# Explain how natural selection can lead to evolution in a population of organisms over many generations.

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

> A population of beetles lives on dark-coloured tree bark. Some beetles have dark colouring and others have pale colouring. Birds hunt the beetles by sight.

## Mark scheme (4 marks)

1. Variation exists within the population / beetles show variation in colour
2. Dark-coloured beetles are better suited / have an advantageous phenotype as they are camouflaged on dark bark and are less likely to be eaten by birds
3. Dark-coloured beetles are more likely to survive and reproduce, passing on the advantageous allele(s) to offspring
4. Over many generations the frequency of the advantageous allele increases in the population, leading to a gradual change in inherited characteristics / evolution

## Key terms

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

## 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-natural-selection-can-lead-98f63d6b) · Published by Druglandscape Ltd.