# Explain how natural selection can lead to a population of organisms becoming better adapted to their environment over many generations.

> AQA A-Level Biology (7402) — 3.4.4 Genetic Diversity and Adaptation · Explain · 5 marks

> A population of moths lives in a woodland area. The bark of the trees is pale in colour. A dark-coloured variant of the moth occasionally appears due to mutation.

## Mark scheme (5 marks)

1. There is variation within the population (e.g. some moths are pale, some are dark)
2. Predators are less likely to spot pale moths against pale bark (selective pressure / predation acting as selection pressure)
3. Pale moths are more likely to survive and reproduce
4. Pale moths pass on their alleles / genes for pale colouration to offspring
5. Over many generations the proportion of pale moths in the population increases, so the population becomes better adapted

## Key terms

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

## Related

- [Revision notes for AQA A-Level Biology (7402)](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-1b6090ec) · Published by Druglandscape Ltd.