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7.4 Trophic levels in an ecosystem

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Question 4

Two species of freshwater snail feed on the same species of algae. Each snail eats 8.0 g dry mass of algae.

Snail speciesDry mass of algae eaten in gDry mass of faeces produced in g
A8.02.0
B8.01.2
a.

Calculate the percentage of the biomass eaten by snail species A that is lost in its faeces.

[2]
b.

Explain why the efficiency of biomass transfer from the algae to snail species B may be greater than the efficiency of transfer to snail species A.

[2]
Markscheme

7.4 Trophic levels in an ecosystem Questions

  1. GCSE
  2. /Biology
  3. /7.4 Trophic levels in an ecosystem

103 exam-style questions on AQA GCSE Biology 7.4 Trophic levels in an ecosystem, covering 7.4.1 Trophic levels, 7.4.2 Pyramids of biomass, and 7.4.3 Transfer of biomass. Each one has a worked solution and a mark scheme showing where the marks go.

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