Explain why decomposers are important in an ecosystem.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Decomposers break down dead organisms and organic material, releasing nutrients and minerals into the soil. These nutrients can then be absorbed by plants, allowing the cycling of nutrients to continue in the ecosystem.
Examiner tips
- Use the exact terms "decomposers", "break down", "release nutrients", "soil", "plants", "cycling".
- Show the causal chain: decomposition → nutrient release → plant uptake → nutrient recycling.
- Keep answer concise – 4 points, one sentence each.
- Avoid extra words or explanations not asked for.
Common mistakes
- Using vague terms like "animals" instead of "decomposers".
- Omitting the step that plants absorb the released nutrients.
- Not mentioning the recycling/cycling of nutrients.
Mark scheme (4 marks)
- Decomposers break down dead organisms / organic material
- Decomposers release nutrients / minerals into the soil
- Nutrients / minerals can then be absorbed / taken up by plants
- This allows nutrients to be recycled / cycling of nutrients to continue in the ecosystem
Key terms in this question
Related
- All WJEC GCSE Biology (Wales) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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