Question on Natural Vegetation : The function and usefulness of tropical rainforest

Evaluate the functions and usefulness of tropical rainforests. (8 marks)



Level 1 (0–2 marks)

• List functions briefly.
• No evaluation of usefulness.

Level 2 (3–5 marks)

• Describe functions briefly.
• Brief evaluation of usefulness.

Level 3 (6–8 marks)

• Explain functions in detail.
• Detailed evaluation of usefulness.
  

1. Rainforests are important to people because they make good water catchment areas.
   - They maintain the quantity of the water supply by playing a significant role in the water cycle through releasing water vapour into the atmosphere, thus encouraging cloud formation and rain.
   - The trees and leaves intercept water and protect the soil surface, thus allowing water to seep into the ground to be stored as groundwater.
   - They also support natural processes of filtering water which make water suitable for drinking and supporting life.
2. Rainforests are important to people because they maintain the quality of air.
   - The trees and plants replenish oxygen and remove carbon dioxide during photosynthesis and also help to regulate the temperature of the Earth.
3. Rainforests are important to people because they are a source of useful materials such as timber and chemicals for medicine.
4. Rainforests prevent floods that would have destroyed the environment.
   - They maintain soil nutrients because the roots of vegetation hold the soil particles together preventing them from being washed away by rain.
   - As the vegetation allows water to seep into the ground, they prevent soil erosion. This prevents rivers from being filled with sediment and overflowing, thus preventing floods.
5. Rainforests are important to the Earth’s ecosystem and the environment.
   - They form the habitat of the world’s flora and fauna. Without the rainforest ecosystem, many plants and animals are not able to survive.
6. Therefore, rainforests are very important in the following ways:
   • Maintaining the water supply
   • Maintaining nutrients in the soil
   • Replenishing oxygen and removing carbon dioxide
   • Habitat for flora and fauna
   • Protecting the coast
   • Natural treatment of waste water
   • Habitat
   • Recreation
   • Research and education
   
   Conclusion: Destruction of rainforests will eventually destroy the balanced ecosystem, with the loss of biomass, loss of biodiversity, casing changes in the nutrient cycle, quantity and quality of water and eventually destroying the habitat man is depending on for food, habitat and other research and educational values.
   
   (Pupils with this conclusion will be able to get 8 marks, if not only 7 marks will be awarded, when no evaluation is seen)