Question

State a reason for the increased population of dark coloured moths coinciding with the loss of lichens (on tree barks) during industrialization period in England.

Answer 1

Industrial melanism was the reason behind the increase in the population of dark-coloured moths along with the loss of lichens during industrialisation in England.

The tree trunks became darker (after pollutants being emitted by the industries) with deposits of soot and smoke which didn't allow lichens to survive on the tree barks. As a result, the white-winged moths were not able to hide between the lichens. Hence, the number of dark moths increased as they were not easily visible to their predators while the white-winged ones were easily picked up by the predators (due to a reduction in lichens). Thus, dark ones were selected by nature (natural selection) and light ones failed to survive.