25. Species interactions - predation & mutualsim skeleton Fall 2007

25. Species interactions - predation & mutualsim skeleton Fall 2007

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1 How do predator/prey or host/parasite interactions affect populations and communities? Final Exam Dec. 11 Tues 12:20 – 2:10 Discussion Board ends Wed at 5 pm
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2 And Predation Isn’t Limited To Animals …
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3 Like competition, predation/parasitism/disease may affect populations and communities Interaction Predator Effect on Prey or Host Prey or Host Effect on Predator/parasite Predation, parasitism, disease Negative (-) Positive (+)
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4 First, how do predators and prey affect populations sizes? We might expect that predator and prey populations follow each other We might predict that some predators, if efficient, can drive prey to extinction Theory (based upon logistic equations) predicts this (we won’t explore this …) Experiments and observations confirm this
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5 Simple Lab Experiments … Time Number of predators or prey Prey Predator 0
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6 A Bit More Complex Lab Experiments Some oscillations before extinction …
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7 More Complex Greenhouse Experiments … More oscillations of predator-prey … Cyclamen mites – 1 predator, 1 prey spp.
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8 Simple Lab Experiments … Predators quickly cause extinction unless heterogeneity is added to system Heterogeneity may include: 1. immigration/emigration 2. Prey refuge (in space or time) 3. Variation in prey defenses 4. More species or predator or prey
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9 Real World Observations … Hare (prey) and lynx (predator) Long-term data from Hudson Bay fur records Show distinct 9-11 cycles …
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10 Real World Observations … Fig. 55.4
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This note was uploaded on 04/02/2008 for the course BIO 187 taught by Professor Douglasgreen during the Spring '07 term at ASU.

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25. Species interactions - predation & mutualsim skeleton Fall 2007

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