Question

How do the observations made during moth collection in pre- and post- industrialized era in England support evolution by Natural Selection?

Answer 1

Industrial melanism is an example of the natural selection of a particular form of an organism in an environment which has changed due to the ill effects of pollution created by industrial activities. The peppered moth  Biston betularia is found in Manchester, England. It exists in two forms, one a light patchy white and the other a sooty black. Under normal conditions, the majority of the white moths survive because the trees they rest on have white bark. The black moths have negligible numbers. Due to the industrial revolution in Manchester, the number of industrial establishments increased manifold, and the soot released from their chimneys started coating the tree trunks nearby, turning them black. The black variety now started getting camouflaged better on these blackened trunks, and their numbers rose and stabilized. The number of the white variety dwindled due to predation as they started getting easily spotted on the black trunks and get easily picked up by predators. This represents a very clear example of the natural selection.