The Peppered Moths of England

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The peppered moths of England are a prime example micro evolution. Here’s what happened:
Peppered moths are normally white with black spots all over its wings, hence its name: the peppered moths.  Additionally, there is a naturally occurring genetic mutation that causes some moths to have black wings instead of white wings with black spots. 
Here’s the catch. These peppered moths often land on lichen, which is like a white fungus that grows on trees.
The white peppered moths can camouflage well on the lichen because it is white. However, the black peppered moths cannot camouflage well on the lichen because black stands out on white. This means that they are more likely to be eaten by birds and other predators. As a result fewer black forms survive and their population is lower. So within the population of peppered moths, the majority are white with black spots, while a few are completely black. 
However, in the nineteen century, industrialization had taken over and the use of burning coal had caused great amounts of pollution which killed off the lichens and blackened the tree trunks. So now, the white form of the peppered moths were more obvious to predators while the black form of the peppered moths were less obvious to predators. Against the black pollution covered tree trunks in England, the black moths could blend in better. As generations passed, the moths adapted to the changed habitat and black moths began to outnumber white moths. Now, it was more common for a peppered moth to be born with black wings so it would live longer. This is microevolution, which are small changes within its kind. The moths’ tendency to reproduce as white with black spots changed to reproduce with fully black wings. By 1895, about 98% of the Peppered moths were black.
From that, we realized that pollution was a problem. In the mid-twentieth century controls were introduced to reduce air pollution. As the air quality improved, lichen growth increased and now white peppered moths could camouflage while the black moths were more noticeable, like before. As pollution decreased, the peppered moth population reversed back into its original state. Now, white moths dominate the population of peppered moths. We see that natural selection can work in both directions, favoring the moth that is best suited to the environmental conditions.

YouTube url:	https://www.youtube.com/watch?v=etsjB-6u-6w
Created:	11. 3. 2021 18:53:46

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The Peppered Moths of England