BIO120H1 Lecture Notes - Lecture 10: Cardiac Glycoside, Cecum, Aposematism
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BIO120H1 Full Course Notes
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Document Summary
Secondary consumers carnivores who eat herbivores. Tertiary consumers carnivores who eat secondary consumers. Trophic connections among species can be analyzed as interaction webs with network properties like connectance . Food chain where only one organism eats the previous organism. Food web a web of producers and consumers. Trophic relations can determine community structure in ways that can be investigated by removal experiments. Relationship between diversity and the trophic levels. The world is green because carnivores keep down herbivores so herbivores don"t limit plant growth. Example of an indirect effect: one trophic level exerts influence on a second by affecting a third. Cascades involve effects that alternate across trophic levels. Lizards eat spiders, herbivores, spiders eat herbivores. But the effect of lizards on spiders is week, while their effect on herbivores is strong. So lizards reinforce, rather than counteract the effects of spiders, and thus has a positive indirect effect to the plants.
