Peppered moths

In England, the peppered moth population suffered some drastic changes. As the trees were turning black, due to pollution coloring their bark. There were a few theories explaining why this was happening. One was that the pollution was also dyeing the moths' wings, as it was the trees' bark. The most prominent one, however, was that the moths were adapting to suit their environment better. The moths were originally colored to suit the peppered shade of the tree bark, as to provide a form of natural camouflage. As the trees became darker, the darker moths were harder for predators to see and thus survived longer. There had been very few dark moths seen earlier, as they were spotted and eaten quickly.

One of the main scientists promoting the theory was Kettelwell. Kettelwell went through a long series of experiments to test that the black color was actually a genetic mutation, and that it was rapidly spreading through the population due to natural selection. All of these test confirmed Kettelwell's theory, and as England's pollution is decreasing, and most scientists belief that as that happens the population of light moths will go up as well.