Theory question 105
Nutrient Cycling(a) Describe the water cycle using an annotated diagram(s) only
(b) What is the importance of water to living organisms?
Show the model answer
(a) Annotated diagram showing: water evaporates from seas, rivers and soil (sun's heat); transpiration from plants and respiration/sweating of animals add water vapour; vapour rises, cools and condenses into clouds; precipitation as rain, snow or hail; water runs off into rivers and seas, or soaks into the soil (infiltration) to form ground water, which is absorbed by roots; arrows linking each step in a cycle.
(b) Any: main part of protoplasm; solvent in which reactions take place; raw material for photosynthesis; medium of transport (blood, sap); keeps body temperature steady (sweating, transpiration); keeps plant cells turgid for support; habitat for aquatic organisms; needed for germination; medium for fertilisation in some organisms; removes wastes (urine); lubrication (synovial fluid, mucus).
In (a) use labelled arrows only, as the question asks for a diagram.