ENVS 3010 Lecture Notes - Lecture 7: Statistical Hypothesis Testing, Sample Size Determination, Statistical Power
21 Jul 2016
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What is a community: an ecological unit composed of populations of different species occupying a particular area, usually interacting with each other and their environment. Ex. bees pollinating flowers and taking pollen for themselves as well. Predation/parasitism: one species benefits and another is negatively effected, usually one species feeding on another. Competition: when 2 species coexist and compete for resources they do not do as well as they would alone. Amensalism: one species is negatively affected and the other is not affected at all. Ex. sheep trampling the grass, are harming it but they are not effected. Commensalism: one species is positively affect and the other is not affected at all. Ex. shadow feeders who follow sharks get to feed without affecting the shark. Indirect interactions: interactions mediated by a third species, trophic cascade. Ex. aphid preys on grass, parasite feeds on aphid, therefore presence of parasite has a positive effect on the plant: apparent competition.
