5 2
The diagram shows some of the energy transfers through a countryside ecosystem. The numbers show the energy at each stage in kJ/m2/year. A
B
C
green plants
plant-eating insects
insect-eating birds
birds of prey
42 500
4000
800
150
(a) Calculate the efficiency for each energy transfer A, B and C.
efficiency of A .................... % efficiency of B .................... % efficiency of C .................... % [2] (b) Which energy transfer is least efficient? ........................................ Suggest why this energy transfer is least efficient. ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [2] (c) There are only four stages to this chain. In terms of energy transfer, explain why there can not be any more stages. ................................................................................................................................................... .............................................................................................................................................. [1] [Total: 5]
Š OCR 2013
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