07ESS06x - Evolutionarily stable strategies (ESSs) Sex...

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Evolutionaril y stable strategies (ESSs)
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Sex ratiov - typical? why? - group - max. sp. productivity? - no, all ♀s mate (exceptions?) - so, min. ♂s! - individual? - population with 4 ♀s, 6 ♂s - if ♀ can choose offspring sex, what sex should she produce (optimally)?
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- if daughter, population now 5 ♀s, 6 ♂s - if all ♀s mate, on avg. produce 1/5 of population’s offspring - avg. ♂ sires 5/6*1/5 = 1/6 of offspring - if son, 4 ♀s, 7 ♂s - avg. ♂ sires 4/7* ¼ = 1/7 of offspring - sons ↓ value - population with 6 ♀s, 4 ♂s (you do the math) - sons ↑ value
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- pays to produce rarer sex - eventually, 50:50 best strategy - if alternate strategy can’t invade AND have ↑ success = ESS - evolved incapacity to alter sex ratio so now all play same strategy - ESSs now recognised as underpinning many behavs
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Kleptoparasitism - if behaviour adaptive, why not everybody? Strategy (% of pop., cals/hr) Generation Fishing Klepto . 1 100, 55 0 2 ~100, 54 110 3 70, 30 25 4 75, 35 25, 35 . - = mixed ESS - sp . not behaving optimally, individuals are!!
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This note was uploaded on 02/08/2010 for the course BIOL 3143 taught by Professor Daveshutler during the Winter '10 term at Acadia.

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07ESS06x - Evolutionarily stable strategies (ESSs) Sex...

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