# Explain why removing all the top predators from an ecosystem would affect the populations of other organisms in that ecosystem.

> WJEC GCSE Biology (Wales) — 1.6.1 Ecosystems · Explain · 4 marks

> In some parts of the world, large predators such as wolves have been hunted and removed from ecosystems. This has had significant effects on many other species living there.

## Mark scheme (4 marks)

1. Top predators are consumers that feed on other animals (prey species), controlling their population size
2. Without top predators, the prey population would increase / not be kept in check
3. An increase in prey population leads to greater competition for food / resources among prey organisms
4. This reduces the population of producers / plants, which affects other organisms that depend on them (or vice versa — named organisms further down the food chain are affected)

## Key terms

- [top predator](https://www.gradenine.co.uk/glossary/top-predator)
- [population](https://www.gradenine.co.uk/glossary/population)
- [ecosystem](https://www.gradenine.co.uk/glossary/ecosystem)

## Related

- [Revision notes for WJEC GCSE Biology (Wales)](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-removing-all-the-top-66e36ec7) · Published by Druglandscape Ltd.