emery_lecture_16 - Lecture16Predation

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Lecture 16 – Predation I. Trophic levels (feeding levels), guilds, food webs Food web: Trophic level: carnivores herbivores producers  competition within trophic levels (not considered in food webs) Predation: interaction in which one organism consumes all or part of another organism - different types of predators 1. true predator – catch and consume prey, removing them from population - consume several to many over their lifetime 2. grazers – eat parts of plants, don’t kill them (if eat plant entirely they are predator) - also attack several to many over their lifetime 3. parasites – consume parts of living organisms (host) - don’t usually kill prey (may in long run) - attack only one or very few hosts over lifetime - usually form very intimate relationship with host 4. parasitoids – usually wasps and flies - have larvae that consume tissues of living host from within - kill host like predator but only attack single host over lifetime (like parasite) II. Ecological effects of predation 1. effect on foraging ability of prey - study: p.afids suck nutrients out of plants, damsel bug sucks insides of p.afids  like a  predator - no predators on p-afids vs. adding predators that can’t eat them (no  mouth),  growth rate still declines because p.afids are afraid 2. effect on competitive ability of prey - study: daughter is a parasite to plants (like silly string)   takes all resources  from plant
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This note was uploaded on 04/11/2011 for the course BIO 585 taught by Professor R.howard during the Winter '08 term at Purdue University-West Lafayette.

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emery_lecture_16 - Lecture16Predation

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