Question

Which of the following is not true for a species?

• A. Members of a species can interbreed
• B. When gene pool is not fit, the species will go extinct
• C. Each species is reproductively isolated from every other species
• D. Individuals lost will threaten the survival of the species

Answer 1

The correct option is D Individuals lost will threaten the survival of the species

Species is defined as a group of individuals that can interbreed to produce a fertile offspring. And each species is reproductively isolated from every other species - they usually have mechanisms- physical, behavioural and physiological barriers that prevent interbreeding between members of two different species.
Individual genes denote the ‘fitness’ of an organism, while gene pool denotes the fitness of a species. Natural selection always operates at the population level or at species level. It is the ‘fitness’ of the gene pool that is of consequence for the survival of the species, individual genes lost are insignificant. It is when the ‘gene pool’ is not ‘fit’, that the species will go extinct.