Here's why:
* Industrial Melanism: The change in moth coloration is specifically known as industrial melanism. During the Industrial Revolution, pollution darkened the trees where the moths lived.
* Survival Advantage: The darker moths, previously rare, were better camouflaged against the sooty trees, making them less likely to be eaten by birds. This gave them a survival advantage.
* Increased Reproduction: The darker moths, being better protected, lived longer and reproduced more, passing on their genes for darker coloration.
* Shifting Population: Over generations, the proportion of dark moths increased dramatically, while the light-colored moths declined.
In essence, natural selection favored the darker moths because they were better adapted to the changed environment.
