LIFE SCIENCE

Detailed explanation-1: -Genetic variation can be caused by 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).

Detailed explanation-2: -Mutation: The change in the genes of individuals living in a population leads to genetic variation. Genetic recombination: The fusion of gametes promotes the various combination of genes in a population leading to genetic variation.

Detailed explanation-3: -Natural selection acts upon two major sources of genetic variation: mutations and recombination of genes through sexual reproduction. Most mutations do not affect the reproductive fitness of individuals–some may be beneficial, some may be harmful, and many may be neutral. Mutation rates per gene are generally low.

Detailed explanation-4: -Mutations, the changes in the sequences of genes in DNA, are one source of genetic variation. Another source is gene flow, or the movement of genes between different groups of organisms. Finally, genetic variation can be a result of sexual reproduction, which leads to the creation of new combinations of genes.

Detailed explanation-5: -Crossing over (in prophase I) Random assortment of chromosomes (in metaphase I) Random fusion of gametes from different parents.