# A woodland ecosystem contains oak trees, caterpillars, blue tits, and sparrowhawks. When humans began over-harvesting blue tits from this woodland, describe the effect this would have on the populations of caterpillars and sparrowhawks. Give reasons for your answers.

> Cambridge International IGCSE Biology (0610) — 19.2 Food chains and food webs · Describe · 4 marks

## Mark scheme (4 marks)

1. Caterpillar population increases
2. Reason: fewer blue tits means fewer caterpillars are eaten / predation of caterpillars decreases
3. Sparrowhawk population decreases
4. Reason: fewer blue tits means sparrowhawks have less food / sparrowhawks cannot get enough energy to survive and reproduce

## Key terms

- [over-harvesting](https://www.gradenine.co.uk/glossary/over-harvesting)

## Related

- [Revision notes for Cambridge International IGCSE Biology (0610)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-woodland-ecosystem-contains-oak-trees-21e1ab88) · Published by Druglandscape Ltd.