Alternation of Generations in a Plant Life Cycle

By Rene Fester Kratz

Part of Botany For Dummies Cheat Sheet

During the life cycle of a plant, the plant alternates between two forms: the sporophyte generation and the gametophyte generation. So, a complete plant life cycle includes both generations.

Characteristics Sporophyte Generation Gametophyte Generation
Ploidy (# of sets of chromosomes) Diploid (2 sets of chromosomes) Haploid (1 set of chromosomes)
Types of cell division and what they’re used for Mitosis to grow
Meiosis to produce haploid spores, which begin the gametophyte
Mitosis to grow
Mitosis to produce haploid gametes, which join together to form the
sporophyte generation
How the generation begins Begins when haploid gametes (sperm and egg) fuse to form a
diploid zygote
Begins when the sporophyte produces a haploid spore
What it looks like in different kinds of plants Most visible form in ferns, gymnosperms, and angiosperms
Small structures on mosses and lycophytes that grow on the
Most visible form in mosses and lycophytes
Small but independent structure in ferns’ very small
structures in gymnosperms and angiosperms that are enclosed by the