The Gene Propagation Game

Transcription

1 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

2 Zebras Are Rarely Alone Krogh (2005) Zebras live in groups, which may come together in large herds.

3 Honey Bee Communication

4 Playing Lion cubs Campbell & Reece (2002)

5 Meerkat Looking Out For Young Adults may be parenting their own offspring or babysitting the youngsters of a relative. Chris Johns

6 Musk Oxen Forming Defensive Circle Krogh (2005)

7 African Wild Dogs Campbell & Reece (2002) By hunting as a pack, predators may bring down prey much larger than themselves.

8 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

9 Males Fighting Over Females Male elephant seals fight over territory and harems of females. Winner takes all.

10 Wrestling Rattle Snakes

11 Macaque Shows Threatening Display

12 Gannet Birds Nesting in Small Territories

13 Cheetahs Mark Territories by Scenting

14 Chicken Show Dominance by Pecking

15 Chicken Pecking Order Krogh (2005)

16 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

17 Types of Altruism, defined as costly or risky behavior carried out by one individual to the benefit of another: Based on kinship Reciprocity Cultural selection kindness )?

18 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

19 Genetic Relatedness Coefficient The genetic relatedness coefficient ( relatedness ), r, is defined by the chance that a genetic allele of the focal individual (the one at the center of attention) is also present in a relative. For example, the relatedness between parent and child, and between siblings, is 0.5. Campbell and Reece (2002)

20 J.B.S. Haldane: I would give up my life for 2 brothers or eight cousins r to himself = 1 r to brothers = 0.5 r to cousins = 0.5 x 0.5 x 0.5 = siblings cousins

21 Hamilton s Rule Evolution will favor altruistic behavior if with C < B r C = cost (offspring lost) to altruist B = benefit (offspring gained) to beneficiary r = relatedness (chance that a genetic allele of altruist is also present in beneficiary)

22 Inclusive fitness simple fitness (own offspring) + indirect fitness (extra offspring of kin due to altruism, minus cost) benefit to kin in extra offspring must be weighted by the relatedness coefficient (r), whereas cost to focal individual in offspring lost is not weighted (because r = 1).

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24 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

25 Males and female reproductive strategies tend to differ cost of making gametes parental investment Kiwi eggs

26 Sea urchin egg being fertilized. Note size difference between egg and sperm.

27 Paternal Care in Seahorses The female inserts her ovipositor into the male s pouch, where she deposits her eggs, which the male fertilizes. The pouch acts like the womb of a female mammal. Most seahorses are monogamous for a breeding season. Pair bonds are reinforced by daily greetings in which the partners pirouette together.

28 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

29 Parental Care Is Gauged to Confidence in Paternity Photo: Mark Binkley The bluegill sunfish male gauges his paternal care to the presence of cuckolder males at spawning, and to the smell of newly hatched eggs.

30 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

31 Stag fight In many mammalian species, males fight to monopolize access to estrous females.

32 Infanticide

33 The Gene Propagation Game Social Living has Costs and Benefits Competition, Territoriality and Dominance Altruism in the Animal Kingdom Genetic Relatedness and Inclusive Fitness Mating Behavior Depends on Parental Investment Males Gauge Parental Effort According to Likelihood of Paternity Male Competition and Violence in Mammals

34 Types of Altruism in Animals Based on kinship Reciprocity Cultural selection ( kindness )?

35 Inclusive fitness encompasses the focal individual's simple fitness, plus the weighted increment in simple fitness of each relative aided by the focal individual, minus the cost of these altruistic acts to focal individual. k k FI = FS + dfr n r n - dfs n n=1 n=1 with FI, inclusive fitness of focal individual FS, simple (or Darwinian) fitness of focal individual k, number of relatives dfr n, increase in simple fitness of relative n r n, relatedness of focal individual to relative n dfs n, decrement in simple fitness incurred by focal individual as a result of aiding relative n

36 www2.biologie.uni-halle.de/zool/mol_ecol/

37 Selective Cannibalism Krogh ( 2005) Spadefoot toads eat smaller spadefoot toads, but let go if the caught individual is a relative.

38 Sperm Competition Damselfly and dragonfly males scoop out rival sperm

39 Infanticide