Mutualism describes the ecological interaction between two or more species where each species has a net benefit.[1] Mutualism is a common type of ecological interaction. Prominent examples include most vascular plants engaged in mutualistic interactions with mycorrhizae, flowering plants being pollinated by animals, vascular plants being dispersed by animals, and corals with zooxanthellae, among many others. Mutualism can be contrasted with interspecific competition, in which each species experiences reduced fitness, and exploitation, or parasitism, in which one species benefits at the "expense" of the other. Mutualism is often conflated with two other types of ecological phenomena: cooperation and symbiosis. Cooperation refers to increases in fitness through within-species (intraspecific) interactions. Symbiosis involves two species living in proximity and may be mutualistic, parasitic, or commensal, so symbiotic relationships are not always mutualistic.
Mutualism plays a key part in ecology. For example, mutualistic interactions are vital for terrestrial ecosystem function as more than 48% of land plants rely on mycorrhizal relationships with fungi to provide them with inorganic compounds and trace elements. As another example, the estimate of tropical forest trees with seed dispersal mutualisms with animals ranges from 70–90%. In addition, mutualism is thought to have driven the evolution of much of the biological diversity we see, such as flower forms (important for pollination mutualisms) and co-evolution between groups of species.However, mutualism has historically received less attention than other interactions such as predation and parasitism.
The multicellular sporophyte of bryophytes turns a single fertilization event into thousands new haploid individual(s), whereas fertilization in Chara and Coleochaete leads to four new haploid individual(s).
