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Question
Populations of peppered moths (Biston betularia) of England changed from 1% dark and 99% grey individuals to 99% dark and 1% light individuals between 1848 and 1898. The selective agent causing the change was ______.
Options
humans
birds
lichens on tree bark
smoke
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Solution
Populations of peppered moths (Biston betularia) of England changed from 1% dark and 99% grey individuals to 99% dark and 1% light individuals between 1848 and 1898. The selective agent causing the change was birds.
Explanation:
In the industrial areas of England, tree bark turned dark due to pollution, making dark moths harder to spot. Birds acted as the selective agents by eating more visible moths (first dark ones, later light ones). Thus, predation by birds caused the change in moth population.
