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Phenotypic Gambit Invoke Optimization of Behavior Mimic Assumed Stabilizing Selection Deduce Predictions From Hypothesized Currency of Fitness Specify Quantitative Test
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Model for Optimal Behavior Strategy Set: Possible Behaviors Find the “Best Strategy,” Given Hypothesis Constraints: Environmental, Physiological Define Problem Hypothesis: Behavior Currency of Fitness
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Basic Methods Predict Focal Individual’s Behavior: Does Behavior of Other Individual (s) Matter? Does Behavior of Other Individual (s) Matter? NO: “Standard Optimization;” Find Maximal Currency of Fitness YES: Game Theory; Find Evolutionary Stable Strategy
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Standard (Simple) Optimization
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a* Optimal Behavior?
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Standard (Simple) Optimization a* Optimal Behavior?
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Caveat Don’t Anticipate “Perfection” Naïve Pan-Selectionism Does Hypothesis Advance Understanding of Processes Shaping Diversity of Behavior in Nature
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Individual Behavior Crows Feeding on Whelks: references R. Zach (1978) Selection and dropping of whelks by Northwestern crowsR. Zach (1978) Selection and dropping of whelks by Northwestern crows, Behaviour, 67, 134 - 147 R. Zach (1978) Selection and dropping of whelks by Northwestern crows R. Zach (1979) Shell dropping: Decision-Making and optimal foraging in Northwestern crows,R. Zach (1979) Shell dropping: Decision-Making and optimal foraging in Northwestern crows, Behaviour, 68, 106 – 117 R. Zach (1979) Shell dropping: Decision-Making and optimal foraging in Northwestern crows,http://www-rohan.sdsu.edu/~jmahaffy/courses/f00/math122/lectures/optimization
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Crows Feeding on Whelks Northwestern crow (Corvus caurinus) Whelk (Thais lamellosa) Mollusc Search intertidal zone Fly to rocks, Drop prey Repeat, Shell breaks
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Crows Feeding on Whelks Crows choose larger prey ~ Uniform size At rocks, Fly straight up, Drop whelk (Re-drop) Optimal foragers? “Optimize” H, height?
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Crows Feeding on Whelks Number of drops versus height H Large prey break easier Constraint on problem
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Outline Model Hypothesis: Selection favors dropping whelk from height minimizing energetic cost to forager Individual Behavior: No Social Interaction Translate Height [H] into currency of fitness [Cost] Find H* where Cost minimal
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Model: E = kHN E: Energy cost (Currency) H: Drop height (Decision) N(H): No. drops k > 0 constant Objective Function a = 15.9; b = 1.2
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Deduce Prediction Derivative dE/dH = 0 H* = 5.6 m Minimizes cost
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Prediction H = 5.6 m Mean close to H* Some variation Issue: Gain some understanding?
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