APES Species Interactions

resource partitioning

one of the species will evolve by natural selection to exploit different resources; * enables similar species to coexist in a community; birds may be in diff. part of a tree

character displacement

species diverge in body structure so they no longer compete for resources ex: finches: isolated, beaks became diff. sizes bc of diff. food sources

keystone species

species that help determine the types and numbers of other species in the community; play an important role in sustaining ecosystems

indicator species

species that serve as early warnings of environmental problems because they're sensitive to changes in the environment - birds - butterflies

mutualism

(+/+) both organisms, benefit from the interaction

predation

(+/-) an interaction where one species, the predator, kills and eats the other, they prey

parasitism

(+/-) one organism, the parasite, derives its nourishment from another organism, its host, which is harmed in the process

commensalism

(+/0) one organism benefits from the relationship and other organism is unaffected

competition

(-/-) two or more species "fight" for limited resources such as nutrients, living space, or light

amensalism

(-/0) one suffers and the other is not affected

examples of keystone species

- sea otters - pollinators - mangrove trees - grizzly bears

competition exclusion principle

if two species have the same ecological niche they cannot coexist, otherwise one will go extinct