage or hunt for food. Other animals, like deer and black bears, are drowsy during the hot summer days and become more active during the cool nights. It is easy for predators and prey to hide from each other under the darkness of night. Animals that live during the day have to be trickier to hide themselves. Some animals live in burrows, trees, or the forest floor. Living in burrows is a safe refuge for small animals that need to hide from bigger animals.

Plants

          Dominating trees' oak, hickory, American chestnut trees, sugar maple, American beech, American basswood, birch, black cherry, magnolia, ash, and buckeye.

        The obvious element of climate in the temperate rain forest is precipitation.  At least 200 cm of it, perhaps up to 350 centimeters in warmer areas.  The precipitation can fall in the form of rain or snow, with snow becoming more likely at higher elevations.  The average annual temperature is above 0� C, largely influenced by the nearby ocean.  The warmest of the temperate rainforests may have average annual temperatures around 20� C.

These layers are:

1.The Top Layer (called the emergent layer)

       Huge trees rising high above the rest of the forest, therefore receiving the most sunlight.

2.The second layer (called the canopy)

      Tall trees growing close together so that their tops are close, forming a fairly continuous cover.

3.The third layer (called the understorey)

        Smaller trees, bushes, and plants such as ferns, form the understorey. Not much sunlight reaches here, because the canopy blocks the sun.

4. The fourth layer (called the forest floor)          

        Few plants grow on the forest floor because almost no sunlight reaches it. The leaves and plants that drop from the upper layers provide food and shelter for animals and insects that inhabit the forest floor.

Major biomes

Broadleaf biome

Tropical And Subtropical Dry Broadleaf Forest

      The tropical and subtropical dry broadleaf forest biome, also known as tropical dry forest, is located at tropical and subtropical latitudes. Though these forests occur in climates that are warm year-round, and may receive several hundred centimeters of rain per year, they have long dry seasons which last several months and vary with geographic location. These seasonal droughts have great impact on all living things in the forest.

     Deciduous trees predominate in most of these forests, and during the drought a leafless period occurs, which varies with species type. Because trees lose moisture through their leaves, the shedding of leaves allows trees such as teak and mountain ebony to conserve water during dry periods. The newly bare trees open up the canopy layer, enabling sunlight to reach ground level and facilitate the growth of thick underbrush. Trees on moister sites and those with access to ground water tend to be evergreen. Infertile sites also tend to support evergreen trees. Three tropical dry broadleaf forest ecoregions, the East Deccan dry evergreen forests, the Sri Lanka dry-zone dry evergreen forests, and the Southeastern Indochina dry evergreen forests, are characterized by evergreen trees.

     Though less biologically diverse than rainforests, tropical dry forests are home to a wide variety of wildlife including monkeys, deer, large cats, parrots, various rodents, and ground dwelling birds. Mammalian biomass tends to be higher in dry forests than in rain forests, especially in Asian and African dry forests. Many of these species display extraordinary adaptations to the difficult climate.

        This biome is alternately known as the tropical and subtropical dry forest biome or the tropical and subtropical deciduous forest biome. Locally some of these forests are also called monsoon forests, and they tend to merge into savannas

Temperate Broadleaf Deciduous Forest

         The Temperate Broadleaf Deciduous Forest (TBDF)--especially in eastern North America, where is remains most intact--is known for the turning of the colors of its leaves to brilliant reds, oranges, and golds in autumn. The shortening days of fall stimulate the plants to withdraw chlorophyll from their leaves, allowing a brief but beautiful display of other pigments before the leaves are shed completely and plants enter an extended period of dormancy.

Climate: Associated with warmer continental and humid subtropical climates (Dfa, Cfa, and--in Europe, Cfb). There is an approximately 6 month growing season. The 20 to 60 inches of precipitation is distributed evenly throughout the year. The non-growing season is due to temperature-induced drought during the cold winters.

