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BIO 416 Evolution. Lecture #21 Kin Selection & Altruism March 6, 2009. Dr. Karen Schmeichel Oglethorpe University. Business:. Essay #2 Adaptation (due) Lit Review #3 Due 3/9 Airtran trip update Exam II 3/13 – Lab exercise too Ch 12: 447-478 Kin Selection. Objectives:.
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BIO 416Evolution Lecture #21 Kin Selection & Altruism March 6, 2009 Dr. Karen Schmeichel Oglethorpe University
Business: • Essay #2 Adaptation (due) • Lit Review #3 Due 3/9 • Airtran trip update • Exam II 3/13 – Lab exercise too • Ch 12: 447-478 Kin Selection
Objectives: • Explore choosiness: What’s the benefit? • What happens when females are competitive? • Discuss altruism (a difficulty for Darwin) and indirect fitness
A Simple Assumption One sex: “competitive” Other sex: “choosy”
Gray Tree Frog Serenade http://www.mister-toad.com/photos/frog/hyla_versicolor_05.html
What’s the Attraction? What do these advertisements tell the “choosy” mate? • Fitness/Gene Indicator • Food Acquisition • Sensory Biases • Sexy-son Hypothesis
Direct Caloric Benefits
When the Females Experience Sexual Selection: (i.e.,females are competitive) Polyandry
Anglerfish: An extreme case of Sexual Dimorphism
Other Evolved Behaviors Kin Selection & Social Interactions
Hamilton’s Coefficient of Relatedness “r”: The probability that Homologous alleles in two individuals are identical by descent
Computing “r” with pedigrees The “Got from”/ “Give to” Approach
Hamilton’s rule: an allele for altruistic behavior will spread if: Br-C>0 more likely if benefits to recipient are great and the cost to the actor is low and the participants are closely related
Kin Selection: Natural selection favoring the spread of alleles that increase the indirect fitness
For 3/9: • Ch 12: 447-478 • Kin Selection II • & Lit review #3