Populations

Section #2:How Species Interact

With Each Other

Niche

•the unique role of a species within an ecosystem

•the pattern of use of its habitat

•the job a species plays in an ecosystem

Ways in Which Species Interact

• competition• predation• parasitism• mutualism• commensalism• symbiosis• coevolution

Competition

• attempts to use the same limited resource

• within or between species (niche overlap)

• indirect – one feeds a night, other during the day

• niche restriction – use less than they are capable of using

Predation

•predator feeds on prey•prey have evolved

mechanisms to avoid or defend predators–camouflage–warning coloration–mimicry–protective covering

Parasitism

•organism lives on or in another and feeds on the host

•host rarely is killed by parasite because its better for the parasite to keep the host alive – host just weakens or is exposed to disease

Mutualism

•a close relationship between 2 species where each provides a benefit for the other

•often survival depends on this relationship

•ex. = bacteria in our intestines

Commensalism

•relationship where one species receives benefit while other species is neither helped nor harmed

•ex. = sharks & remoras

Symbiosis

•relationship in which two organisms live in close association

•in most, at least one species benefits

Coevolution

•over time, organisms with symbiotic relationships coevolve

•where the species develop adaptations that improve the benefits received

•ex. = flowering plants & insects

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