Question

(a) Define 'natural selection'.
(b) "Only variations that confer an advantage to an individual organism will survive in a population". Do you agree with this statement? Give reason for your answer.

Answer 1

(a) Natural selection is the process of evolution of a species in which characteristics that help individual organisms to survive and reproduce are passed on to their offsprings and those characteristics which do not help are not passed.

(b) Yes, we agree with the statement. Some changes always appear when animals produce their progeny by sexual reproduction. One of the progeny may be taller than the other. The advantage of long legs to the progeny is that when no food is available on the ground, those with long legs can reach the leaves on tall trees, eat them and survive. On the other hand, the progeny that are short cannot reach the leaves on tall trees. They will not get any food and eventually die from starvation. Now, since long legs are a beneficial variation, the long-legged animals will live long enough to produce their offsprings. So, all the future generations will be long-legged.