Vegetation: Many of the same genera, previously part of an Arcto-Tertiary Geoflora, are common to all three of the disjunct northern hemisphere expressions of this biome. Included among these genera are Quercus (oak), Acer (maple), Fagus (beech), Castanea (chestnut), Carya (hickory), Ulmus (elm), Tilia (basswood or linden), Juglans (walnut), and Liquidamber (sweet gum). Different species of these genera occur on each continent.

Fauna: Characteristic members of the fauna are either mast-eaters (nut and acorn feeders) or omnivores. Mammals show adaptations to an arboreal life; a few hibernate during the winter months.

• North American herbivores include white-tail deer, gray squirrel, and chipmunk.
• Omnivores include raccoon, opossum, skunk, and black bear.

Carnivores have been largely eliminated through the deliberate effort of humans but should include timber wolves, mountain lions, and bobcats. The coyote, native to the western grasslands and deserts, has recently dispersed east and taken over the niche of its departed cousin, the timber wolf.

Major biomes

Grassland biome

TROPICAL GRASSLANDS

           Tropical grasslands, or savannas, are also the homes of primates in Africa and Asia; no savanna-living primates exist in South America. Tropical grasslands comprise a mixture of trees and grasses, the proportion of trees to grass varying directly with the rainfall. Areas of high seasonal rainfall support single-story woodlands of tall trees, while lush grasses form the ground vegetation.

           Tropical grasslands, or savannas, lie north and south of tropical rain forests that are on the equator. Some areas beyond savannas are hot deserts. Other savannas may be lined with mountains, dense forests, and seas. South America is home to several large savannas. An example of one of these savannas is the llanos, which means plains, located in the Orinoco River basin. The llanos is north of the Amazon forests and is shared in areas of Columbia and Venezuela. It is the size of France or Texas. Another large tropical grassland can be found south of the Amazon forest in the Brazilian Highlands, called campos. Other South American grasslands can be found in southeast Venezuela and southern Guyana.

          The worlds largest savannas can be found in Africa. The savanna takes up almost half of the continent. It stretches from the Atlantic coast of West Africa to the east across Sudan, and then goes south through east Africa. From Mozambique the savanna heads west and goes through Zambia and Angola, back to the Atlantic Ocean (Lambert, 30). Other savannas can be found in India's great Deccan Plateau, and in Australia, north of central deserts.

TEMPERATE GRASSLANDS

         The temperate grasslands are located in the mid-latitudes on planet Earth. These include the Prairies of North America, Pampas of South America and the Steppes of Eurasia. The temperate grasslands are further divided on the basis of their general characteristics. The best example of this is the Prairie biome of North America. In semi-arid regions - which are typically characterized by growth of short grass, the Prairies are known as Short-grass Prairies, while the same in regions with high rainfall - typically characterized by growth of tall grass, they are known as Tall-grass Prairies. This is just one of the numerous lesser known attributes of this grassland biome.

         Temperate grasslands are a division of a larger biome grouping of grasslands that includes tropical savannas.  Both biome types are characterized by a dominance of grasses, yet temperate grasslands differ significantly from savannas.  First unlike savannas that can have trees and shrubs scattered throughout, temperate grasslands have trees and shrubs absent.  Temperate grasslands are also found in less tropical ecosystems and thus have a larger temperate fluctuation during the year.  Temperatures in temperate grasslands can vary tremendously which has a large impact on growing seasons.  Generally they also have less rainfall. 

Regional Expressions: Temperate Grasslands are found throughout the globe, generally in the interiors of the continents and north or south of the tropic of cancer/Capricorn.  The following are the major regional expressions of grasslands recognized around the globe.

• Veldts of South Africa
• Puszta of Hungary
• Pampas of Argentina/Uruguay
• Steppes of Russia / China
• Plains and Prairies of North America

Minor Expressions: There are smaller local expressions of grasslands as well.  These include the following:

• Australian Outback
• Minnesota Cedar Creek Region

       Biodiversity: Grasslands (temperate) are dominated by one or a few species of grasses while there are several hundred other types of grasses and non-woody flowering plants that while less abundant make up a vital part of the species composition. There are many types of grass species that are dominant species in their own region.  Each species of grass grows better with varying temperatures / rainfall / and soil conditions.  Grasses are dominant (instead of trees) because of fire, drought and grazing by large herbivores. 

