Ecological Relationships and Species Interactions Developed by Steven Taylor Wichmanowski based on Pearson Environmental Science by Jay Withgott

Competition and Niches: Get in Where you Fit in Remember that a Niche includes an organism’s habitat, resource use, and functional role in an ecological community.

Interspecfic comptetion is competition among different species When two or more organisms are seeking the same resources (living space, food, sunlight, mates, water, etc.) they are in competition for these resources. Intraspecific competition is competition among members of the same species  Interspecfic comptetion is competition among different species

When two or more species are in competition for the same niche, two outcomes are possible:   Competitive exclusion: one species is so successful that the other species are pushed out of the niche completely (this can result in extinction of the less successful species, or simply disappearing from a specific community)  Resource partitioning: two or more species divide the resources of a niche (this can lead to specialized evolutionary adaptations)

Resource Partioning

Fundamental niche: the full potential niche of a species Because of competition, niches can be further divided into a species’ fundamental niche and their realized niche.  Fundamental niche: the full potential niche of a species  Realized niche: the actual niche of a species restricted by competition

Feeding Relationships Predation: a feeding relationship where one animal hunts, kills and consumes another animal. The hunter/eater is called the PREDATOR  The hunted/eaten animal is called the PREY

Generally speaking, predators have forward facing eyes and prey have side facing eyes. Why?

Apex Predator: The dominant predator at the top of a food chain

Symbiotic Relationships A symbiotic relationship is a long-term, physically close relationship between separate species where at least one organism benefits.

Mutualism: (+/+) a symbiotic relationship where both species benefit

Commensalism: (+/0) a symbiotic relationship where one species benefits and the other is not affected either positively or negatively

Parasitism: (+/-) a symbiotic relationship where one species benefits and the other is harmed

Coevolution Coevolution: occurs when species in an ecological relationship evolve in response to changes in each other. Coevolution can result from feeding relationships and/or symbiotic relationships