# A population of Arctic foxes has individuals with either thick fur or thin fur. Explain how natural selection could result in thick fur becoming more common in the population over many generations, if the environment becomes colder.

> WJEC GCSE Biology (Wales) — 2.4.2 Evolution and natural selection · Explain · 4 marks

> Arctic foxes live in extremely cold environments. Within a population, some individuals have thick fur and some have thin fur. This variation is caused by mutations in the genes that control fur thickness.

## Mark scheme (4 marks)

1. There is variation in fur thickness within the population / some foxes have thick fur and some have thin fur
2. In a colder environment, foxes with thick fur are better suited / have an advantage / are more likely to survive
3. Foxes with thick fur are more likely to survive and reproduce / pass on the allele for thick fur to their offspring
4. Over many generations, the allele for thick fur increases in frequency in the population / thick fur becomes more common

## Key terms

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

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-population-of-arctic-foxes-has-8fe23cd5) · Published by Druglandscape Ltd.