Explain the phenomenon of evolution by natural selection as supported by the variations observed in white winged and dark winged moth populations in England between 1850 – 1920.

• Before industrialization set in thick growth of almost white coloured lichens covered the trees

• In that back ground the white winged moth survived but the dark coloured moths were picked out by the predators.

• During post industrialization period the tree trunks became dark due to industrial smoke and soot.

• Under this condition the white winged moth did not survive.

• The moths that were able to camouflage themselves in the back ground survived.