Here's why:
* Historically: Before the Industrial Revolution, the peppered moth was predominantly light-colored with black speckles, allowing it to blend in with lichen-covered tree trunks. This camouflage protected it from predators like birds.
* Industrial Pollution: As factories released soot and pollution, the tree trunks darkened. The light-colored moths became more visible, making them easier prey.
* Melanistic Form: A naturally occurring darker form of the peppered moth (called the "melanic" form) became increasingly common in polluted areas. This darker form provided better camouflage on the darkened tree trunks, giving them a survival advantage.
* Evolution in Action: This shift in moth coloration dramatically demonstrated how natural selection can drive rapid evolutionary changes in response to environmental pressures.
The peppered moth is a textbook example of industrial melanism and how pollution can affect the evolution of species.
