Evolution&adaptation

Evolution&adaptation - EvolutionScorecard 21:35:00...

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Evolution Scorecard 21/10/2009 21:35:00 Industrial Melanism : Darwin’s Missing Evidence Kettlewell Involves peppermoths Dark moth and white moth (easily spotted) o Result of soot on trees during industrial revolution After pollution controls kicked in.. o Dark moth visible and white moth can’t be seen o Result of pollution controls after industrial revolution
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Units of Selection 21/10/2009 21:35:00 Individual Selection Genic Selection Richard Dawkins – The Selfish Gene Organisms are mere puppets, controlled by genes The hen is merely the  egg’s  way of making another  egg . – Samuel Butler The organism is merely the  gene’s  way of preserving the  genes . Group Selection Wynne-Edwards 1962 The Dillema\ o Individual selection: you should see fluctuating levels of organisms o Observed: population of deer was evenly matched as the amount of  the food resources Selection favors social behaviors that limit reproduction to avoid  overexploitation of available food resources o “conventional rewards” territoriality social dominance altruism The Essence of Group Selection A trait will evolve if: o Reproductive restraint  confers reproductive advantages on the entire  group o Selfish reproduction is disadvantageous to the group The Problem with Group Selection Consistent with individual selection
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Altruism: A Darwinian Paradox? 21/10/2009 21:35:00 Possible social Behaviors Based on the Effects of Relative Fitness of 2  Interactants
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You (behaver)    Friend (receiver)     Cooperation You work out and then so does your friend When you behave and decrease your fitness along with it decreasing your  friends ---Spite By decreasing your fitness to raise somebody else’s--- altruism Cooperative Hunting Harris Hawk Hunt in small groups 3 typical strategies: o successive pouncing o relay attack – one will attack, then another will attack, and so on o some flush prey; others ambush Cooperative Courtship Long-tailed manakins Females courted by alpha and beta males 2 males better than 1 o alpha advantage: Long-term Mating o Beta gains:
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Copulates when alpha absent If alpha disappears, beta now becomes alpha Cooperative Mobbing Ex: otters mobbing alligators Interspecific Cooperation Between two species Water snakes and yellow big trevali fish o Fish scare the prey into traps and snakes are able to catch the same  prey too b/c they can squeeze into the cracks the prey is trapped in.
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