Community Ecology Essential Standard Bio.2.1 Analyze the interdependence of living organisms within their environments.

Symbiosis Symbiosis – close interactions among species Predation, parasitism, competition, mutualism, and commensalism

Predation Predation - predator kills and consumes prey Predator’s survival relies on ability to capture food Prey’s survival relies on ability to avoid capture Mimicry – harmless species resembles a harmful one Camouflage – organisms blend into environment

Parasitism Parasitism – one individual benefits and the other is harmed but not killed Ex. Tick and dog; tapeworm and intestine

Competition Competition – different species compete for same resources (niche overlap) Competitive exclusion – one species is eliminated from community for same limited resource

Mutualism Mutualism – both species benefit from relationship Ex. Pollinator and flower; crocodile and crocodile bird

Commensalism Commensalism – relationship where one species benefits and the other is not affected

Properties of Communities Species Richness – number of species the community contains Species Diversity – number of species in relations to abundance of each species Community Stability – resistance to change Species richness improves community's stability Figure: When the sea star was removed from an area where the sea stars had preyed on the mussels, the mussels crowded out many other competing species in the area. Predation by the sea star on the mussel promoted diversity by controlling the superior competitor – the mussel. (Species Stability)

Ecological Succession Ecological Succession – gradual, sequential regrowth of species in an area Primary succession – development of community where there was no previous life Secondary succession – replacement of species that follows a natural disaster or human activity