Relationships: Sexual selection and Evolutionary behaviour Flashcards
Sexual selection
Evolutionary process in which physical and psychological qualities (that resulted in greater reproductive success) become more common across species
Anisogamy
Difference between male and female gametes
Anisogamy: males
Sperm: Small, mobile, continuously produced
Anisogamy: female
Ova(egg): Large, static, produced in intervals for limited number of years
Consequences of anisogamy
Plenty fertile males, fewer fertile females
Gives rise to different mating strategies
Inter-sexual selection
Selection of mates between sexes.
Each sex has innate preferences for a mate with certain characteristics
The preference determines area in which other sex must compete
Which gender prefers inter-sexual selection?
Females bc quality over quantity
Female strategy
Females make a greater investment of time and commitment before, during, and after birth of offspring
Seeks male that will provide healthy offspring, support them w resources
Female makes biological investment in the child, thus looks for good resources
Female strategy: what do females seek?
A male that will:
Provide healthy offspring
Support them with resources
Physical strength in male
Inter-sexual selection: factors impact on human reproductive behaviour
Preferences of both sexes determine attributes that are likely to be passed on (e.g. females preferring taller men (height))
Overtime, leads to characteristic becoming more evident in males - the runaway process
Runaway process
Likelihood of a characteristic becoming more evident overtime in a gender, as it is preferred by the opposite gender.
The runaway process happens…
Overtime
Intra-sexual selection
Competition among members of same sex, for members of opposite sex
Which gender prefers intra-sexual selection?
Males bc quantity over quality
Male strategy
Competition is necessary because females are a limited resource and a choosy
Victors can pass the genes to the next generation and therefore those traits which lead to their success are maintained
Intra-sexual selection: factors impact on human reproductive behaviour
Intra-sexual selection pressures -> certain patterns of human behaviour:
Male aggression
Male preference for youthful and fertile women
Male desire
Male aggression
Male act aggressively = more likely to succeed in mating bc more likely to win competition against another male
Male preference for youthful and fertile women
These characteristics are a better guarantee of reproductive success
Therefore genes of those males with these preferences = more likely to be passed on to their offspring = successful mating strategy
Male desire
Fuckboy: Male desire to optimise mating chances by fertilising as many female as possible
Male desire: evolutionary theories
Fuck and chuck. Say that men decrease sexual attraction following sex to prevent spending too much time with any one woman
A03: support for relationship between intra-ss and human reproductive behaviour
Buss (1989)
Conducted survey on partner preference using over 10,000 adults in 33 countries
A03: Buss 1989: procedure
Conducted survey on partner preference using over 10,000 adults in 33 countries
A03: Buss 1989: findings
Females value resource-related characteristics (ambition, financial prospects) more than males
Males value reproductive capacity ( physical attractiveness, younger women bc fertility) more than women
Resource-related characteristics
Ambition
Financial prospects
Reproductive capacity
Younger women bc more fertile
Physical attractiveness
A03: Buss (1989) culture advantage
33 countries suggests universality
Supports:
sex differences due to anisogamy
partner preference derived from sexual selection theory
A03: Buss (1989) culture disadvantage
Wasn’t truly cross cultural study
Hard to include rural population
Not a proper sample within a country, as results reflect people from cities, not rural areas
A03: Against Buss: alternative reason as to why men prefer younger women
Preference due to social power; younger = easier to control
A03: against alternative as to why men prefer younger women
Kenrick et al
Found teenage males prefer women 5 years older than them
These women not easily controlled
Support evolutionary explanation
A03: Buss supports
Intra-sexual selection and human reproductive behaviour
A03: Support for inter-ss and human reproductive behaviour
Support for claim males seek ST mating opportunities
Clark and Hatfield (1989)
College campus study - see whether females and males willing to have sex with attractive stranger
A03: Clark and Hatfield findings
0% females agreed - suggests female choosiness exists
75% males agreed - males evolved different strategy for reproductive success
A03: Singh et al. SO what?
Evolutionary factors reflected through
patterns of human reproductive behaviour through
partner preference
A03: support Singh et al waist:hip ratio
Measured males preference for females waist hip ratio
Hip size attractive if ratio of one to the other is 0.7
Signifies fertility and not currently pregnant
A03: against. Chang et al. Findings
Report some preferences have changed, some remained same over 25 years in China
A03: against. Chang et al. SO what?
Suggest both evolutionary and cultural influences must be taken into account when explaining human reproductive behaviour
A03 1/2 support for inter-sexual
Penton-voak
Fertile: masculine faces (virility, good genes) ST mating desirable for offspring
Less fertile: feminine faces (kind, cooperative) LT partner
