Relationships
, LT1
Evolutionary Explanations for Partner Preferences
NATURE OF SEXUAL SELECTION:
- Based on idea that competition for mates between individuals of the same sex affects the evolution of certain human traits
- Partner preference driven by sexual selection = choose partners to maximise reproductive success certain characteristics have
advantage over competitors for reproductive rights e.g. height, secondary sexual characteristics (puberty), hourglass = fertility
ANISOGAMY: means two sex cells that are different coming together to reproduce; male - sperm, female - agg/ova
- Sperm: small, highly mobile, created continuously, not a lot of energy required] no shortage of fertile males
- Egg: large, produced at intervals for a limited number of fertile years, lots of energy required] women are a rare resource
- Anisogamy is important as it gives two mating strategies; intra and inter sexual selection
INTER-SEXUAL SELECTION INTRA-SEXUAL SELECTION
● Preferred strategy of female - quality over quantity ● Preferred strategy of male - quantity over quality
● Trivers (72) → females invest more time and commitment for ● Competition between males to mate with a female
offspring = making a wrong choice of partner is more serious ● Winner reproduces and gets to pass on offspring
for the female = pays to be choosy characteristics
● Females lose more resources choosing a sub standard male ● To succeed, men must compete with other males to present
● Pick a partner who is fit willing to offer the max resources to themselves as the most attractive, encouraging features such
raise their offspring (protective) as muscles (indicate being protective)
● Females optimum mating strategy → select a genetically fit ● Dimorphism in humans → obvious difference between males
partner who is able to provide resources based on specific and females e.g. physical competition between males, size
characteristic e.g. Peahens choose peacocks with larger tails matters
so now mate more and pass characteristic on ● However females don’t compete for reproductive rights so
● Characteristics that maximise reproductive success are more there is no evolutionary drive towards favouring larger
likely to be passed onto subsequent generations and females
therefore partner preferences evolves a generation ● Behavioural and psychological consequences e.g. for males to
● Fisher (30): sexy sons hypothesis → female mates with a man acquire fertile females and protect them from competing
who has desirable characteristics and his ‘sexy’ trait is males, they must be aggressive
inherited by her son = increases likelihood that successive ● Minimal energy to produce sperm to fertilise everyday
generations of females will mate with her offspring women on earth and lack of post-coitally responsibility the
male carries
, LT1
Evolutionary Explanations for Partner Preferences
NATURE OF SEXUAL SELECTION:
- Based on idea that competition for mates between individuals of the same sex affects the evolution of certain human traits
- Partner preference driven by sexual selection = choose partners to maximise reproductive success certain characteristics have
advantage over competitors for reproductive rights e.g. height, secondary sexual characteristics (puberty), hourglass = fertility
ANISOGAMY: means two sex cells that are different coming together to reproduce; male - sperm, female - agg/ova
- Sperm: small, highly mobile, created continuously, not a lot of energy required] no shortage of fertile males
- Egg: large, produced at intervals for a limited number of fertile years, lots of energy required] women are a rare resource
- Anisogamy is important as it gives two mating strategies; intra and inter sexual selection
INTER-SEXUAL SELECTION INTRA-SEXUAL SELECTION
● Preferred strategy of female - quality over quantity ● Preferred strategy of male - quantity over quality
● Trivers (72) → females invest more time and commitment for ● Competition between males to mate with a female
offspring = making a wrong choice of partner is more serious ● Winner reproduces and gets to pass on offspring
for the female = pays to be choosy characteristics
● Females lose more resources choosing a sub standard male ● To succeed, men must compete with other males to present
● Pick a partner who is fit willing to offer the max resources to themselves as the most attractive, encouraging features such
raise their offspring (protective) as muscles (indicate being protective)
● Females optimum mating strategy → select a genetically fit ● Dimorphism in humans → obvious difference between males
partner who is able to provide resources based on specific and females e.g. physical competition between males, size
characteristic e.g. Peahens choose peacocks with larger tails matters
so now mate more and pass characteristic on ● However females don’t compete for reproductive rights so
● Characteristics that maximise reproductive success are more there is no evolutionary drive towards favouring larger
likely to be passed onto subsequent generations and females
therefore partner preferences evolves a generation ● Behavioural and psychological consequences e.g. for males to
● Fisher (30): sexy sons hypothesis → female mates with a man acquire fertile females and protect them from competing
who has desirable characteristics and his ‘sexy’ trait is males, they must be aggressive
inherited by her son = increases likelihood that successive ● Minimal energy to produce sperm to fertilise everyday
generations of females will mate with her offspring women on earth and lack of post-coitally responsibility the
male carries
