Animal Social Behavior

Animal Social Behavior levels of biological organization?

Is family important?

Animal Social Behavior

Animal Social Behavior Konrad Lorenz V.C. Wynne-Edwards Sewall Wright W.D. Hamilton

Animal Social Behavior genetic relatedness? average proportion of genes shared by common descent between any two individuals “coefficient of genetic relatedness” “r”

Animal Social Behavior How is genetic relatedness determined? 0.5 Becky -- Steve Charles -- Deborah Chris Jeff Rachel Lauren 0.5 0.5 Siblings: 0.5 parents/offspring: 0.5 Aunts/uncles with nieces/nephews r = 0.25 (0.5 x 0.5) first cousins r = 0.125 (0.5 x 0.5 x 0.5)

Animal Social Behavior “indirect selection” “…selection may be applied to the family as well as to the individual…”

Animal Social Behavior Heritable variation differential RS spread of characteristics adaptive behaviors… indirect selection Heritable variation (among families, in behaviors that promote inclusive fitness) combined with differential RS (among families) leads to the spread of characteristics (that increase inclusive fitness) through populations adaptive behaviors may evolve due to the action of indirect selection

Animal Social Behavior Costs, Disadvantages Benefits, Advantages competition… diseases, parasites degradation of environment increased conspicuousness… efficiency of foraging, predation… sharing information avoidance of predation opportunity to modify environment interaction with genetic relatives

Animal Social Behavior Costs, Disadvantages competition… diseases, parasites degradation of environment increased conspicuousness… Benefits, Advantages competition… efficiency of foraging, predation… avoidance of predation sharing information opportunity to modify environment interaction with genetic relatives