Ectosymbiosis - Wikipedia
An additional ectosymbiotic example of commensalism is the relationship between small sessile organisms and echinoids in the. In ecology, a biological interaction is the effect that a pair of organisms living together in a The six possible types of symbiosis are mutualism, commensalism, Parasitism is a relationship between species, where one organism, the parasite. Symbiosis is any type of a close and long-term biological interaction between In , Albert Bernhard Frank used the term symbiosis to describe the mutualistic relationship in lichens. In , the German.
commensalism - Memidex dictionary/thesaurus
Although these two populations spend a period of the year in the same place, and though there was evidence of gene flow between them, the difference in prey—habitat specialization has been sufficient to maintain genetic and even coloration divergence. The skull shape, tooth wear, and isotopic signatures suggested these remains were derived from a population of specialist megafauna hunters and scavengers that became extinct while less specialized wolf ecotypes survived.
Aspergillus and Staphylococcus Numerous genera of bacteria and fungi live on and in the human body as part of its natural flora.
The fungal genus Aspergillus is capable of living under considerable environmental stress, and thus is capable of colonising the upper gastrointestinal tract where relatively few examples of the body's gut flora can survive due to highly acidic or alkaline conditions produced by gastric acid and digestive juices.
While Aspergillus normally produces no symptoms, in individuals who are immunocompromised or suffering from existing conditions such as tuberculosisa condition called aspergillosis can occur, in which populations of Aspergillus grow out of control. Staphylococcus aureusa common bacterial species, is known best for its numerous pathogenic strains that can cause numerous illnesses and conditions.
However, many strains of S. Other Staphylococcus species including S. Arguments[ edit ] Whether the relationship between humans and some types of gut flora is commensal or mutualistic is still unanswered.
Species–area relationship - Wikipedia
Parasitism is an extremely successful mode of life; as many as half of all animals have at least one parasitic phase in their life cycles, and it is also frequent in plants and fungi. Moreover, almost all free-living animal species are hosts to parasites, often of more than one species. Mimicry Mimicry is a form of symbiosis in which a species adopts distinct characteristics of another species to alter its relationship dynamic with the species being mimicked, to its own advantage. Batesian mimicry is an exploitative three-party interaction where one species, the mimic, has evolved to mimic another, the model, to deceive a third, the dupe.
In terms of signalling theorythe mimic and model have evolved to send a signal; the dupe has evolved to receive it from the model. This is to the advantage of the mimic but to the detriment of both the model, whose protective signals are effectively weakened, and of the dupe, which is deprived of an edible prey.
For example, a wasp is a strongly-defended model, which signals with its conspicuous black and yellow coloration that it is an unprofitable prey to predators such as birds which hunt by sight; many hoverflies are Batesian mimics of wasps, and any bird that avoids these hoverflies is a dupe. Amensalism is an asymmetric interaction where one species is harmed or killed by the other, and one is unaffected by the other.
Evolutionary History[ edit ] Ectosymbiosis has evolved independently many times to fill a wide variety of ecological nichesboth temperate and extreme.
Additionally, in the case of mutualism, the evolution improved the fitness of both species involved, propagating the success of ectosymbiosis. Ectosymbiosis has independently evolved through convergent evolution in all domains of life.
Ectosymbiosis allows niches to form that would otherwise be unable to exist without the support of their host. Inherently this added niche opens up a new branch off of the evolutionary tree The evolutionary success of ectosymbiosis is based on the benefits experienced by the parasite and the host. Due to the dependence of the parasite on the host and the associated benefits and cost to both the parasite and host, the two will continue to coevolve as explained by the Red Queen hypothesis.
This niche specialization between species also leads to stabilization of symbiotic relationships between sessile and motile organisms.