Ch13-the Evolution of Social Flashcards
Does social life entail being “higher up” on the evolutionary ladder?
No. In some cases living alone is superior to living together when the cost-benefit ratio is better for solitary rather than social individuals. (competing for social status is costly)
List the costs of social living.
- greater conspicuousness
- greater transmission of disease and parasites
- more competition for food among group members
- time/e expended by subordinates in dealing with dominants
- greater male vulnerability for cuckoldry
- greater female vulnerability to egg tossing and repr. interference
List the benefits of social living.
- dilution effect and mutual defense=defense against predators
- opportunities to receive help to deal with pathogens
- improved foraging
- subordinates are granted permission to stay in group
- chance to cuckold others
- opportunity to interfere with rivals’ reproduction via egg dump etc.
Explain the four different categories of helping behavior.
- mutualism-shared gain of direct fitness (lion pride captures prey)
- reciprocity-delayed gain of dir.fitness (vampire blood exchange)
- facultative altruism-temporary loss, potential for indirect then personal gain (florida scrub jay, help parents then get territory)
- obligate altruism-permanent loss DF, potential for indirect (honey bees workers foraging for colony
Define: reciprocity and indirect reciprocity.
Helpful action is repaid at a later date by the recipient of assistance. AKA reciprocal altruism
Ind. A form of reciprocity in which a helpful action is repaid at a later date by individuals other than the recipient of assistance.
What is the significance of the prisoner’s dilemma?
Reciprocal cooperation should never evolve. But it did because two players interact repeatedly, not just once as indicated by the prisoner’s dilemma.
Define: altruism.
Helpful behavior that raises the recipient’s direct fitness while lowering the donor’s direct fitness.
Define: coefficient of relatedness,
The probability that an allele present in one individual will be present in a close relative; the proportion of the total genotype is present in the other, as a result of shared ancestry
How could altruism could have arisen?
Helping genetically similar individuals (relatives) survive to reproduce can provide increase in indirect fitness because it is propagating similar alleles.
Define: indirect selection and kin selection
Indirect-The process that occurs when individuals differ in their effects on the survival of nondescendant kin, creating differences in the indirect fitness of the individuals interacting with this category of kin.
Kin-affects parental care/helping behavior for offspring or nondescendant kin
Define: hamilton’s rule.
(coef of relatedness)(# of niece/nephews) B must be more than (0.5)(# of offspring)C
Or rB>C
Define: haplodiploidy.
a sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid
Define: transactional theory.
The view that social units form as a result of the ability of individuals to negotiate for reproductive opportunities with one another. Concessions model- dominant members of group concede some reproductive rights to others in return for their cooperation while staying with the group.
Define: eusociality.
A social system in which specialized non-reproducing castes work for the reproductive members of the group.
How could eusociality develop if many sisters are not closely related due to polyandry?
It is likely eusociality developed before polyandry evolved when sister’s were more closely related. Current selection pressures of eusociality differ from previously. Polyandry-promote disease resistance or worker specialization.
