ENVIRONMENT
RAPID EVOLUTION IN ACTION
We think of evolution as a slow, gradual process, but that’s not always the case. Some species undergo a rapid transformation
WORDSALEX DALE
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Pollution from factories gave darker peppered moths an advantage
INSECT
MOTHS THAT GOT DARKER, THEN LIGHTER
The most famous example of ‘microevolution’ – evolution that occurs within 100 years and can be observed in a human lifetime – is a phenomenon we call ‘industrial melanism’. This most commonly occurs in butterflies and moths, and the most studied case is that of the peppered moth in Great Britain. Before the Industrial Revolution, the vast majority of peppered moths were white with a speckled pattern on their wings – only a small proportion of the species’ population boasted black bodies and wings. Natural selection favoured the white moths because their speckled colours allowed them to blend in with the lichen on tree bark, camouflaging them from predators.