Haplontic

Definition

Haplontic refers to a life cycle in which the dominant stage is haploid, with only a brief diploid phase occurring during zygote formation. This type of life cycle is common in certain algae and fungi.

5 Must Know Facts For Your Next Test

1. In a haplontic life cycle, the organism spends most of its life in the haploid state.
2. The only diploid stage in this life cycle is the zygote, which quickly undergoes meiosis to return to the haploid state.
3. Haplontic organisms produce gametes through mitosis because their primary form is already haploid.
4. Haplontic life cycles are found in some green algae and fungi, including many species of Chlamydomonas and some Zygomycetes.
5. Unlike diplontic or alternation of generations life cycles, there is no multicellular diploid phase in haplontic organisms.

Review Questions

• What is the dominant stage in a haplontic life cycle?
• Which types of organisms commonly exhibit a haplontic life cycle?
• How does the transition from diploid to haploid occur in a haplontic organism?

Related terms

Diplontic: A life cycle where the dominant stage is diploid, with gametes being the only haploid cells.

Alternation of Generations: A type of plant lifecycle that alternates between a multicellular haploid gametophyte and a multicellular diploid sporophyte.

Zygote: The initial cell formed when two gamete cells are joined by means of sexual reproduction, typically diploid.