How two species can help, harm or ignore each other. Predation and the defences of prey, competition and the sharing of resources, parasitism, commensalism, amensalism and mutualism, each with its standard examples.
3 lessons, about 1 h 25 min3 simulations11 problems3 practice questionsPython in every lesson
Created by StemPy LabTwo species can help, harm or ignore each other, and a plus, a minus or a zero shows the effect on each. Predation is an interaction in which one species gains and the other loses. This lesson gives the roles of predators, the standard examples, the defences of prey, and the Lotka-Volterra cycle for A-Level and IB.
In competition, both species are harmed, because both need the same limited resources. Species that are not even related can compete. This lesson gives the competitive exclusion principle, the barnacles of the Scottish coast, competitive release, and the way in which species share resources to live together.
In parasitism, one species lives on or in another and harms it. In commensalism, one gains and the other is unaffected. In amensalism, one is harmed and the other is unaffected. In mutualism, both gain. This lesson gives each with its standard examples and the adaptations of parasites.
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