The purpose of meiosis is to produce gametes, or sex cells. During meiosis, four daughter cells are produced, each of which are haploid (containing half as many chromosomes as the parent cell).

The purpose of meiosis is to shuffle genetic information and cut the cellular chromosome number in half, from 46 chromosomes to 23 chromosomes. In this way, when an egg and sperm cell combine during fertilization, the resulting embryo will inherit the appropriate amount of unique genetic information from each parent.

In prophase I of meiosis, the homologous chromosomes form the tetrads.

The crossover events are the first source of genetic variation produced by meiosis. A single crossover event between homologous non-sister chromatids leads to an exchange of DNA between chromosomes.

Without genetic variation, a population cannot evolve in response to changing environmental variables and, as a result, may face an increased risk of extinction. But if they do not exist — if the right genetic variation is not present — the population will not evolve and could be wiped out by the disease.

Natural selection acts upon two major sources of genetic variation: mutations and recombination of genes through sexual reproduction.

There are two forms of variation: continuous and discontinuous variation.

‘Genetic variation’ describes the naturally occurring differences in DNA sequences that are found among individuals of the same species. These genetic differences arise from random mutations and may be passed on to their offspring.

Examples of genetic variation include eye color, blood type, camouflage in animals, and leaf modification in plants.

Genetic variation is advantageous to a population because it enables some individuals to adapt to the environment while maintaining the survival of the population.