Lecture 7 Flashcards
What does selection favour?
Close kin over distant kin, distant kin over strangers
Who established the Theory of Inclusive Fitness?
W.D Hamilton 1964
What is the theory of inclusive fitness?
A reformulation of the theory of natural selection
What is too narrow a concept to explain natural selection?
Personal reproductive success (personal fitness, classical, fitness, Darwinian fitness)
What would selection favour?
Traits that cause an organism’s genes to be passed on regardless of whether the organism produces offspring directly (eg. by helping ‘kin’)
What is Hamilton’s rule?
That organisms can increase fitness not only by producing their own offspring but also by helping genetic relatives to survive and reproduce
What is inclusive fitness?
It is the sum of the direct individual reproductive success PLUS the indirect effect of that individual’s actions on the reproductive success of genetic relatives. So individuals will help others but that help is mostly directed towards relatives.
How does the percentage of lineage work?
Percentage of founder’s genes in each direct descendant halves with each generation
What does number of founder’s genes surviving in each generation equal?
The number of individuals in that generation carrying those genes x proportion they carry
To what percentage are you related to each of your parents and each sibling and child?
50%
What are the three values used to quantify the kin selection advantage?
The benefit to the recipient (B)
The cost to the altruist (C)
The coefficient of relatedness (r)
Kin selection favors altruism when rB > C
If sibling 1 inherits the allele from parent A, what probability is there that sibling 2 will also inherit this allele?
1/2, which means that the ‘r’ between the two siblings is 1/2 (0.5)
Universal aspects of kinship was a study done by..
Daly, Salmon and Wilson
What should all kinship systems display?
Ego-centred kin terminology (eg. my mother, my father)
Distinctions along the lines of sex and generation (eg. grandfather, grandmother, grandson, granddaughter)
Organisation by ‘closeness’ and latter by relatedness (eg. first cousin, maternal grandmother)
Self-concept based on position within kin network (daughter, son, brother, sister)
ALSO
Cooperation and solidarity on basis of relatedness
Encouragement of younger members by elders to help ‘collateral’ kin
Individual knowledge of ‘real’ (blood) relatives
Use of kinship terms to influence behaviour of non-kin
What did empirical tests: human patterns of help show?
That many more acts of helping towards close kin among kin, helping increased as function of recipient’s reproductive value eg. flow of help from older to younger
Who was more likely to survive on the titanic?
Women and particularly women in couples. Men in couples were less likely to survive.
What did the wealth inheritance and relatedness do?
Analyzed the bequests of a recent sample of 1000 dead people with probated wills - 552 men, 448 women in Canada
What was the median estate size, the smallest and the largest?
Median - 52,800
Smallest - 1000
Largest - 2, 075, 700
What percentage of these wills went to spouses, kin and non-kin?
36.9% to spouse, 55.3% to kin and 7.7% to non-kin
Who got most of the bequests apart from spouses?
Sons and daughters
What was the percent bequeathed to kin of 0.5?
46.5%
What was the percent bequeathed to kin of 0.25?
8.3%
What was the percent bequeathed to kin of 0.125?
0.6%
Who tends to distribute their estate more widely?
Women - normally mentioned with a qualifier such as ‘only if he remains unmarried’
What is the percentage of women who leave estate to spouse who have NO surviving biological children?
69%
What is the percentage of men who leave estate to spouse who have NO surviving biological children?
87.5%
What is the percentage of women who leave estate to spouse who have surviving biological children?
40.5%
What is the percentage of men who leave estate to spouse who have surviving biological children?
80.2%
Men who have a spouse and surviving children - how is the will divided?
About 70% to spouse, 22% to children
Women who have a spouse and surviving children - how is the will divided?
42% to spouse
48% to children
Men who don’t have a surviving spouse but do have surviving children - how is the will divided?
83% to children
Women who don’t have a surviving spouse but do have surviving children - how is the will divided?
87%
What does evolutionary theory predict about grandchild as genetic value?
Predicts some variability in grandparent investment in grandchildren arising from variation in the effect of paternity uncertainty
Who’s parents (mother’s or father’s) had higher results on the Gonsalkorale and von Hippel study?
Mother’s
To whom are kin relations more important?
Women
Who could recall more relatives in the test done between adult sibling pairs?
Sisters
Who is more likely to mention family role when asked who they are?
Females
To whom is the family name more important?
Males
What are the benefits of social organisation?
Reduction in predator pressure
Improved foraging efficiency
Improved defence of limited resources
Improved care of offspring
What’s the key feature of social organisation?
Cooperation
Why did cooperation evolve?
Because it conferred advantage
What is reciprocal altruism?
A successful getting food this week
B successful next
Both benefit from sharing
“Gain in Trade”
What is the prisoner’s dilemma?
Two prisoners held in prison for a crime they both committed.
If neither confess, both go free (R)
If both confess, both go to jail (P)
If A confesses and implicates B, A set free and gets reward (T)
If A doesn’t confess but is implicated by B, gets stiffer sentence than would have otherwise (S)
What is one of the most robust studies about reciprocal altruism?
Vampire bats of central America
What did the study show?
That vampire bats regurgitate blood meals to one another. Most of the episodes of regurgitation occurred between mother and child (75%) and the rest occurred between individuals with a close degree of association and relatedness. Not random.
What is a problem linked with reciprocal altruism?
The problem of deceit
What are the 5 requirements for social contract theory?
Ability to recognise many different individual humans
Ability to remember some aspects of history of interactions with each of these
Ability to communicate one’s values to others
Ability to model the values of others
Ability to represent costs and benefits, independent of items exchanged
