alternation of generations
Noun 1. the alternation of two or more different forms in the life cycle of a plant or animal (synonym) heterogenesis, xenogenesis (hypernym) organic phenomenon (hyponym) metagenesis, digenesis | ||||
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Alternation of generations Definition from Science & Technology Dictionaries & Glossaries
| Common Terms in Evolutionary Biology and Genetics |
Alternation of generations
An alternation of sexual (haploid) and asexual (diploid) form of generations in a life cycle (example: aphids). The relative dominance of each phase is variable in each organism (mosses have a dominant haploid phase whereas angiosperms have a dominant diploid phase). Besides aphids, Daphnia (water flea), rotifers, Hydra have alternation of generations in response to environmental conditions.
An alternation of sexual (haploid) and asexual (diploid) form of generations in a life cycle (example: aphids). The relative dominance of each phase is variable in each organism (mosses have a dominant haploid phase whereas angiosperms have a dominant diploid phase). Besides aphids, Daphnia (water flea), rotifers, Hydra have alternation of generations in response to environmental conditions.
Alternation of generations Definition from Encyclopedia Dictionaries & Glossaries
| Wikipedia English - The Free Encyclopedia |
Alternation of generations
Alternation of generations is a reproductive cycle of certain plants, fungi, and protists. The term is a bit confusing for people familiar only with the life cycle of a typical animal. A more understandable name would be "alternation of phases of a single generation" because we usually consider a generation of a species to encompass one complete life cycle. The life cycle of organisms with "alternation of generations" is characterized by each phase consisting of one of two separate, free-living organisms: a gametophyte (thallus (tissue) or plant), which is genetically haploid, and a sporophyte (thallus or plant), which is genetically diploid.
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