Editing Alternation of generations (section)

==Similar processes in other organisms==

=== Rhizaria ===

[[File:Foraminifera life cycle.png|thumb|upright=2|Life cycle of [[Foraminifera]] showing alternation of generations]]

Some organisms currently classified in the clade [[Rhizaria]] and thus not plants in the sense used here, exhibit alternation of generations. Most [[Foraminifera]] undergo a heteromorphic alternation of generations between haploid '''''gamont''''' and diploid '''''agamont''''' forms. The diploid form is typically much larger than the haploid form; these forms are known as the ''microsphere'' and ''megalosphere'', respectively.

=== Fungi ===
Fungal [[mycelia]] are typically haploid. When mycelia of different mating types meet, they produce two [[multinucleate]] ball-shaped cells, which join via a "mating bridge". Nuclei move from one mycelium into the other, forming a '''''[[heterokaryon]]''''' (meaning "different nuclei"). This process is called '''''[[plasmogamy]]'''''. Actual fusion to form [[diploid]] nuclei is called '''''[[karyogamy]]''''', and may not occur until [[sporangia]] are formed. Karogamy produces a diploid zygote, which is a short-lived sporophyte that soon undergoes meiosis to form haploid spores. When the spores germinate, they develop into new mycelia.

=== Slime moulds ===
The life cycle of [[slime mould]]s is very similar to that of fungi. Haploid spores germinate to form swarm cells or '''''myxamoebae'''''. These fuse in a process referred to as ''plasmogamy'' and ''karyogamy'' to form a diploid zygote. The zygote develops into a plasmodium, and the mature plasmodium produces, depending on the species, one to many fruiting bodies containing haploid spores.

=== Animals ===
Alternation between a multicellular diploid and a multicellular haploid generation is never encountered in animals.<ref name="Barnes-2001">{{Harvnb|Barnes|Calow|Olive|Golding|2001|p=321}}</ref> In some animals, there is an alternation between [[parthenogenesis|parthenogenic]] and [[sexual reproduction|sexually reproductive]] phases ([[heterogamy]]), for instance in [[salp]]s and [[Doliolida|doliolids]] (class [[Thaliacea]]). Both phases are diploid. This has sometimes been called "alternation of generations",<ref name="Scott-1996">{{Harvnb|Scott|1996|p=35}}</ref> but is quite different. In some other animals, such as [[hymenoptera]]ns, males are haploid and females diploid, but this is always the case rather than there being an alternation between distinct generations.