∞ generated and posted on 2016.12.30 ∞

Means of reestablishment of the diploid state in sexual organisms.

Fertilization above all is the conversion of two haploid cells into one diploid cell, particularly as observed at the very beginning of the life cycle of sexual organisms, that is, Fertilization restores the diploid state, and most familiarly (to us) involves the fusion of egg and sperm.

Fertilization, also known as syngamy, is the fusion of two gametes – most familiarly sperm and egg – to form a zygote. Thus two haploid gamete cells together form the diploid zygote.

Figure legend: Fertilization in its most familiar form, the fusion of sperm with egg.

This process of fertilization is in a sense one "half" the sexual cycle seen in eukaryotes as viewed from the perspective of genetics. That is, meiosis converts a diploid cell into haploid cells while fertilization converts haploid gametes into the diploid zygote. The zygote by various means then goes on to return the life cycle to meiotic generation of haploid cells which then go on by various means to generate the haploid gametes (see, for example, alternation of generations).