Question

Select the correct statement for an occurrence of natural selection?

• A. Individuals must evolve.
• B. The environment must be constant.
• C. Variation among organisms must exist.
• D. Traits must be acquired.
• E. Many species must be present.

Answer 1

Answer: (C)

Variation among organisms must exist.

Genetic variation is an important force in evolution as it allows natural selection to increase or decrease the frequency of alleles already in the population. Genetic variation can be caused by the mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring). Genetic variation is advantageous to a population because it enables some individuals to adapt to the environment while maintaining the survival of the population.