       Drought: Drought plays a large role in keeping trees from taking over the grasslands.  Some years receive less rain than others, just as certain seasons receive significantly less rain than others.  Trees generally can not stand the lack of water as easily as grasses and thus grasses remain dominant.

       Fire: Fire plays a big role in this biome, preserving biodiversity and keeping trees from overtaking the grasses.  Lightning from large storms rolling over the grasslands ignites large grass-fires.  These fires help certain plants by germinating seeds, clearing ground cover to allow rare plants a chance and by nourishing the soil with freshly burnt vegetation.

         Soil: The soil of the temperate grasslands is deep and dark.  The upper layers are the most fertile because of the buildup of many layers of dead branching stems and roots.  This organic mater on the surface and in the dead roots provide a great degree of nourishment for the living plants.

         Rainfall: Rainfall is generally less in temperate grasslands than in tropical savannas, although drought usually plays less of a roll effecting biodiversity than it does in savannas.  Rain usually falls in temperate grasslands in the late spring and early summer.  There is an average of 20 – 35 inches of rainfall a year.  The amount of rainfall however determines the height of grasses in the grassland.  For north America, this rainfall gradient helps to divide the temperate grasslands into tall grass prairies (in wetter areas) and short grass steppes (in dryer habitats).

         Environmental concerns: There is a great concern for remaining grasslands in temperate regions.  Because the soil in these areas is incredibly rich and the land is flat and treeless, most of this biome has been turned into farms or ranches.  The result of this overuse and consumption of the grassland by agricultural practices is a fragmentation of once large tracks of grassland.  Fragmentation decreases biodiversity (Theory of Island Biogeography).  Plowing of grasslands, combined with wind has lead to huge dust storms, such as those which created the Great Dust Bowl in the American Depression of the mid 1920s.  Finally, in dryer areas, overgrazing and salt build-up from irrigation of the land have turned these areas into near-wastelands.

          Floral Diversity: The most common grasses include blue gamma grass, buffalo grass, Johnson grass, and various sorts of wheat and burley.  Common flowers include types of asters, coneflowers, Solidagos (goldenrods), vetches, Indian blankets and sweet clovers.

          Fauna Diversity: In North America common animals include: bison, pronghorns, deer, mice, rabbits, grouse, badgers, skunks, meadowlarks, various  owls, garter snakes, rattle-snakes, red-tailed hawks and prairie dogs. 

Major biomes

Tundra Biome

        In the very cold places of the world, survival isn't easy. The soil is frozen, its top surface thawing only during summer, and no trees can grow. Yet plants and animals that are adapted for the harsh conditions thrive. This biome is called tundra. Most of the world's tundra is found in the north polar region. It is called Arctic tundra. There is a small amount of tundra on parts of Antarctica that are not covered with ice. Plus, tundra is found on high altitude mountains and is called alpine tundra.

       

          Permafrost is the term given to frozen soil. During the winter months, permafrost reaches the surface of the tundra. It is very cold during the winter, with temperatures reaching -60 degrees Fahrenheit (-51 degrees Celsius). Very few animals are active in these harsh conditions.

          In the summer time, the tundra changes. The Sun is out almost 24 hours a day, so the tundra starts to warm up. The permafrost melts at the surface, and plant life grows. However, the permafrost only disappears for a few inches below the surface. There isn't enough soil for trees to grow, so only small plants are found in the tundra.

            At the same time, a variety of animals come out to feast on the plants. Insects come to feed on the animals, and birds appear to enjoy the insects.

