Q.38 The evolutionary story of moths in England during industrialisation reveals, that ‘evolution is apparently reversible’. Clarify this statement.

During the last century in the industrial regions of England, a light coloured peppered moth Biston betularia was found on the bark of trees. The tree bark was covered by whitish

lichens, so light coloured moths escaped unnoticed from predatory birds.

After industrialisation, barks got covered by smoke, so the white moths were selectively
picked up by birds. However, the black coloured moths escaped unnoticed against a dark
background and became abundant.

However, in recent years, reduced industrial pollution has led to the growth of lichens again
and thus, the population of light coloured moths is again increasing,

This evolutionary story of moths in England, thus reveals, that ‘evolution is apparently