Question

Which of the following evidences does not favour the Lamarckian concept of inheritance of acquired characters?

• A. Lack of pigment in cave-dwelling animals
• B. Evolution of variants of the peppered moth
• C. Absence of limbs in snakes
• D. Presence of webbed toes in aquatic birds

Answer 1

The correct option is B Evolution of variants of the peppered moth

Lamarckism talks about the inheritance of acquired characteristics. Options A, C and D are examples which support Lamarckism. However, the case of the peppered moths is different. Among the peppered moth Biston betularia, two variants existed during the 1800s in England - a light coloured type and a dark coloured type, of which the light coloured population was much bigger. During the Industrial Revolution, the soot and pollutants spit out from factories got deposited on the trees, which made the light coloured moths easy prey for predatory birds, as they were now easily visible against the dark background of the soot-covered trees. Thus, the population of the light coloured moths declined, while that of the dark coloured moths expanded, as the latter were eaten up less often. It was hence, nature who favoured one type over the other, as the former could survive better and reproduce in the respective surroundings. This case is an example of evolution by natural selection, and not by inheritance of acquired characteristics.