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Phenotypic Gambit Invoke Optimization of Behavior Mimic Assumed Stabilizing Selection Deduce Predictions From Hypothesized Currency of Fitness Specify.

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Presentation on theme: "Phenotypic Gambit Invoke Optimization of Behavior Mimic Assumed Stabilizing Selection Deduce Predictions From Hypothesized Currency of Fitness Specify."— Presentation transcript:

1 Phenotypic Gambit Invoke Optimization of Behavior Mimic Assumed Stabilizing Selection Deduce Predictions From Hypothesized Currency of Fitness Specify Quantitative Test

2 Model for Optimal Behavior Strategy Set: Possible Behaviors Find the “Best Strategy,” Given Hypothesis Constraints: Environmental, Physiological Define Problem Hypothesis: Behavior  Currency of Fitness

3 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

4 Standard (Simple) Optimization

5 a* Optimal Behavior?

6 Standard (Simple) Optimization a* Optimal Behavior?

7 Caveat Don’t Anticipate “Perfection” Naïve Pan-Selectionism Does Hypothesis Advance Understanding of Processes Shaping Diversity of Behavior in Nature

8 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

9 Crows Feeding on Whelks Northwestern crow (Corvus caurinus) Whelk (Thais lamellosa) Mollusc Search intertidal zone Fly to rocks, Drop prey Repeat, Shell breaks

10 Crows Feeding on Whelks Crows choose larger prey ~ Uniform size At rocks, Fly straight up, Drop whelk (Re-drop) Optimal foragers? “Optimize” H, height?

11 Crows Feeding on Whelks Number of drops versus height H Large prey break easier Constraint on problem

12 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

13 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

14 Deduce Prediction Derivative dE/dH = 0 H* = 5.6 m Minimizes cost

15 Prediction H = 5.6 m Mean close to H* Some variation Issue: Gain some understanding?


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