Sexual selection Flashcards
1
Q
what are the two subtypes of sexual selection
A
inter-sexual selection (mate selection)
intra-sexual selection (competition)
2
Q
discuss generally the idea of altruism being sexually selected
A
- implies that altruism and cooperation are desirable for someone to reproduce with, not just desirable to help you
- so altruism must be displayed and observed (how? what about faking it?)
- both altruism and the preference for it would need to be genetically heritable - people who prefer altruists will mate with them and their children will inherit this preference and mate with altruists, driving a selection pressure towards altruism
3
Q
Todd & Miller 1998, sexual selection and altruism background
A
- fitness (survival and fecundicity) must be heritable and show individual variation
- natrual selection reduces varability, so need to focus on variable traits that can still be open to selection pressures (like attractiveness is)
- mate choice may favour phenotypic markers of good gene quality and parental investment
- choosing a mate relies on cues that advertise fitness (i na way that cant be taked)
- perhaps dont just look for cues in the individual but also in the phenotype of their relatives
4
Q
Miller & Todd (1998) two stage lens model (TICS)
A
- model that identifies cues we may use to find a good mate
- personality: kindness, generousness = trait agreeableness. is a key parameter we use to identify these cues. the say personality tells us about the capacity for a cooperative healthy relationship
- this suggests that certain traits are the basis of selecting a long-term mate
- and they take thi to mean that the preference for this trait and the trait itself are heritable
- so altruism could well be (is what im inferring here)
5
Q
sexual selection super-charging
A
- Miller 2007
- sexual selection can super-charge other evolutionary processes
- e.g. kin selection, reciprocity, and other group processes for altruism will become part of the sexual selection process, meaning they are morel ikely to be selected for
6
Q
parental investment and the sexual selection of altruism
A
- parental investment is crucial to both offspring survival and offspring mate choice
- in animals females invest a lot in offspring care so males show signals ad females choose
- in humans its now pretty equal so both males and females should show costly signals to attract mates
- males and females should display different types of signals because they have different investment traits
7
Q
good genes good partner good parents
A
- phenotypes may indicate all that stuff
- good genes correlate with fitness factors e.g. fecundicity, longevity, low mutation load (high IQ is linked to lower mutation load)
- good partner shows benefits for long term relationships e.g. loyalty, faithfulness, generousness
- good parents pass on traits for parental care e.g. feeding, protection, conflict resolution with siblings, teaching etc
- can these things be faked? i guess
8
Q
positive heritability and sexual selection
A
- miller 2007
- if the phenotype (altruism) is an indicator of good genes then it shoul be heritable
- ultimatium game responses are heritable with 42% of rejection behaviour being due to genetic factors. Wallace 2007
- trust game 20% investment and reciprocation due to genetic variation, Cesarini 2008
- Rushton 2004, prosocial attitudes are hertiable and genetic variation accounts for 50% of variance
- should also show a life history trend - it does - altruism is higher aftr puberty and in adults
9
Q
genetic inbreeding and parental age effects on sexual selection
A
- miller 2007
- altruism is lower with inbreeding - reflectinga small mutation load, so altruism may reflect a healthy varied gene pool and better immunity etc
- younger fathers should have more virtuous children (less sperm mutation)
10
Q
condition dependent costs and sexual selection of altruism
A
- have to pay cost of showing fitness but should be fitter and therefore altruistic traits should be associated with fitness outcome e.g. fertility, longevity etc
- evidence: Konrath 2012, other oriented motives for volunteering are related to living longer
11
Q
discuss sexual selection of altruism and how young adults are at their peak in trait expression
A
- young adulthood is where youd expect conspicuous displays of fitness to peak because thats when sexual actibity and presumeabley sexual selection are at their maximum
- study by your lecturer - 28,000 blood donors, showed blood donors without children are more likely to talk about donating than those with children. but this only held true during reproductive years. but could be something else? like perhaps they talked about it to raise awareness because they had no kids and wanted to help others futures? or people with children are dull and only talk about their kids? Ferguson (unpublished yet)
12
Q
discuss sexual derogation and sexua lselection of altruism
A
- miller 2007
- sexual rivals should derogate others with respect to generosity, altruism etc
13
Q
what is positive assortative mating,
A
- people attracted to others with the same traits
14
Q
so do people actually prefer altruistic traits in others?
A
- yes! but also lots of other things like attractiveness, intelligence
- single individiuals who engaged in more prosocial behaviour were more likely to be in a stable relationship 1 year on, e.g. Strvova & Ehlebracht 2015)
15
Q
is there evidence for assortative mating?
A
- yes but only for personality traits of O and C (McCrae 1996)
- Husbands who wanted kind and considerate wives were high high in A and C as were their wives
- but wives who wanted kind-considerate husband got those who were aloof, submissive and unmasculine apparently because sexism is a thig Buss and Barnes 1986
