Modes of Reproduction

Every mode of reproduction, however different it looks on the surface, shares a few basic cellular events underneath: synthesis of RNA and proteins, replication of DNA, cell division and growth, the formation of dedicated reproductive units, and, where two units are involved, their fertilization to build a new individual. Organisms show two broad reproductive strategies. Asexual reproduction involves only a single parent and does not use gametes at all — it typically proceeds by amitotic or mitotic division of ordinary body (somatic) cells, which is why it is also called somatogenic or blastogenic reproduction, and because no gametes fuse, the offspring it produces are genetic copies of the parent. Sexual reproduction, in contrast, needs two parents and two distinct kinds of gametes — the ovum (egg) from the female and the sperm from the male — whose fusion creates a genetically new individual. Some organisms are not locked into just one strategy …