BIOLOGY 1M03 Chapter Notes - Chapter 53: Biogeography, Lignin, Soltyrei
8 Sep 2014
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Document Summary
A biological community consists of interacting species, usually living within a defined area. To study species interaction, biologists focus on analyzing the effects on the fitness of individuals involved. Four categories of interaction: -/- relationship known as competition, +/- relationship known as consumption and parasitism, +/+ relationship termed mutualism, +/0 relationship termed commensalism. Birds that follow moving army ants in the tropics. As ants march along forest, they hunt insects and small vertebrates. As they do, birds follow and pick off prey species that fly or jump out of the way of the ants. The birds are commensals that benefit from the association (+), but have no measurable impact on the ants (0) Section focuses on three key themes: species interaction may affect the distribution and abundance of a particular species. Changes in species interactions often explain short-term changes in population size and distribution: species act as agents of natural selection when they interact.
