Alternation of generations

Definition

Alternation of generations is a life cycle in which organisms alternate between two distinct multicellular stages, haploid (gametophyte) and diploid (sporophyte). This cycle is common in plants, algae, and some fungi.

5 Must Know Facts For Your Next Test

1. 1. In the alternation of generations, the gametophyte produces gametes through mitosis.
2. 2. The sporophyte phase begins with the fusion of gametes to form a zygote.
3. 3. Sporophytes produce spores via meiosis, which then develop into new gametophytes.
4. 4. This life cycle ensures genetic diversity through both sexual and asexual reproduction stages.
5. 5. Mosses and ferns are classic examples of plants exhibiting alternation of generations.

Review Questions

• 1. What are the two main stages in the alternation of generations life cycle?
• 2. How do sporophytes produce spores?
• 3. Why is alternation of generations important for genetic diversity?

Related terms

Haploid: A cell or organism having a single set of chromosomes, typically found in gametes

Diploid: A cell or organism having two sets of chromosomes, one from each parent

Gametophyte: The haploid multicellular stage that produces gametes in the alternation of generations