Biological Niche An organism’s Niche describes the full biotic and abiotic conditions in which an organism lives – Biotic factors: Predators Prey competition Vegetation – Abiotic factors: Climate Soil (nutrients) Terrain

Community Interactions Interactions of a community: interactions that affect an ecosystem and drive evolution – Competition - negative effect on both species interspecific competition - 2 species compete for the same resource Interspecific interactions and adaptation – drives coevolution and adaptation of species living in close proximity to each other – exclusion principle states that no 2 species can occupy the same niche

Community Interactions Predation - benefits one and has a negative effect on the other – drives evolution - mimicry and other diverse adaptations – The number and phenotype of the prey determines the phenotype and number of the predators

Community Interactions Symbiosis… “Same Life” – Mutualism - benefits both equally – Commensalism - one is benefited while the other is unaffected very rare in nature

Community Interactions Parasitism - parasite benefits while the host is harmed – Parasite obtains most or all of its nutrition from the host – Can exert a substantial influence on a population – The parasite generally weakens but does not kill the host – Disease - similar to parasite

Ecological Succession Ecological succession refers to the slow changes in an ecosystem over time – Primary succession Begins with NO soil – New islands, bare rock following glacier movement, and volcanic debris are examples – Lichens (pioneer species) … fungus that breaks down rocks to form soil

Ecological Succession Secondary Succession – Process of restoring ecological balance once soil is present Following a fire is an example – Reestablishment of a forest can take up to 300yrs – The climax community is a representative of the stable ecosystem