What is the primary role of meiosis in organisms?

The primary role of meiosis is to create genetic diversity. This process involves two rounds of division that result in the formation of gametes (sperm and eggs in animals) with half the number of chromosomes of the original cell. During meiosis, particularly in the stages of prophase I, homologous chromosomes undergo crossing over, where segments of DNA are exchanged between non-sister chromatids. This exchange introduces new combinations of genes, thus enhancing genetic variation among the offspring produced through sexual reproduction.

Additionally, during metaphase I and anaphase I, the independent assortment of chromosomes contributes further to diversity. The random distribution of maternal and paternal chromosomes into gametes means that each gamete contains a unique set of genetic information. This genetic diversity is crucial for the evolution of populations, as it provides a pool of variations on which natural selection can act. Thus, meiosis plays a fundamental role not just in reproduction but also in the adaptability and evolution of species.