Meiosis occurs to produce haploid gametes required for sexual reproduction. It promotes genetic diversity in 3 different ways: crossing over, independent assortment and random fertilisation.Crossing over occurs in prophase one of meiosis and is when homologous chromosomes, having paired together, swap segments of DNA via chiasmata and therefore exchange genetic material increasing the diversity of the gametes.Independent assortment occurs at metaphase one and two and is when the chromosomes line up on the imaginary metaphase plate completely randomly and therefore increases diversity as chromosomes can be paired randomly and sent to any one of the daughter cells.Random fertilisation also promotes genetic diversity as any one of the millions of sperm haploids produced can fertilise the specific egg that was released out of the many millions a female has.