Characteristics of tundra include:

1. Extremely cold climate
2. Low biotic diversity
3. Simple vegetation structure
4. Limitation of drainage
5. Short season of growth and reproduction
6. Energy and nutrients in the form of dead organic material
7. Large population oscillations

Tundra is separated into two types:

Arctic tundra

                  Arctic tundra is located in the northern hemisphere, encircling the north pole and extending south to the coniferous forests of the taiga. The arctic is known for its cold, desert-like conditions. The growing season ranges from 50 to 60 days. The average winter temperature is -34° C (-30° F), but the average summer temperature is 3-12° C (37-54° F) which enables this biome to sustain life. Rainfall may vary in different regions of the arctic. Yearly precipitation, including melting snow, is 15 to 25 cm (6 to 10 inches). Soil is formed slowly. A layer of permanently frozen subsoil called permafrost exists, consisting mostly of gravel and finer material. When water saturates the upper surface, bogs and ponds may form, providing moisture for plants. There are no deep root systems in the vegetation of the arctic tundra, however, there are still a wide variety of plants that are able to resist the cold climate. There are about 1,700 kinds of plants in the arctic and subarctic, and these include:

• low shrubs, sedges, reindeer mosses, liverworts, and grasses
• 400 varieties of flowers
• crustose and foliose lichen

                      All of the plants are adapted to sweeping winds and disturbances of the soil. Plants are short and group together to resist the cold temperatures and are protected by the snow during the winter. They can carry out photosynthesis at low temperatures and low light intensities. The growing seasons are short and most plants reproduce by budding and division rather than sexually by flowering. The fauna in the arctic is also diverse:

• Herbivorous mammals: lemmings, voles, caribou
• Carnivorous mammals: arctic foxes, wolves, and polar bears
• Migratory birds: ravens, snow buntings, falcons, loons,
• Insects: mosquitoes, flies, moths, grasshoppers
• Fish: cod, flatfish, salmon, and trout

                   Animals are adapted to handle long, cold winters and to breed and raise young quickly in the summer. Animals such as mammals and birds also have additional insulation from fat. Many animals hibernate during the winter because food is not abundant. Another alternative is to migrate south in the winter, like birds do. Reptiles and amphibians are few or absent because of the extremely cold temperatures. Because of constant immigration and emigration, the population continually oscillates.

Alpine tundra

     Alpine tundra is located on mountains throughout the world at high altitude where trees cannot grow. The growing season is approximately 180 days. The nighttime temperature is usually below freezing. Unlike the arctic tundra, the soil in the alpine is well drained. The plants are very similar to those of the arctic ones and include:

• tussock grasses, dwarf trees, small-leafed shrubs, and heaths

Animals living in the alpine tundra are also well adapted:

• Mammals: pikas,, mountain goats, sheep
• Birds: grouselike birds
• Insects: springtails, grasshoppers ,beetles

 Major biomes

Mountain biome

          The mountain biome is harsh. The higher you climb the harsher it becomes due to the thinner atmosphere, high winds, and low temperatures. The type of flora and fauna change from the bottom to the top as the climate changes and the soil thins. The mountain biome has the largest variety of ecosystems and they will vary with the location of the mountain. I.e. the ecosystems of the Alps will not be the same as those of the Andes. The mountain biome is the most difficult to study as a whole because the fauna and flora varies from mountain range to mountain range.

            Mountains are usually found in groups called chains or ranges, although some stand alone. A mountain biome is very cold and windy. The higher the mountain, the colder and windier the environment. There is also less oxygen at high elevations.Several different types of plants and animals found in the mountain biome were left behind with the melting of the ice sheets as they retreated north at the end of the last ice age.

           The animals of this biome have adapted to the cold, the lack of oxygen, and the rugged landscape. They include the mountain goat, ibex (wild goat), sheep, mountain lion, puma, and yak. All of them are excellent climbers, which means they can move freely in the steep, rocky landscape. Types of plants vary depending on geographic location and altitude. Lower elevations are commonly covered by forests, while very high elevations are usually treeless.

