The environment helps decide what thrives.
Field Notes
For centuries, most peppered moths were light colored, blending into tree bark covered in pale lichens. During the Industrial Revolution, pollution darkened many trees with soot. Suddenly, the same coloring that once provided camouflage became easier for predators to spot. Darker moths survived more often and became more common. When pollution later declined and lichens returned, the trend reversed. The story is often taught as an example of evolution, but it also illustrates a broader pattern: when environments change, different strengths become useful. What thrives is shaped not only by what it is, but by the conditions around it.