Biology Regents Practice Exam

The main purpose of meiosis in sexual reproduction is to generate gametes with half the chromosome number, which is essential for maintaining the species' chromosomal integrity across generations. In sexual reproduction, two gametes, typically from different parents, fuse during fertilization to form a diploid zygote. If meiosis did not reduce the chromosome number, the zygote would end up with twice the normal number of chromosomes, leading to genetic instability. During meiosis, a single diploid cell undergoes two rounds of division, resulting in four haploid gametes. This halving of the chromosome number ensures that when two gametes combine, the resulting offspring has the correct diploid number of chromosomes. This process fosters genetic diversity as it involves recombination and random assortment of chromosomes, contributing to variation in traits among offspring, which is crucial for evolution and adaptation.