Explain the action of natural selection with reference to industrial melanism.
Answers
There were two varieties of the peppered moth found in England, one was grey/whitish in color whereas the other was black.
Lichens are the symbiotic relation between algae and fungi, they are white or grey in color and are highly sensitive to pollution. Before the Industrial Revolution in Manchester (England), the air was pollution-free and lichens covered the tree trunks. The white moths could easily camouflage themselves between the lichens whereas the black moths were visible and were hunted by birds of prey.
After the Industrial Revolution, there was pollution in the air and thus, the lichens disappeared from the area and soot covered the tree trunks. Now, the black moths were able to camouflage themselves because of the presence of soot and the white ones were easily visible and were eaten by birds.
Thus, white moths were naturally selected according to the environmental conditions before the Industrial Revolution and black moths were naturally selected according to the conditions after the Revolution.
This phenomenon is called Industrial Melanism.
Natural selection in reference with melanism of industries is described below :
Moths of 2 varieties, that is, white winged and black winged were present.
1st Case :
Before the revolution of industries, more moths of white winged were present. The trunk of trees were of light color due to presence of lichens because at that time there was less pollution.
So, on the light background white winged moths were not so visible and hence the black winged were easily detected and eaten by predators.
2nd Case :
After the industrialisation, the trunks became black in color. And so the white moths were eaten easily by the predators.
Hence, black moths became huge in number.
This shows that nature selects the organisms that are better suitable.