# A species of moth lives in woodland areas. The moths rest on tree bark during the day. The tree bark is covered in pale-coloured lichen. Most moths in the population have pale-speckled wing patterns, but a small number have dark wing patterns. Explain how natural selection could lead to a change in the proportion of dark-winged moths in this population if the woodland trees lose their lichen covering and the bark becomes dark in colour.

> Pearson Edexcel A-Level Biology A (9BI0) — 2.6 Adaptation and natural selection · Explain · 5 marks

> A species of moth lives in woodland areas. The moths rest on tree bark during the day. The tree bark is covered in pale-coloured lichen. Most moths in the population have pale-speckled wing patterns, but a small number have dark wing patterns.

## Mark scheme (5 marks)

1. There is variation in wing colour/pattern within the moth population
2. When bark becomes dark, dark-winged moths are better camouflaged / better adapted to the environment
3. Pale-speckled moths are more easily seen by predators and are more likely to be eaten / have a lower chance of survival
4. Dark-winged moths are more likely to survive and reproduce, passing on their alleles/genes for dark wing colour to offspring
5. Over many generations, the proportion of dark-winged moths in the population increases

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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/a-species-of-moth-lives-in-9c3b6417) · Published by Druglandscape Ltd.