# Explain why the extinction of one species in an ecosystem can lead to the decline of other species in the same ecosystem.

> Eduqas GCSE Biology — 2.1.2 Biodiversity · Explain · 4 marks

## Mark scheme (4 marks)

1. Species in an ecosystem are interdependent / depend on each other for food or resources
2. If one species is lost, species that feed on it lose a food source / prey species
3. This causes the population of those dependent species to decrease / decline
4. The effect can spread through the food web, affecting further species (knock-on / cascade effect)

## Key terms

- [extinction](https://www.gradenine.co.uk/glossary/extinction)
- [ecosystem](https://www.gradenine.co.uk/glossary/ecosystem)

## Related

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

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-the-extinction-of-one-30ff4804) · Published by Druglandscape Ltd.