BIOL-2356EL Lecture Notes - Lecture 17: Plant Community, Commensalism, Herbivore
4 Mar 2020
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Document Summary
Community : a group of interacting organisms inhabiting a given area. Studies are often limited to a certain group of organisms. The difference between a community and a mere collection of species is the accommodation that the species make for each other. The community is not the presence of a particular set of organisms, it is the difference in the organisms because the other community members can be expected to be present : interactions! Vole gets killed negative predatory -prey: cat gets food positive. Butterfly gets food positive, plant gets pollinated positive. Types of interactions defined by effect on both organisms: Mutualism mycorrhiza associations between plant roots and fungi. An organism may have positive and negative effects on its neighbours. Mutualism: bird trefoil increases nitrogen availability for the grass. Competition: bird trefoil decreases light availability for the grass. Communities may experience a major disturbance, such as a forest fire.
