Alternation of generations

Definition

A reproductive cycle in which an organism alternates between two distinct forms: a haploid gametophyte (which produces gametes) and a diploid sporophyte (which produces spores).

Etymology

From Latin 'alternatio', meaning 'change' or 'alternation'.

Example

The life cycle of a fern alternates between a dominant sporophyte generation and a small, independent gametophyte generation.

Related Terms

• Gametophyte
• Sporophyte
• Life Cycle

Usage Notes

This phenomenon is common in plants and some algae, but not in insects or arachnids.