Community Ecology (Species Interactions)

symbiosis

long term relationship bt two species

mutualism

both species benefit

example of mutualism

clownfish and sea anenome

commemsalism

one benefits, the other is unaffected

example of commensalism

birds on cattle back

parasitism

one benefits while the other is harmed

competition

organisms compete to use same limited resource

intraspecific competition

between individuals of the same species

interspecific comeptition

between individuals of different species

exploitation competition

organisms compete indirectly through consuming limited resource

interference competition

individuals interact directly by physical force

competitive exclusion principle

two different species cannot occupy the same exact ecological niche at the same time

fundamental niche

full range of conditions where a species could live

realized niche

actual niche a species occupies

resource partitioning

differentiation of niches; enables similar species to coexist

Robert MacArthur

bird species occupied different heights/regions of a tree

ecological niche

specific role/ position a species has in its environment

character displacement

tendency for two species to diverge in morphology and resource use due to competition (Galapagos finches)

anti-predation strategies

chemical defense, aposematic coloration, cryptic coloration, mimicry, displays of intimidation

Mullerian mimicry

species converge to reinforce warning; stipes on bees and wasps

Batesian mimicry

harmless species mimics harmful one

donor controlled system

prey supply determined by factors other than predation

predator controlled system

action of predator feeding reduces supply of prey

bottom up model

food limitation controls population density

top down model

natural enemies control population densities