Community Ecology The study of interactions between species of organisms living in the same area. Characterized by species richness and relative abundance of each species  Species Diversity

Interspecific Interactions Predation + / - Competition - / - Commensalism + / 0 Mutualism + / + Interspecific interactions are responsible for coevolution.

Examples of Coevolution Camouflage and Mimicry

Symbiosis Organisms living together

Competitive Exclusion Principle When two or more species in a community rely on similar limiting resources, they may be subject to interspecific competition. According to the competitive exclusion principle, two species with similar needs for the same limiting resources cannot coexist in the same place.

Competition in Paramecium

Ways to Lessen Competition Resource partitioning Character displacement

Keystone Species A species that makes an unusually strong impact on community structure. Example: Sea Star Pisaster’s role in biodiversity of Pacific intertidal zone.

Ecosystems All the living organisms along with all the abiotic facts. Important Concepts: Trophic Relationships Energy Flow Cycles of Chemical Elements Human Impact