Industrial Smoke Changed Moth Coloration

During the Industrial Revolution, soot turned light-colored moths dark to help them hide from predators. When air quality laws finally cleared the pollution, the population naturally shifted back to being light-colored again.

This dramatic shift serves as one of the most famous real-time demonstrations of natural selection ever recorded. Before the coal era, dark moths were rare because they stood out against lichen-covered trees. As factories blackened the landscape, the dark moths suddenly held the survival advantage. Scientists marveled at how quickly the population adapted, proving Darwin's theory could be observed within a human lifetime.