Metagenesis

Part of speech: noun

Definitions

1. A biological process involving alternating forms of an organism, specifically the reproduction in different reproductive modes, often seen in certain invertebrates and plants
2. A cycle of development characterized by a switch in forms or generations, typically between sexual and asexual reproduction in certain species
3. The phenomenon where organisms exhibit two distinct phases of their life cycle, alternately reproducing through sexual and asexual means in response to environmental conditions

Etymology: "Metagenesis" is built from two Greek elements: "meta", meaning "after," "beyond," or "changed," and "genesis", meaning "origin" or "generation." Together they describe a process in which one generation gives way to a differently formed one, which is exactly what the biology names: a life cycle that alternates between sexual and asexual phases. The classic illustration is the jellyfish-like hydrozoans, where a sexually produced medusa and an asexually budding polyp take turns producing the next generation. The term is a technical coinage from classical roots rather than an ancient one, so the Greeks themselves would not have recognised it as a biological concept. Its usefulness lies in naming a pattern that the older word "alternation of generations" describes in more ordinary language.