Social sciences: geography
Grade 6
Climate and vegetation regions of the world
Module 9
The main biomes (vegetation regions)
- The 5 main biomes
- Vegetation across the world is divided into
five large biomes :
- The Forest Biome
- Tropical forests
- Temperate forests
- Deciduous forests
- Needle leaf forests
- Mediterranean forests (Sclerophyll bush)
- Savannah Biome
- Grasslands Biome
- Desert Biome
- Tundra and ice fields Biome
Remember this!
Human beings have altered or destroyed the original environment of many parts of the world.
2. Area division of the different biomes
| Main biomes of the world |
| Biome |
Area(million km
2
) |
Percentage |
| Forests |
52,3 |
40,1 |
| Savannah |
21,8 |
16,7 |
| Grasslands |
8,8 |
6,8 |
| Deserts |
33,8 |
25,9 |
| Tundra |
13,7 |
10,5 |
THE FOREST BIOME
- This biome is dominated by various tree species. In some forests the dense canopy of treetops grows so closely that sunlight cannot penetrate to the ground. In other areas the trees are further apart and sunlight can partially penetrate the tree canopy.
- The most important of these forests is the
tropical rainforest. These forests are close to the Equator (in the tropics) where it is hot all year round with a very high rainfall. Most of the trees in tropical rainforests are broadleaf, evergreen trees. Palms and tree ferns are also found here. Relatively few people live in tropical rainforests because of the dense vegetation, which makes it difficult to move about.
- In the
deciduous forests ,
oak, walnut, willow and poplar trees are found. They shed their leaves during the winter season while the
temperate evergreen forests are found in regions with rain throughout the year. Pine trees with their pine-cones, called coniferous trees, are found in these forests. Many different kinds of insects, reptiles, spiders and birds live in these forests. The deciduous and temperate forests are found mostly in the regions that are densely populated ((North America, Europe and Asia). Through the ages people have been dependent on these forests for shelter, food, wood for their houses, weapons and energy.
Activity 1:
To discuss the effect of dense populations on natural forests
[lo 1.1]
Discuss in your groups the effect of densely populated areas on natural forests and how nature can be protected. Write a brief report on the findings of your group.
- Needle leaf forests occur between 50 °N and 70 °S and are adapted to long, cold winters and short summers.
- The downward sloping leaves of these trees make provision for snow to slide off the leaves.
- The branches are supple; therefore the weight of the snow does not break them easily.
- Very thick bark protects the trunk against the low temperatures.
- The needle-like leaves also allow the snow to slide off easily and their small surfaces reduce the trees’ level of exposure to the cold winter winds.
- The needles are covered with a waxy layer that reduces evaporation.
Unfortunately uncontrolled mining methods such as opencast mining, drilling for oil and the establishment of infrastructures that include roads and towns or cities, have damaged this natural biome to a large extent.
