BIOA02H3 Lecture Notes - Lecture 6: Ecological Niche, Interspecific Competition, Lichen

• School: UTSC
• Department: Biological Sciences
• Course: BIOA02H3
• Professor: Ivana Stehlik

Document Summary

Properties of communities: community: interaction pops. of different species found in same. 22 time/place, interrelationships govern flow of energy & nutrient cycling w/ in community. Ecological niche: hutchinson (1957, describes all abiotic components required for organism to thrive in. Variations in bill due to coevolution w/ flowers they pollinate. Evolutionary conservatism of niche based on food resources i. e. hummingbirds. Biological interactions: competition: when individuals use same resources resulting in lower fitness for both, intraspecific competition competition b/w individuals of same species, interspecific competition competition b/w individuals of different species, 2 types: Intraspecific competition: density-dependent (more individuals w/ in pop. greater competition for resources, when pop. densities reach certain threshold, resources become scarce. & fecundity per individual can decrease: competitive exclusion principle: hypothesis that 2+ species can"t coexist and use single, scarce resources. Competition & coexistence: competitor species can coexist in nature through many methods, 2 ways 2 species can coexist, better competitor in low #s.