1. Kin selection

2. actor +- + cooperativealtruistic - selfishspiteful recipient Individual interaction behaviors

3. altruism presented a “special difficulty, which at first appeared to me insuperable, and actually fatal to my whole theory.” Darwin 1859

4. ‘Altruisitc’ interactions Manipulation Individual advantage Reciprocal altruism Kin selection

5. Manipulation nest parasitism brown headed cowbird

6. Individual advantage fish schooling selfish herd

7. Reciprocal altruism can evolve only under a restricted set of conditions A will help B, if B will help A in the future Need: -repeated interactions -individual recognition Reciprocal altruism grooming

8. Vampire bats reciprocate by sharing blood meals. They usually share with close relatives or non-relatives who are roostmates and may later reciprocate Reciprocal altruism

9. Most alleles favored by kin selection rise to high frequency by inducing altruism toward individuals likely to be carrying copies of the same allele Selection can favor making sacrifices for kin; it should also favor avoiding sacrifices for non-kin Kin selection

10. Inclusive fitness consists of direct fitness due to personal reproduction and indirect fitness due to additional reproduction by relatives Inclusive fitness = direct fitness + indirect fitness Behavior that results in indirect fitness gains is favored by kin selection Inclusive fitness

11. 0.5 Coefficient of relatedness parent-child 0.5 0.25 + 0.25 = 0.5 full siblings 0.5 0.25 half siblings 0.5 0.25 grandparent - grandchild 0.5 0.5 x 0.5 x 0.5 = 0.125 cousins

12. Helpers gain indirect fitness benefits because they are very closely related to their siblings Helpers at the nest Florida scrub jay

13. Helpers at the nest White-fronted bee-eater

14. Helpers at the nest White-fronted bee-eater

15. Alarm calling Belding’s ground squirrels

16. Alarm calling Belding’s ground squirrels

17. Alarm calling Meerkat sentinels Science, June 04 1999, 284: 1585

18. Cannibalistic tadpoles Spadefoot toad tadpoles omnivorous morph carnivorous morph

19. Parents maximize their fitness by investing in all of their offspring equally Offspring, in contrast, maximize their fitness by receiving more parental investment than their siblings

20. Siblicide may increase the fitness of parents as well as the siblicidal offspring if the offspring that is killed is likely to die anyway Siblicide

21. Siblicide - adelphophagy Sand tiger shark Intra-uterine embryonic cannibalism

22. Eusociality

23. 3 characteristics: overlap in generations between parents & offspring cooperative brood care specialized castes of non-reproductive individuals

24. In haplodiploid species females are more closely related to their sisters than they are to their own offspring (0.5 x 0.5) + (1 x 0.5) = 0.75 sisters 1 0.5 mother diploid father haploid (0.5 x 0.5) = 0.25 brothers Eusociality

27. haplodiploidy does not completely explain the evolution of eusociality many eusocial species are not haplodiploid many haplodiploid species are not eusocial

28. Eusociality naked mole rats