Why did the dark colored moths outnmber the light colored moth during the Industrial Revolution?

Answer 1

Answer

Thr trees that the moths resided on had previusly been a light white/grey colour. However, there was so much pollution as a result of the Industrial Revolution that the soot darkened the trees to a dark grey/blackish colour. The white moths had a higher population prior ot the Revolution because they blended into the trees and predators would eat the dark moths. But, once the trees became stained a darker colour, the light coloured moths were no longer able to blend into the trees.

DANGER! The above is a synopsis of Kettlewell's conclusions after his experiments with peppered moths in Great Britain during the 1950's. Later analysis has shown that Kettlewell's experiments were seriously flawed. Kettlewell "proved" that birds ate peppered moths perched on tree trunks during daylight hours by introducing a large population of peppered moths in enclosures with trees and birds, then he showed that the birds ate more of the light colored moths off the dark colored trees. Unfortunately, in nature, peppered moths are nocturnal, they hide during daylight hours, flying and feeding only during darkness, they do not normally perch on tree trunks during daylight hours. Also, bird predation is a trivial factor in peppered moth evolution, the main predators of peppered moths are bats, which catch them in flight not resting on tree trunks. Lastly, after tougher pollution laws took effect in the 1960's, and tree trunks became lighter again, Kettlewell did field observations which supposedly showed a rebound of light colored moths and the decimation of dark colored moths. While Kettlewell's original field notes have never been found, his observations do not comport with later and more scientific field studies. Bottom line - color camouflage and tree trunk color may have a tiny effect on light vs. dark moth populations but major shifts in moth coloration are dependant on other factors and whether there was actually a major shift in moth coloration (outside of Kettlewell's imagination) is open to question