Influence of Climate on Biomes:

Introduction:1. The biome that I have studied is the Amazon Rainforest

biome.

2. The tropical climate has influenced the vegetation, soil and fauna of the region.

Vegetation:1. The high temperatures, high rainfall and 12 hours of daily

sunshine means Tropical Rainforest biomes are ideal for the growth of vegetation.

2. The region experiences an average temperature of about 27º along with high humidity levels, averaging between 77% and 88%.

3. It is estimated that a typical patch of rainforest measuring just 6 km² contains as many as 1,500 species of flowering plants and 750 species of tree.

4. The forest floor occupies the lowest 2 metres or so of the rainforest and, as only 1% of the sunlight reaches the ground, vegetation has adapted in order to survive.

5. Trees have developed a shallow root system because all the nutrients are close to the surface.

6. Buttress roots form an aboveground root system to increase the surface area from which trees can draw their nutrients.

7. The understorey reaches 2 to 20 metres above the forest floor and has vegetation made up of mainly vines and epiphytes which have large leaves to trap as much light as possible.

8. Lianas have their roots on the ground but climb high into the canopy layer to reach available sunlight by wrapping around trees for support.

9. The highest layer of forest vegetation is the emergent layer which contains the tallest trees in the forest, e.g. mahogany which is up to 70 metres high.

10. The tallest trees have small leathery leaves and waxy bark to cope with wind and sunshine.

Soil:1. Tropical red soils, or latosols, make up the zonal soil that has

developed beneath tropical rainforests.

2. The soil is a red/orange colour as a result of the laterisation process, a form of intense chemical weathering and leaching that occurs in hot climates.

3. The heavy rainfall washes the nutrients in the humus into the soil where it is taken up by shallow roots of the rapidly growing plants before it is washed too deeply into the soil, giving the rainforest a very short nutrient cycle.

4. The soil has a thin O-horizon due to intense bacterial which rapidly decomposes dead organic matter.

5. A study of the Amazon forest showed 99% of the nutrients in the soil are held in the root mats of the forest floor.

6. The high levels of iron oxide and aluminium oxide in the A-horizon, along with the laterisation, means the soil has a yellow/orange colour.

7. In many places latosols are so rich in aluminium that they are termed bauxite, and have to be mined and processed to get the aluminium out of them.

8. High temperatures can also bake the A-horizon, turning it into a hard brick-like soil called laterite, which cannot be cultivated.

9. The B-horizon can be up to 40 metres deep and is uniform in texture due to intense leaching in the high temperatures.

Fauna:1. Animals have adapted to the tropical climate indirectly, by

becoming tree living (arboreal).

2. Each forest layer has different animals, some of which can survive without ever having to touch the ground, and many have evolved camouflage in order to survive in the forest.

3. Frogs such as the Giant Leaf Frog have adapted to the forest environment by having green skin and a body with an irregularly shaped outline which makes them resemble a leaf.

4. The Brazilian Tree Sloth lives its life completely in the canopy and eats leaves.

5. It has adapted to this life by moving very slowly and having a very slow metabolism which enables it to survive on the low energy content of the leaves it eats.

6. The fur of the Tree Sloth is camouflaged to look green because it allows moss and lichen to grow on it.

7. The Tree Sloth has large eyes to see in the shady conditions of the forest and their paws have long hooked claws to allow them hang easily from the tree branches.

8. Other animals have also adapted to life in the trees, with animals who live in the canopy layer often being able to fly or jump from tree to tree.

9. The Spider Monkey has a prehensile tail that can curl around branches and give extra support as the animal moves amongst the trees.

10. Some animals such as the Sugar Glider, a type of possum, have flaps of skin between their front and hind legs to help them glide as they jump from tree to tree.