Alternation of generations is defined as the alternation of multicellular diploid and haploid forms in the organism's life cycle, regardless of whether these forms are free-living. In some species, such as the alga See more

Fundamental elements
The diagram above shows the fundamental elements of the alternation of generations in plants. The many variations found in different groups of plants are described by use of these concepts later in the article. Starting … See more

It has been proposed that the basis for the emergence of the diploid phase of the life cycle (sporophyte) as the dominant phase (e.g. as in vascular plants) is that diploidy allows masking of the expression of deleterious mutations through genetic complementation. … See more

• Barnes, R.S.K.; Calow, P.; Olive, P.J.W.; Golding, D.W. & Spicer, J.I. (2001), The Invertebrates: a synthesis, Oxford; Malden, MA: Blackwell, ISBN 978-0-632-04761-1 See more

The term "plants" is taken here to mean the Archaeplastida, i.e. the glaucophytes, red and green algae and land plants.
Alternation of generations occurs in almost all multicellular red and green algae, both freshwater forms (such as Cladophora) and seaweeds (such as See more

Rhizaria
Some organisms currently classified in the clade Rhizaria and thus not plants in the sense used here, exhibit alternation of generations. Most See more

• Evolutionary history of plants#life cycles – Origin and diversification of plants through geologic time: Evolutionary origin of the alternation of phases
• Ploidy – Number of sets of chromosomes in a cell
• Biological life cycle – Series of stages of an organism See more