# Explain how the use of pesticides by farmers can have harmful effects on organisms that are not pests.

> WJEC A-Level Biology (Wales) — 3.6 Human impact on the environment · Explain · 5 marks

> Farmers use pesticides to kill insects and other organisms that damage their crops. However, scientists have found that pesticides can also harm other organisms living in and around farmland.

## Mark scheme (5 marks)

1. Pesticides are sprayed onto crops and can be absorbed by or remain on plants/soil/water
2. Non-target organisms (e.g. bees / birds / hedgehogs) eat or come into contact with the pesticide
3. Pesticide accumulates / builds up in the body of organisms (bioaccumulation)
4. Organisms higher up the food chain receive higher concentrations of pesticide (biomagnification)
5. This can kill or reduce the reproductive success of non-target organisms, reducing biodiversity / population numbers

## Key terms

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

## Related

- [Revision notes for WJEC A-Level 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-how-the-use-of-pesticides-3a541b64) · Published by Druglandscape Ltd.