What is the Wynne -Edwards and the reproductive restraint about?
reproductive restraint = when no food animals lay less eggs
- when less food available = animal becomes stressed (competition)
- lead to population dies out
What does the Evolutionary stable strategy say?
it says that altruism is not a stable strategy and selfishness will always out-competes altruistic animals
- the average fitness of selfish alleles is higher vs. altruistic ones
- selfish allele = fixation
- altruistic = extinct
- in a Population which goes extinct the selfish allele has twice the fitness as altruistic ones
What is Kin selection?
helping relatives
What is the theory of Kin selection by Hamilton?
helping according to Hamilton occurs:
if the relatedness and the reproductive success is bigger than the cost of helping
r x b > c
r = coefficient of relatedness (0,5 by siblings, 0,25 by nephew)
b = benefit of helping
(how many more offspring produced)
c = cost of helping
(how many fewer offspring produced)
What is altruism?
- helping other that may can involve own cost
- positive to the other but negative to oneself
What is mutual -benefit behaviour?
- when everyone benefit of it
- the behaviour positively affects the lifetime reproductive success of the receiver and also positively affects reproductive success of oneself
What is the By-product benefit?
e.g. deer
- when the benefit of others arise out of a side-effect of the actors benefit
- no cheating problem (you cannot take the benefit of being in the group without bearing the cost of being in the group)
E.g. deers in a group dilutes the risk of predators, each deer benefits and each individual by itself too
What is direct reciprocity?
we help individuals that help us
“I scratch your back, when you scratch mine”
-possible with time delay, but one need to know that it is not a single meeting
c < w x b
w = probability of the receiver to reciprocate in the future b = benefit to the receiver c= the cost of the behaviour must always be the smallest
Indirect reciprocity
helping individuals who have been seen or heard about helping in the past
- even if the help was not specifically directed to you
- all about good reputation
c < q x b
q = the probability of having the correct information about the other
Punishment, another mechanism that can make cooperation stable
- punishing the cheater, even if it is high costly
(individuals will be punished for not cooperating) - the presence of punishment lead cooperation to increase
What is Eusocial society? (article)
- an extreme form of altruism
- queen produce offspring, while (temporarily) sterile worker bees care for offspring
- haplo-diploidy produces unusual coefficients of relationships
- indirect fitness benefit by helping the offspring
- sister bees have 0.75 relatedness, which is higher than producing own offspring
What are the 4 main criteria in eusocial societies?
- Overlapping generations
- multiple generations live together - cooperative brood care
- when individuals other than parents assist raising offspring (e.g. sisters) - Philopatry
- when individuals remain living in their birthplace - Reproductive altruism
- extreme form
- when one self not reproduce but help family members
What is inclusive fitness?
The combination of direct fitness + indirect fitness
direct fitness = number of own offspring
indirect fitness= number of relative offspring)
Pathogenesis in male bee’s (Eusociety)
pathogenesis means that the males come from an unfertilized egg and thus only have one set of chromosomes
Example for proximate and ultimate explanation by an infant crying
Ultimate explanation (why) = elicits care and defense from mother
proximate explanation (how) = the external trigger of crying (physical separation of caregiver) and also the internal mechanisms (limbic system)
why can parochial altruism explain war?
Parachialism = favoring own ethnic, racial
altruism = benefit others at a cost to oneself
=> both together lead to in-group favorism and provoke conflicts between groups
=> hostility against out-group, when resources scare e.g. war
experiment with eyes or flowers on the donor box
- people tend to donor more when there are eyes on the box, because they feel like they are seen
- humans are also more sensitive to facial elements especially eyes
What is group selection?
Group selection
- pure cooperator groups grow fast
- selection within group favors defectors (social loafing)
- selection between groups favors cooperators
What is network reciprocity?
Network reciprocity
-> creating networks and helping people in own network
