In England, after industrialisation set in, which of the following organisms showed more dark-coloured forms than white forms in the same area?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Moths
A collection made in England in the 1850s, before industrialisation, had more white-winged moths on trees than dark-winged (melanised) ones. A collection from the same area in 1920, after industrialisation, had more dark-winged moths. Smoke and soot darkened the tree trunks, so predators picked out the white moths and the dark moths survived.
Option (1) Lichens — Incorrect. Lichens were the almost white-coloured growth that covered the trees before industrialisation. They do not grow in polluted areas, which is why they serve as pollution indicators; they did not change colour.
Option (2) Darwin's finches — Incorrect. Darwin’s finches of the Galapagos Islands are an example of adaptive radiation, with beaks changed for different foods. NCERT does not link them with industrialisation.
Option (3) Moths — Correct. The moths of England showed more dark-winged forms after industrialisation, because camouflaged moths survived on the darkened trunks.
Option (4) Australian marsupials — Incorrect. Australian marsupials are another example of adaptive radiation on an island continent, not of colour change after industrialisation.
NCERT Extract:
What are the Evidences for Evolution? – “Another interesting observation supporting evolution by natural selection comes from England. In a collection of moths made in 1850s, i.e., before industrialisation set in, it was observed that there were more white-winged moths on trees than dark-winged or melanised moths. However, in the collection carried out from the same area, but after industrialisation, i.e., in 1920, there were more dark-winged moths in the same area, i.e., the proportion was reversed.”