Question

Which of the following phenomena supports Darwin's concept of natural selection in organic evolution?

• A. Development of transgenic animals
• B. Production of 'Dolly', the sheep, by cloning
• C. Prevalence of pesticide resistance in insects
• D. Both a and b

Answer 1

The correct option is C Prevalence of pesticide resistance in insects

According to natural selection theory, as a result of struggle for existence only those organisms could survive which have favourable variations to adapt themselves to the environmental conditions (survival of the fittest). Prevalence of pesticide resistance in insects, e.g., DDT resistant mosquitoes are a result of natural selection. It is because the mutant strain of DDT resistant mosquitoes were able to survive even after the exposure to DDT. Hence, they were able to outnumber the population. Due to selection, these varieties soon became well established and replaced the original DDT-sensitive mosquitoes.

On the other hand, development of transgenic animals and production of Dolly have been accomplished by human intervention. These do not justify survival of the fittest as per Darwin's theory of natural selection.