               One common trait among the mountain biome fauna is that most of them are plant eaters. Such as the yak, mountain goat, the takin, ibex, chinchillas. Flora that can be found in most mountain biomes includes heather, lichens, coniferous tress, and chaparral.

                Mountains are a common sight on this planet. They make up one-fifth of the world's landscape, and provide homes to at least one-tenth of the world's people. Furthermore, 2 billion people depend on mountain ecosystems for most of their food, hydroelectricity, timber, and minerals. About 80 per cent of our planet's fresh water originates in the mountains. Since about half of the world's people are reliant upon mountains for fresh water, and in this time of increasing water scarcity, it is becoming increasingly important to protect the mountain biome.

                 All mountain ecosystems have one major characteristic in common--rapid changes in altitude, climate, soil, and vegetation over very short distances. Mountain ecosystems sport a high range of biodiversity, and are also a home to many of our planet's ethnic minorities. These cultures are sometimes 'protected' due to the challenging environment to produce a living, but others are not. More and more these indigenous people are being kicked out of their homes due to population and commercial growth, logging, and mining.

                 Rainfall varies greatly across the world's montane (mountain) biomes, ranging from very wet to very dry. However in all the biomes comes swift weather changes. For example, in just a few minutes a thunder storm can roll in when the sky was perfectly clear, and in just a few hours the temperatures can drop from extremely hot temperatures to temperatures that are below freezing.

                The world's mountains provide a home to several thousand different ethnic groups. The mountain people, which mainly consist of indigenous people, ethnic minorities, and refugees, have been able to cope with this harsh environment of the mountain ecosystem. They live as nomads, hunters, foragers, traders, small farmers, loggers, and miners, etc. They have been able to live off the land without widespread destruction and deforestation. Plant and animal species have been preserved by these people.

                The Himalayan Yew, a slow-growing conifer, is currently on the World Wildlife Fund's list of the ten most endangered animals. This plant can be found throughout Bhutan, Afghanistan, India, Nepal, Burma, and maybe China. Taxol, which is promising to be a drug which can help cure cancer, is present in both the Pacific and Himalayan varieties. Found in the world's highest mountain range, the Himalayan Yew is extremely rare because of heavy deforestation and harvesting for Taxol extraction, without replanting.

 Major biomes

Desert biome

              Deserts cover about one fifth of our planet, and are caused by extremely low rainfall over an area.  Theses biomes are nonetheless home to many plants and animals which have through the course of their evolution adapted to this dry environment.

              Hot and Dry Desert is, as you can tell from the name, hot and dry. Most Hot and Dry Deserts don't have very many plants. They do have some low down plants though. The only animals they have that can survive have the ability to burrow under ground. This is because they would not be able to live in the hot sun and heat. They only come out in the night when it is a little cooler.

              A cold desert is a desert that has snow in the winter instead of just dropping a few degrees in temperature like they would in a Hot and Dry Desert. It never gets warm enough for plants to grow. Just maybe a few grasses and mosses. The animals in Cold Deserts also have to burrow but in this case to keep warm, not cool. That is why you might find some of the same animals here as you would in the Hot and Dry Deserts.

              Deserts cover about one fifth of the Earth's land surface. Most Hot and Dry Deserts are near the Tropic of Cancer or the Tropic of Capricorn. Cold Deserts are near the Arctic part of the world.

               Hot and Dry Deserts temperature ranges from 20 to 25° C. The extreme maximum temperature for Hot Desert ranges from 43.5 to 49° C. Cold Deserts temperature in winter ranges from -2 to 4° C and in the summer 21 to 26° C a year.

              The precipitation in Hot and Dry Deserts and the precipitation in Cold Deserts is different. Hot and Dry Deserts usually have very little rainfall and/or concentrated rainfall in short periods between long rainless periods. This averages out to under 15 cm a year. Cold Deserts usually have lots of snow. They also have rain around spring. This averages out to 15 - 26 cm a year.

