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| Life Cycle Type | Definition | Mitosis and Meiosis | Sporophyte | Gametophyte | Examples |
|---|---|---|---|---|---|
| (Haplontic) | Organism spends most of its life cycle in the haploid (n) stage. The only diploid (2n) stage is the zygote, which undergoes meiosis to produce haploid spores. | Mitosis occurs in the haploid phase. Meiosis is zygotic, occurring in the diploid zygote to produce haploid spores. | Sporophyte is absent or very short-lived, represented only by the zygote. | Gametophyte is dominant and undergoes mitosis to produce gametes. | Spirogyra: Green alga, Volvox, Ulothrix |
| (Diplontic) | Organism spends most of its life cycle in the diploid (2n) stage. Gametes are the only haploid cells, which fuse to form a diploid zygote that grows into the adult. | Mitosis occurs in the diploid phase. | Sporophyte is dominant and undergoes mitosis for growth and development. | Gametophyte is very short-lived, represented only by the gametes. | Fucus: Brown alga Sargassum: Brown alga |
| Diplontic (Gymnosperms and Angiosperms) | Organism spends most of its life cycle in the diploid (2n) stage. Gametophytes are highly reduced to a few cells. | Mitosis occurs in the diploid phase. | Sporophyte is dominant and undergoes mitosis for growth and development. | Gametophyte is reduced to a few cells (pollen grains and ovules). | Gymnosperms: Conifers Angiosperms: Flowering plants |
| Haplodiplontic (Haplodiplontic) | Life cycle alternates between a multicellular haploid (gametophyte) phase and a multicellular diploid (sporophyte) phase. | Mitosis occurs in both haploid and diploid phases. Meiosis is sporic, occurring in the diploid sporophyte to produce haploid spores. | Sporophyte is multicellular and undergoes meiosis to produce haploid spores, which develop into gametophytes. | Gametophyte is multicellular and undergoes mitosis to produce gametes. | Ectocapous, Polysiphonia: Red alga Bryophytes: Mosses and liverworts Pteridophytes: Ferns |