What is the term alternation of generations?
Q: What is the term alternation of generations?
A: Alternation of generations is a term used to describe an alternation of forms in the life cycle of plants (and some protists). One form is diploid, with 2n chromosomes (the sporophyte), and the other form is haploid with only one set of chromosomes (the gametophyte). Both forms are multicellular.
Q: How does sexual reproduction work?
A: In sexual reproduction, organisms have a haploid phase with one set of chromosomes and a diploid phase with two sets of chromosomes. In animals the body (soma) is usually diploid, while the haploid stage is only the gametes.
Q: What does it mean when eukaryotes have an alternation of generations?
A: When eukaryotes have an alternation of generations, it means that both the diploid and the haploid phases are multi-cellular organisms. The classic example is mosses, where the green plant is a haploid gametophyte, and the reproductive phase is a diploid sporophyte.
Q: Does this term refer to sexual or asexual reproduction?
A: The term "alternation of generations" refers only to sexual reproduction; organisms may also have asexual reproduction as well.
Q: Is this term related to life cycle stages in animals?
A: No; this term should not be confused with life cycle stages in animals which may look very different but where all cells have two sets of chromosomes.
Q: What type of organism typically has an alternation between two forms?
A: Plants (and some protists) typically have an alternation between two forms - one form being diploid with 2n chromosomes (the sporophyte), and another form being haploid with only one set of chromosomes (the gametophyte). Both forms are multicellular.
