1. Animal Social Behavior

3. Animal Social Behavior
levels of biological organization?

4. Is family important?

5. Animal Social Behavior

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

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

9. 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 = (0.5 x 0.5 x 0.5)

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

11. 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

12. 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

13. 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