What is "asexual reproduction"

Reproduction \Re`pro*duc"tion\ (-d?k"sh?n), n. [Cf. F. reproduction.]

1. The act or process of reproducing; the state of being reproduced; specifically (Biol.), the process by which plants and animals give rise to offspring.

   Note: There are two distinct methods of reproduction; viz.: asexual reproduction (agamogenesis) and sexual reproduction (gamogenesis). In both cases the new individual is developed from detached portions of the parent organism. In asexual reproduction (gemmation, fission, etc.), the detached portions of the organism develop into new individuals without the intervention of other living matter. In sexual reproduction, the detached portion, which is always a single cell, called the female germ cell, is acted upon by another portion of living matter, the male germ cell, usually from another organism, and in the fusion of the two (impregnation) a new cell is formed, from the development of which arises a new individual.

2. That which is reproduced.

n. 1 (context biology English) Any form of reproduction that does not involve the fusion of gametes. 2 (context biology English) Any form of reproduction that involves neither meiosis nor fusion of gametes.

n. reproduction without the fusion of gametes [syn: agamogenesis]

Asexual reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes and almost never changes the number of chromosomes. Asexual reproduction is the primary form of reproduction for single-celled organism as the archaea, bacteria, and protists. Many plants and fungi reproduce asexually as well.

While all prokaryotes reproduce asexually (without the formation and fusion of gametes), mechanisms for lateral gene transfer such as conjugation, transformation and transduction are sometimes likened to sexual reproduction (or at least with sex, in the sense of genetic recombination). A complete lack of sexual reproduction is relatively rare among multicellular organisms, particularly animals. It is not entirely understood why the ability to reproduce sexually is so common among them. Current hypotheses suggest that asexual reproduction may have short term benefits when rapid population growth is important or in stable environments, while sexual reproduction offers a net advantage by allowing more rapid generation of genetic diversity, allowing adaptation to changing environments. Developmental constraints may underlie why few animals have relinquished sexual reproduction completely in their life-cycles. Another constraint on switching from sexual to asexual reproduction would be the concomitant loss of meiosis and the protective recombinational repair of DNA damage afforded as one function of meiosis. (Also see Meiosis section: Origin and function of meiosis)