BIO120H1 Lecture Notes - Lecture 23: Food Web, Cecum, Selective Breeding
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BIO120H1 Full Course Notes
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Document Summary
Tertiary consumers = carnivores who eat secondary consumers. Detritivores = organisms that eat dead, organic matter. Trophic connections among species can be analyzed as interactions webs with network properties like connectivity: food web. Trophic relations can determine community structure in ways that can be investigated by removal experiments: putting species in or taking species out, ex. Plants that grow in old fields (successional communities) + insects that eat such plants. Bugs are important to keep goldenrod species in check . Hairston, smith, and slobodkin (hss) (1960): trophic cascades . The world is greed because carnivores keep down herbivores don"t. Herbivores aren"t limited by plants, they"re limited by carnivores limit plant growth. Indirect effect: ex: one trophic level exerts influence on a second by affecting a third. Cascades involve effects that alternate across trophic levels. Lizards do benefit plans: unequal interaction strengths. Effect of lizards on spiders is weak. Lizards reinforce rather than counteract the effect of spiders.
