Download presentation
Presentation is loading. Please wait.
Published byHubert Stokes Modified over 9 years ago
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
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.