# Explain how variation within a population of organisms can lead to some individuals surviving long enough to reproduce whilst others do not.

> Eduqas GCSE Biology — 2.4.2 Evolution and natural selection · Explain · 4 marks

> In a population of peppered moths, individuals show variation in wing colour, ranging from pale to very dark. In areas where tree bark is darkened by pollution, darker moths are more common.

## Mark scheme (4 marks)

1. Variation exists within the population / individuals in the population have different phenotypes / different wing colours
2. Some individuals have a characteristic / phenotype that is better suited to the environment / gives an advantage
3. Better-adapted individuals are more likely to survive and reproduce / less well-adapted individuals are more likely to be eaten / die before reproducing
4. The advantageous allele is passed on to offspring / the frequency of the advantageous allele increases in the population over many generations

## Key terms

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

## 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-how-variation-within-a-population-21d427e3) · Published by Druglandscape Ltd.