# Biodiversity is important for the stability of ecosystems. Explain why a reduction in biodiversity can have serious consequences for an ecosystem, including the potential effects on food webs and human welfare.

> Pearson Edexcel A-Level Biology A (9BI0) — 2.5 Biodiversity · Explain · 5 marks

> Tropical rainforests contain millions of species of plants, animals, fungi and microorganisms. Human activities such as deforestation and pollution are causing species to become extinct at an increasing rate, reducing biodiversity in these ecosystems.

## Mark scheme (5 marks)

1. Biodiversity refers to the variety/number of different species in an ecosystem
2. Loss of a species can disrupt food webs, e.g. removal of a prey species reduces the food available for predators
3. Loss of one species can lead to the decline or extinction of other species (knock-on / cascading effects)
4. Reduced biodiversity threatens human welfare, e.g. loss of plant species reduces the potential for developing new medicines / food sources
5. Reduced biodiversity decreases ecosystem stability, making the ecosystem less able to recover from change / disturbance

## Key terms

- [biodiversity](https://www.gradenine.co.uk/glossary/biodiversity)
- [food web](https://www.gradenine.co.uk/glossary/food-web)
- [ecosystem](https://www.gradenine.co.uk/glossary/ecosystem)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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/biodiversity-is-important-for-the-stability-498ab80a) · Published by Druglandscape Ltd.