What is meiosis primarily responsible for?

Meiosis is a specialized type of cell division that is crucial for sexual reproduction. It results in the formation of gametes, which are the reproductive cells (sperm and eggs in animals). The primary purpose of meiosis is to reduce the chromosome number by half, creating haploid cells from diploid parent cells. This halving is essential because it ensures that when gametes fuse during fertilization, the resulting zygote has the correct diploid number of chromosomes.

Additionally, meiosis introduces genetic diversity through processes such as crossing over and independent assortment. Crossing over occurs during prophase I, where sections of homologous chromosomes exchange genetic material, leading to new combinations of genes. Independent assortment further promotes variability by ensuring that the distribution of maternal and paternal chromosomes to gametes is random.

This generation of genetically diverse haploid gametes is vital for evolution and a population's ability to adapt to changing environments. It facilitates variation among offspring, which is a key factor in natural selection and the overall resilience of a species.