Evolution and Social Behavior Flashcards
Adaptation vs Evolution
short-term change(microevolution) vs long-term change(macroevolution)
What is the primary mechanism of biological change over time
Natural Selection, proposed by Darwin in 1859
3 fundamental facts of natural selection
*Variation - Differences between and within species
*Inheritance - Traits passed from parents to offspring
*Overproduction - More offspring are born than can survive
How does survival relate to reproduction in evolution
Survival alone is not enough; reproduction is key to passing on adaptations
fitness
an individual’s ability to reproduce successfully compared to others in the species
relationship between adaptation and evolution
*Traits well-suited to an environment increase in frequency over generations
*Traits that reduce survival/reproduction decrease in frequency
How does natural selection operate on populations vs individuals
Population: Evolution occurs over generations
Individual: Natural selection determines survival and reproduction
What is sociobiology
Application of evolutionary principles, specifically natural selection, to behaviour
Altruistic behaviour in primates
*predator alarm calls
*Defending a group member
*Sharing food/caring for infants
Altruism and natural selection
Natural Selection favours traits that increase reproductive success, while altruism may reduce it
What is group selection and why is it rejected
*The idea that altruism benefits the survival of the group
*Rejected because selfish individuals have higher reproductive success
How does kin selection explain altruism
Helping relatives indirectly passes on shared genes, increasing inclusive fitness
Kin selection
*Natural selection can operate on genes rather than individuals
Inclusive fitness
Individual’s fitness + effect upon the fitness of relatives
Hamilton’s rule
Altruism is favoured when C < B x R
*C = cost to actor’s fitness
*B = benefit to recipient’s fitness
*R = degree of relatedness(fraction)
What is reciprocal altruism
Helping non-relatives with the expectation of future help in reutrn
Conditions for reciprocal altruism
*Frequent social interactions
*Helping individuals are of similar abilities(rank, size, etc.)
What is mutualism and how does it differ from altruism
benefits both parties with no cost to the actor
Why do primates form groups(benefits)
*Better access to resources
*Protection from predators
*Increased mating opportunites
*Social benefits(grooming, coalition support)
Costs of group living
*Intra-group competition for food/mates
*Increased disease transmission
What behaviours show strong social relationships in primates
*grooming
*Huddling
*Coalition support
*Tolerance when feeding
3 main types of dispersal
*Male-biased: males leave; strong FF bonds
*Female-biased: females leave; strong MM bond
*Both-sex: both leave OR stay: Fs bond to alpha male
Parallel dispersal
Individuals emigrate together or into groups with familiar individuals
Benefits of parallel dispersal
*Easier group integration
*Maintains ties with relatives
*Increased survival during transfer
R value in Hamilton’s rule
*0.5 for parents, siblings, children
*0.25 for grandparents, grandchildren, aunts/uncles, nieces/nephews
*0.125 for great grandparents, great grandchildren, great aunts/uncles, cousins
Example of Male biased group
Cercipithecines(baboons, macaques)
Example of female biased groups
Chimpanzees, Red colobus
Examples of both sex dispersal
Black and gold howlers, black and white colobus
Usrine colobus dispersal
*All males disperse, some females disperse
*Both sexes show parallel dispersal
