Mutualism
Symbiosis
-2 organisms live together in close association (physical contact) -May involve parasatism, mutualism, or commensalism
Dispersive Mutualism
-Animals transport pollen or seeds
Example of Dispersive mutualism (Seed dispersal)
-Blue jays eat acorns in the fall (disperse seeds over long distances and bury them in open areas. Some are left to germinate) -Monkeys eat fruit and defecate seeds. Dung beetles roll up dung and bury eat protecting seeds from seed eaters
Commensalism examples
-Elephants kill trees opening up habitat for grassland species -Cattle egrets eat insects stirred up by cattle -Arctic foxes eat food scraps left behind by polar bears
Trophic Mutualism (Grazing associations)
-Grazing by bison and pronghorns lower grass height providing better habitat for prairie dogs -bison forage on prairie dog town edges where young grasses have high nutrition value -Pronghorn forage in prairie dog town centers where forbs dominate over grasses
Example of Dispersive mutualism (hummingbirds)
-Hummingbirds are attracted to red and bright colors -Bill shapes of hummingbirds mimic flower shapes
Defensive Mutualism
-1 partner protects the other from predation, herbivory, or parasitism
Trophic Mutualsim
-1 partner obtains energy and nutrients from the other
Example of Trophic Mutualism
-Microbial fermentation -Rumenants (mammals with 4 stomachs) have bacteria in rumen which breaks down cellulose and synthesizes proteins and vitamins -Allows them to survive on low nutrition diet
Example of Dispersive mutualism (Bat pollinators)
-Nectivorous bats have long grooved tongues and broad wings for hovering -Bat pollinating flowers are drab and strongly scented (bats have strong sense of smell)
Obligate Mutualism
-Partners are fully dependent on each other for survival
Facultative mutualism
-Partners could survive without each other, but still benefit from association
Evolution of mutualistic relationships
-Probably started out as a predator prey relationship, parasitic host relationship -Both species exploit eachother in way that benefits both
Mutualism
-Relationship between 2 species in which both benefit -Can be either symbiotic or nonsymbiotic
Example of Defensive Mutualism
-Soay sheep on Scottish islands -As grazing pressures increase on red fescue grasses, rate of infection of fungi increases -Sheep crash every 3-5 years due to the poisioning of endophytic fungi