[amurale]

Something like that. Evolution = natural variation + natural selection.

In any given population there is natural variation: fastest moth, hairiest moth, whitest moth, etc. After evolutionary pressure is applied, the other moths are preferentially devoured, and the hairiest moth becomes the dominant variation with the most offspring.

For a similar historic account, read about the black form of the peppered moth which rapidly took over the moth population, caused by evolutionary pressure + single mutation in the year 1819.

https://www.bbc.com/news/science-environment-36424768