Theory question 308
The Ecosystem(a) Define environmental balance. (b) With the aid of a diagram, explain water cycle. (c) In what three ways is water cycle beneficial to man?
Show the model answer
(a) Environmental balance is the state in which living things and the physical environment are in harmony, with natural processes keeping the components of the ecosystem stable.
(b) Diagram showing sea, land, clouds and arrows. Water from seas, lakes and rivers evaporates and plants transpire; water vapour rises, cools and condenses into clouds; precipitation (rain, snow) falls on land and sea; water flows back as surface runoff in rivers or infiltrates as groundwater which feeds springs and rivers; it returns to the sea and the cycle repeats.
(c) Provides rainfall for crops; replenishes rivers and groundwater for drinking and domestic use; water for industries; rivers for hydroelectric power; regulates temperature; supports fishing and transport.
Label evaporation, condensation, precipitation and runoff.