# Explain how a population of peppered moths could change over time if the trees in their habitat became covered in dark soot due to industrial pollution.

> OCR GCSE Biology A: Gateway Science (J247) — B5.2 Natural selection and evolution · Explain · 4 marks

> Before industrial pollution, most peppered moths in England had light-coloured wings that camouflaged them against pale, lichen-covered tree bark. Over several generations following the growth of industrial factories, the proportion of dark-winged moths in the population increased significantly.

## Mark scheme (4 marks)

1. Random mutation produces variation in wing colour within the population (e.g. some moths have dark wings)
2. Dark-winged moths are better camouflaged on soot-covered trees and are less likely to be eaten by predators
3. Dark-winged moths are more likely to survive and reproduce, passing the advantageous allele to offspring
4. Over many generations the frequency of the dark-wing allele increases in the population (natural selection)

## Related

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