In most organisms, fertilization occurs between two haploid cells, the larger being called “female” or “egg” and the smaller being called “male” or “sperm." In most animals, meiosis is used to produce haploid eggs and… Meiosis generates variation in the daughter nuclei during crossover in prophase I as well as during the random alignment of tetrads at metaphase I.

Sexual reproduction requires that organisms produce cells that can fuse during fertilization to produce offspring. The cells that are produced by meiosis are genetically unique

meiosis — a nuclear division process that results in four haploid cells. meiosis I — first round of meiotic cell division; referred to as reduction division because the ploidy level is reduced from diploid to haploid. crossover — exchange of genetic material between nonsister chromatids resulting in chromosomes that incorporate genes from both parents of the organism. tetrad — two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I.