Alternation of generations: Quick Facts

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Facts

Also Known As	diplohaplontic cycle • metagenesis • heterogenesis • diplohaplontic life cycle

Photos

fern: life cycle

Diagram showing the life cycle of moss, including spore release from capsules, germination into protonema, development into leafy gametophytes, fertilization of eggs by sperm, zygote formation, and growth of new sporophytes.

Life cycle of the common jellyfish Aurelia. Eggs released by females pass out through the mouth and become lodged in pits on the tentacles. Sperm released from male jellyfish fertilize the eggs, which remain on the tentacles during early development. A fertilized egg develops into a ciliated larva, or planula, which settles on and attaches to a substrate (such as a rock) and develops into a polyp with a mouth and tentacles. The polyp reproduces asexually by budding off saucer-shaped immature medusae, which develop into mature sexually reproducing forms.

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Topics

haploid phase diploid phase gametophyte sporophyte foot spore mother cell microgametophyte megagametophyte gametophore spore plant development seed fruit germination annual perennial biennial

Key People

Frederick Orpen Bower, detail of an oil painting by Sir William Orpen; in the University of Glasgow Art Collections

Frederick Orpen Bower

English botanist