LIFE SCIENCE

Detailed explanation-1: -Genetic variation by itself will not result in natural selection unless it exerts some impact on organism survival and reproduction. However, any time all of Darwin’s postulates hold simultaneously-as they do in most populations-natural selection will occur.

Detailed explanation-2: -Natural selection can only occur if there is variation among members of the same species. WHY? Variation in a population results from mutation and the recombination of alleles during meiosis and fertilization.

Detailed explanation-3: -Without genetic variation, a population cannot evolve in response to changing environmental variables and, as a result, may face an increased risk of extinction. For example, if a population is exposed to a new disease, selection will act on genes for resistance to the disease if they exist in the population.

Detailed explanation-4: -Genetic variations that alter gene activity or protein function can introduce different traits in an organism. If a trait is advantageous and helps the individual survive and reproduce, the genetic variation is more likely to be passed to the next generation (a process known as natural selection).