gameten

Gameten, in English commonly called gametes, are the reproductive cells that fuse during sexual reproduction to form a new organism. They are typically haploid, containing a single set of chromosomes, and arise by meiosis in specialized germ cells. In animals, the main types are sperm, the male gametes, and ova (eggs), the female gametes. In plants, fungi, and many algae, gametes are produced by the gametophyte generation; in flowering plants, the male gametophyte is the pollen grain that carries sperm to the female gametophyte inside the ovule.

Gametogenesis is the process of forming gametes. It includes spermatogenesis and oogenesis in animals, and analogous processes in plants and fungi. Gametes fuse in fertilization (syngamy) to form a diploid zygote, restoring the chromosome number and initiating development.

Modes of gamete size and mobility vary. Isogamy refers to similar-sized gametes; anisogamy to unequal sizes; oogamy to a large non-motile egg and a small motile sperm. Many species show anisogamy or oogamy, reflecting different reproductive strategies.

In life cycles with alternation of generations, the haploid gametophyte produces gametes that fuse to form a diploid zygote, which grows into the sporophyte; in other lineages, the diploid phase dominates and gamete formation occurs in adulthood.

Examples include humans (sperm and eggs) and flowering plants (pollen and ovules). Gametes enable genetic recombination and variation, contributing to evolution and adaptation.