               Hot and Dry Deserts are warm throughout the fall and spring seasons and very hot during the summer. the winters usually have very little if any rainfall. Cold Deserts have quite a bit of snow during winter. The summer and the beginning of the spring are barely warm enough for a few lichens, grasses and mosses to grow.

              Hot and Dry Deserts vegetation is very rare. Plants are almost all ground-hugging shrubs and short woody trees. All of the leaves are replete (packed with nutrients). Some examples of these kinds of plant are Turpentine Bush, Prickly Pears, and Brittle Bush. For all of these plants to survive they have to have adaptations. Some of the adaptations in this case are the ability to store water for long periods of time and the ability to stand the hot weather.

                Hot and Dry Deserts animals include small nocturnal (only active at night) carnivores. There are also insects, arachnids, reptiles, and birds. Some examples of these animals are Borrowers, Mourning Wheatears, and Horned Vipers. Cold Deserts have animals like Antelope, Ground Squirrels, Jack Rabbits, and Kangaroo Rats.

Coastal and Cold desert

               Coastal deserts are found in areas that are moderately warm to cool, such as the Neotropic and Nearctic realm. The winters are usually cool and short, while the summers are long and warm  The soil is mostly sandy with a high alkaline content, it is also very porous, so rain seeps quite rapidly into the ground.  Most of the flora in the coastal desert features thick foliage, with  good water retention, and their roots are close to the surface of the ground in order to get enough water before it drains into the soil.

               Cold Desert's plants are scattered. In areas with little shade,about 10 percent of the ground is covered with plants. In some areas of sagebrush it reaches 85 percent. The height of scrub varies from 15 cm to 122 cm. All plants are either deciduous and more or less contain spiny leaves.

               Animals of the coastal desert include rough skinned amphibians, birds of prey, scavenger mammals reptiles and insects; most have adapted quite well to the climate, and again, they are largely nocturnal during the warmer months.

               Perhaps the strangest of all desert biomes is the cold desert, as our perception of the desert is usually associated with the heat of the sun.  But even if there is a moderately high amount of snow and rainfall during the wintertime, the soil is too heavy and alkaline.  Alluvial fans pull some of the salt through the porous soil, so plant life can survive, but then again, as with its arid counterparts, the cold desert offers less than ideal conditions for sustaining delicate plants and animals.

             Most of the animals in the cold desert are burrowers, even the carnivores and reptiles which even though cold-blooded, have made their homes in the cold desert.

            Deer and other larger herbivores are only found during the winter, as the supply of grass is more abundant during that period.

Semi Arid Deserts

             The major deserts of this type include the sagebrush of Utah, Montana and Great Basin. They also include the Nearctic realm (North America, Newfoundland, Greenland, Russia, Europe and northern Asia). The summers are moderately long and dry and like hot deserts, the winters normally bring low concentrations of rainfall. Summer temperatures usually average between 21 - 27° Centigrade. Temperature do not normally go above 38° Centigrade and evening temperatures are cool, at around 10° Centigrade. Cool nights help both plants and animals by reducing moisture loss from transpiration, sweating and breathing.

Animals that live in the Desert Biome

          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.

         Rarer, but important, are physiological adaptations such as aestivation (dormancy during summer), the absence of sweat glands, the concentration of urine, localized deposits of fat in tails or humps and salt glands to secrete salt without loosing fluids.

          Reptiles with their waterproof skin, production of uric acid instead of urine, hard-shelled eggs and ability to gain body heat directly from the sun and to retreat to shade or underground to avoid heat are exceptionally well adapted to dry lands and, not surprisingly, diverse there.

             There are relatively few large mammals in deserts because most are not capable of storing sufficient water and withstanding the heat. Deserts often provide little shelter from the sun for large animals. The dominant animals of warm deserts are non mammalian vertebrates, such as reptiles.

