Question

Explain how crossing over and independent assortment provides variation and improves the chances of a species survival.

Please no pictures, please type response.

Answer 1

Crossing over is essential for the normal segregation of chromosomes during meiosis. Crossing over also accounts for genetic variation, because due to the swapping of genetic material during crossing over, the chromatids held together by the centromere are no longer identical.

Independent assortment produces new combinations of alleles.

In meiosis I, crossing over during prophase and independent assortment during anaphase creates sets of chromosomes with new combinations of alleles. Genetic variation is also introduced by random fertilization of the gametes produced by meiosis.

This variation allows some individuals within a population to adapt to the changing environment. Some new alleles increase an organism's ability to survive and reproduce, which then ensures the survival of the allele in the population.

Together with random fertilization, more possibilities for genetic variation exist between any two people than the number of individuals alive today.