Answer/Explanation:
Pollution during the industrial revolution caused trees to become covered with soot, making them darker. This dark appearance meant that the peppered moth, which usually had a light colour, was clearly visible against the tree. This meant it was easier for predators to identify. As a result, their numbers decreased because they were an easier target.
However, there was also a rarer form of the moth, which was dark in colour. These were initially very rare. However, because of the change in the tree colour owing to the industrial revolution, these moths were better suited to the environment, as they were more camouflaged against the dark tree. This meant it was easier for them to avoid predators, and so they were more likely to survive to reproductive age and pass on the genes that produce the dark colour. This meant that the dark moths increased in number.