Desert plants

            Desert plants are uniquely adapted to life in a harsh and sometimes extreme environment. They often look unusual, and are sometimes quite beautiful. While desert plants are often greatly enjoyed in nature, they are also experiencing a growing popularity among landscapers. The same traits which allow desert plants to endure in the desert also make them suitable for low water gardening and xeriscaping. In hot, dry climates, desert plants can be used to assemble a striking and very water efficient garden. In cooler regions, desert plants sometimes do well in greenhouse conditions.

             Several traits set desert plants aside from others. The first is that they tend to be designed to store water, and to use water efficiently. Cacti and succulents, for example, both have dense flesh which is designed to store large amounts of water. Many plants also have long roots to reach deep into the water table for water. Other plants deal with hostile conditions by dying off during extreme weather, and reviving during the rainy season to briefly bloom and scatter seeds. During this small window of time, many visitors come to see the profusion of desert wildflowers.

              Many people associate cacti and succulents with the desert, but there are also a range of other plants. Desert wildflowers such as cliffrose, primrose, chuparose, brittlebush, sagebrush, sand verbena, yellow beeplant, and woolly daisies are common. There are also desert versions of familiar flowers like marigolds, lupines, poppies, sunflowers, chicory, mallow, dandelion,a and lily. During their blooming season, these wildflowers light up the desert with color.

           Deserts also host an assortment of trees and shrubs such as creosote bush, crucifixion bush, desert willow, elephant trees, mesquite, ponderosa pines, Joshua trees, and acacias. Many of these trees have minimal foliage, since water loss through leaves is undesirable for them. They may also be bedecked in thorns to discourage hungry animals, and they often have thick, fleshy trunks and branches.

Major biomes 

Polar biome

           Polar ice caps form because high-latitude regions receive less energy in the form of solar radiation from the sun than equatorial regions. This results in lower surface temperatures. Seasonal variations of the ice caps will take place due to varied solar energy absorption as the planet or moon revolves around the sun. Additionally, in geologic time scale, the ice caps may grow or shrink due to climate variation.

           A polar ice cap or polar ice sheet is a high-latitude region of a planet or moon that is covered in ice. This term is somewhat of a misnomer since an ice cap is less than 50,000 km² and is always over land: a larger area of ice is called an ice sheet. Polar ice caps do not have size, composition or geologic requirements of being over land, but they must be centered in the polar region.

           The Antarctic polar ice cap is a truly unique biome.The climate is very harsh, both on the land and in the water.The soil  is dry and rocky, with little vegetation.With a short growing season, cold temperatures, few plants exist.Thus, there is little decomposition and little organic matter in the soil which might help plant growth.This is the antithesis of the Temperate Deciduous Biome forests that have a lot of plant growth, lots of decomposition, and thus very rich soils that encourage further plant growth.

      

            The sun is very intense when there is no cloud cover because there is nothing to create shade.  Ozone depletion has been a problem in the Antarctic, and there is some thought that penguins and aquatic organisms near the surface of the water (ie. coral near Australia) may be affected by the increased level of UV light.

      

            The cold temperatures, combined with the high winds, leads to a significant windchill.  Even in peak summer the temperatures reached only + 5C.  In the winter it is so cold that it is almost impossible to travel here.  In 1999 a female doctor at a research base took care of her on starting cancer problems because planes could not fly in during the winter season.

             The land mass of the Earth's south pole, in Antarctica, is covered by the Antarctic ice sheet. It covers an area of almost 14 million km² and contains 30 million km³ of ice. Around 90% of the fresh water on the Earth's surface is held in this ice sheet. In addition, the West Antarctic Ice Sheet covers 3.2 million km² and the Ross Ice Shelf covers 0.5 million km².

             Earth's north pole is covered by floating pack ice (sea ice) over the Arctic Ocean. Portions of the ice that don't melt seasonally can get very thick, up to 3–4 meters thick over large areas, with ridges up to 20 meters thick. One-year ice is usually about a meter thick. The area covered by sea ice ranges between 9 and 12 million km².

Major biomes