Question

Industrial melanism as observed in pepper moths proves that
A. The dark melanic form of the moth has no selective advantage over lighter forms in the industrial areas.
B. The lighter-form moth has no selective advantage either in polluted industrial areas or non-polluted areas.
C. Melanism is a pollution generated feature
D. The lighter form moth has an advantage in the non-polluted area but the dark moth has the advantage in the polluted area.

Answer 1

Hint: The effects of industrial revolution were seen in the fluctuating population of the light and dark coloured moths. The dark moths could easily hide themselves in the smoke covered trees while the lighter ones were exposed. While in a non-polluted area the dark moths could easily be seen while the lighter ones could camouflage in the surrounding.

Complete answer:
To solve the question, we must first know about industrial melanism.
There was a species of peppered moth in England. Before the industrial revolution the light coloured moth used to camouflage on the barks of the trees but the dark coloured moths were easily visible in the light background of the trees and fell an easy prey to the predators. The population of the dark coloured moths decreased drastically. During the industrial revolution several factories were set up. Due to this the pollution increased and the trees were now covered with smoke that matched with the colour of the dark coloured moths which could now easily camouflage in the dark background. But now the light coloured moths were visible so they fell an easy prey to the predators. Hence their population now decreased. But now the factories installed incinerators which cleaned the air before releasing it into the atmosphere. So now again the levels of pollution decreased and the light coloured moths could again hide in the barks and so their population increased further.

Therefore, the correct answer to the question will be that the lighter form moth has an advantage in the non-polluted area but the dark moth has the advantage in the polluted area.

Note:
The above study showed how natural selection actually works in nature. The moths which were fit to survive in the surroundings were selected while the rest were omitted. At times we often refer to natural selection as “the survival of the fittest”.