Question

Question 36 2 pts How does the sexual life cycle increase the genetic variation in a species? by allowing crossing over by conserving chromosomal gene order by increasing gene stability by allowing fertilization

Answer 1

In the sexual life cycle fertilization is the most eminent step. Fertilization is the fusion of male gamete (sperm) and female gamete (ova/egg). These gametes are haploid cells formed due to a special type of cell division found in the germ cells of the male and female known as meiosis. In the meiosis type of cell division the DNA content of the cell decreases to half. Also in the Metphase - 1 stage of the Meiosis-1 a process known as crossing over takes place. In the crossing over, the homologous chromosomes pair and exchange of genetic materials takes place between the non-sister chromatids. This results in a new combination of the chromosomes and having a varied combination of genetic material.

Fertilization is the combination of the male gamete with the female gamete. In this process there is no specificity that with which sperm the ova will get fertilized and also each and every sperm of the male contains different genetic combination due to the crossing over takes place during the formation of gamete or the meiosis cell division of the germ cells.

Hence if we think critically, both the crossing over and fertilization processes have significant effect on the genetic variation in a species. But when we look upon the processes that taking place during the life cycle of an organism we can conclude that crossing over is the first step which has contributary effect on the genetic variation in a species.

But generally both the crossing over and fertilization process have significant effect on the variation in a species, but as the question is about sexual life cycle and genetic variation,I have took the first and basic process I.e. crossing over as the answer, otherwise both crossing over and fertilization will be the right answers for this question.