Explain what is meant by interdependence and describe how the removal of one species from a woodland community could affect the other organisms living there.

Edexcel GCSE Biology (1BI0) — 9.1 Ecosystems · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

A woodland ecosystem contains oak trees, caterpillars that feed on oak leaves, blue tits that feed on caterpillars, and sparrowhawks that feed on blue tits. A disease kills all the caterpillars in the woodland.

Model answer (4 marks)

Interdependence is the dependence of different organisms on each other for survival.

The removal of the caterpillars would reduce the food available to blue tits, so their numbers would fall.

With fewer blue tits, sparrowhawks would have less prey and their population would also decline.

Oak trees would suffer less damage from caterpillars, so leaf cover and growth could increase.

Examiner tips

  • Use the exact definition of interdependence. Show the food‑chain link: caterpillar → blue tit → sparrowhawk. Explain the cascade effect on each species. Mention the positive effect on oak trees.
  • common_mistakes
  • :
  • Mixing up the order of the food chain. Forgetting to mention the oak trees’ benefit. Using vague terms like "affected" instead of "decrease" or "increase.

Mark scheme (4 marks)

  1. Interdependence is the dependence of different organisms on each other for survival
  2. Blue tit population would decrease because their food source (caterpillars) has been removed
  3. Sparrowhawk population would decrease because blue tit numbers have fallen, reducing the sparrowhawks' food supply
  4. Oak trees could be less damaged / increase in leaf coverage because there are no caterpillars feeding on their leaves

Key terms in this question

interdependence · community

Related

More Ecosystems questions

▶ Try answering this question with AI marking (free) →