(a) Describe the characteristic features of the vegetation of the tropical rain forest. (b) Name two types of savanna found in Nigeria giving one example in...

(a) Characteristic features of the vegetation of the tropical rain forest

• Trees are very tall, close together and evergreen, with buttress roots supporting the tall trunks.
• The vegetation shows distinct layers (stratification): an emergent top layer, a continuous canopy, an under-canopy and a sparse shrub/ground layer.
• The dense canopy allows little light to reach the forest floor, so undergrowth is scanty.
• Plants are of many different species (high biodiversity) with broad leaves bearing drip-tips.
• Abundant epiphytes, climbers (lianas) and parasites grow on the trees.
• The climate supporting it is hot and wet all year with high rainfall and high humidity.

(b) Two types of savanna in Nigeria with a town in each

(Also acceptable: Sahel savanna - Maiduguri/Nguru; derived savanna - Enugu.)

(c) Adaptation of animals in arid habitats

(i) Adaptation to drought (water shortage)

1. They excrete concentrated urine and dry faeces to conserve water.
2. They obtain water from metabolic (oxidation) water and from the food they eat, and store fat (for example in the camel's hump) which yields water on oxidation.
3. They have thick, dry, impermeable skin or cuticle to reduce water loss by evaporation.

(ii) Adaptation to high temperatures

1. They are nocturnal, resting in burrows or shade during the hot day and being active at night when it is cool.
2. They have pale/light-coloured body surfaces that reflect heat, and long limbs raising the body above the hot ground.
3. They lose heat through large exposed surfaces (for example large ears) and by panting/sweating where possible.