BIO153H5 Study Guide - Midterm Guide: Selaginella, Archegonium, Antheridium
Document Summary
In animals, the diploid (2n) organism undergoes meiosis and produces haploid (n), unicellular gametes (sperm and egg), which then fuse to form a diploid (2n) zygote. All plants on the other hand exhibit alternation of generations: the diploid (2n) part of the lifecycle (the sporophyte) undergoes meiosis to produce haploid spores, which then germinate to form a haploid (n) multicellular gametophyte (fig. The gametophyte then undergoes mitosis and eventually produces haploid (n) gametes (sperm and egg), which then fuse to form a diploid (2n) zygote. The alternation between the haploid (n) gametophyte and diploid (2n) sporophyte generations is where the lifecycle gets its name. Nonvascular plants tend to be structurally very simple, small, low to the ground, and generally inhabit moist areas. There are three phyla of nonvascular plants, hepatophyta (liverworts), Rhizoids, are short threads of cells that provide anchorage, but do not absorb water or nutrients.
