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Part VIII : Introduction to the Earth

The Earth

Part IX : Climates and Biomes Index

Biomes : Questions

Weather and Climate
The Environment : The Atmosphere
The Greenhouse Effect
Is there life on Mars?
Hydrosphere, Lithosphere and Biosphere

Topic Chapters Index


Savannah montage © Shirley Burchill

The African Savannah 


Desert montage © Shirley Burchill 

The Sonoran Desert


Tropical Rain Forest montage © Shirley Burchill

Tropical Rain Forest


Tundra montage © Shirley Burchill

The Tundra


Coniferous forest montage © Shirley Burchill

The Coniferous Forest


Deciduous forest montage © Shirley Burchill

Temperate Deciduous Forest


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Living organisms prefer certain climatic conditions. This means that animals and plants are usually found only in regions that suit them. A tiger, for example, will be found in a region of high temperature and high humidity. Such a region of the biosphere is called a tropical rain forest. This is an example of a biome. A biome is a region of the Earth which has a characteristic combination of climatic conditions and living organisms.


The Savannah

Savannah, Kenya and Tanzania

Also called tropical grassland - where a tropical climate allows some trees and bushes to grow among the grasses and where zebras and elephants live.


The Desert

Sonoran Desert, Arizona

Most desert regions are always very hot during the daytime. There are different types of desert. A sandy desert, such as the Sahara, cannot support plant life. This is because sand is a poor soil. Water drains through it very quickly and it is easily moved by winds. Plant roots are unable to take a firm hold in sand. Water is very scarce but where it does occur the soil is able to support plant lift. These regions are called oases (sing. oasis).

Some deserts, such as the Sonoran desert in Arizona, are rocky areas with a thin top soil which is able to support plant life. The plants and animals which are found in these deserts are adapted to survive drought conditions. Cacti (sing. cactus) have roots which grow into the ground and radiate outwards over large distances in search of water. This is why cacti do not grow very close to each other in the desert; they are competing with each other for water. The cacti have a large volume inside a thick, spiky skin. They store water in their stems and the thick skin prevents too much of this water evaporating when the sun is out. Many desert animals hide in burrows or under rocks during the day and only come out to feed at night.


Fact File No.86

In the Tar Desert in Western India, the annual Rainfall between 1983 and 1988 was 1cm per year. Wells need to be dug 80m deep to reach the water table.


Tropical Rain Forest

Costa Rican Rainforests

In tropical rain forests the atmosphere is always hot and humid. Plants are very close together in these forests and they grow very tall as they compete with each other for sunlight. Not very much sunlight reaches the ground therefore you would not expect to find many plants at ground level. The humidity, however, would be ideal for the development of fungi and bacteria.

Inside a tropical rain forest you would not only feel hot and humid but you would smell the rotting vegetation on the forest floor. Most of the animals living in this type of forest would be able to reach the top of the tall trees. Birds would be plentiful as well as climbing animals such as monkeys and snakes. The air would be filled with flying insects.



Where the climate is cold and arid and only small plants can grow. Very few animals can survive because of the lack of liquid water. 


The Coniferous Forest

Can be in a cold, temperate, or mountain climate and is made up of evergreen trees such as fir and cedar trees. The ground is covered with is covered with needles and mosses.


Temperate Deciduous Forest

The spreading branches of the trees meet each other above the ground forming the canopy. If the trees in a forest are growing close together they will prevent a lot of the sunlight from reaching the forest floor. This means that only a few plants will be able to grow under the tree canopy. The forest will be dark and damp. You would expect to find many fungi (singular : fungus) growing on rotting wood and other decaying organisms.

If the trees are not growing so close together then more light will reach the forest floor. More plants will be able to grow. Those which grow close to the ground, such as mosses and ground ivy, make up the ground layer vegetation. The taller plants, such as bramble and dog's mercury, make up the field layer. This type of forest will be lighter and will not feel very damp.

Many of the forest animals will use the air to move from tree to tree. Birds and insects, some of them herbivores and some of them carnivores, will be plentiful. You might expect to find spiders' webs between the branches of some of the bushes. Snails and ants would be found in large numbers in the field layer. You could be lucky enough to see a deer or a squirrel.

In the Autumn the trees of a deciduous forest lose their leaves. These fall to the forest floor and make up the leaf litter. In the winter the forest looks bare. Many of the animals will have made a warm nest to sleep in through the cold weather. Other animals will spend much of their time scraping through the frozen soil to find food. Carnivores will find it harder to locate their prey. Many land habitats are effected by the seasons and the animals need to adapt their behaviour in order to survive through the cold weather.


The Prairie

Also called temperate grassland. Where a temperate climate allows grasses to grow and antelope or bison to live.


Buffalo on the Prairie © Paul Billiet


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