Geography Paper 3 WASSCE (PC), 2017

Question 8

 

  1. Define ecosystem.
  2. Explain three ways in which the biotic and abiotic components of the ecosystem depend on each other.
  3. Highlight three benefits of the carbon cycle.

Observation

This question was fairly popular among the candidates and the performance of the candidates who attempted the question was above average.

Quite a good percentage of the candidates who answered the question were able to define the ecosystem as the relationship and interaction among the living and non-living things within an environment.

The ways in which the biotic and abiotic components of the ecosystem depend on each other include:
-           Autotrophs utilize sunlight, water and carbon dioxide during photosynthesis to produce their food
-           Carbon dioxide, water, sunlight and nitrogen provide nutrients and energy for the growth of plants
-           The primary consumers feed on the food produced by autotrophs from organic components
-           The various activities of man are carried out on the soil
-           The oxygen and carbon dioxide components of air are made constant through photosynthesis and respiration by living organisms
-           The decomposers break down the remains of other biotic components to form soils
-           Raw materials in the form of water, gases, and inorganic materials vital to the survival of the biotic components come from the physical environment
-           Plants depend on soil for support
-           Plants depend on soil for humus
-           Fish depends on water for survival
-           Plants depend on soil for supply of water and minerals
-           Soil depend on plants and animals for humus
-           Soils depend on plants and animals for weathering of parent rocks
-           Soil depends on plants for cover and shelter
-           Some animals depend on soil for their food e.g. earth worm

The benefits of the carbon cycle are:

-           Plants depend on carbon dioxide for photosynthesis
-           Plants absorb carbon dioxide and releases oxygen
-           Animals take in oxygen and releases carbon dioxide into the atmosphere
-           Animals depend on plants directly or indirectly for their food produced during photosynthesis
-           Carbon dioxide influences atmospheric temperature
-           Carbon cycle provides Carbon dioxide which is an important gas in the atmosphere.