6d. Sexual Selection: human mating strategies Flashcards
What are the negative aspects of sexual reproduction from an evolutionary viewpoint?
It is costly and transfers only 50% of DNA to offspring
Why bother with sexual reproduction?
The advantage of sex is increased VARIATION due to genetic recombination and mutation (asexual species don’t have this)
TRUE OR FALSE: Asexual species are more able to adapt and more complex.
False: Asexual species are LESS able to adapt and LESS complex.
Example of an asexual species and how it reproduces
Bacteria - a single cell splits into 2 daughter cells
TRUE OR FALSE: Most species reproduce asexually.
False: Most species reproduce sexually
How many mammal species are there?
4,300
How do most mammals’ sexual activity differ from humans?
Most mammals do NOT pair-bond or have nuclear families
Most often meet only to copulate
In most mammal species, females mate only in oestrus (sex is NOT recreational)
TRUE OR FALSE: Many animals only meet to mate and provide no paternal investment.
True
Harem mating systems
Dominant males (high testosterone) have bigger harems (and more offspring) Females are attracted to males with large territories
In what percentage of mammals does obligate monogamy (‘marriage’) occur? And what species is it common in?
5% of mammals
Common in birds
Why do humans have recreational sex?
May cement long-term pair bonds necessary for raising children
Concealed ovulation means a man does not know when his partner is not fertile
TRUE OR FALSE: Mating strategies vary between AND within species.
True
What is the difference between a ‘cad’ and a ‘dad’?
Cads have a large number of short term mating opportunities
Are women monogamous? Research
50% of married men had extra-marital sex (an affair)
26% of marries women has extra-marital sex by their forties
Little Kinsey
Britain, 1949 First UK nationwide sex survey 1/4 men admitted sex with a prositute 1/5 women admitted extra-marital sex Findings considered so outrageous they were suppressed
Polygamy has led to the evolution of…
jealousy (‘mate guarding’)
TRUE OR FALSE: Men and women experience equal amounts of jealousy.
True
What is different about the form jealousy takes in men and women?
Male jealousy - primed by their partner’s real/imagined SEXUAL infidelity
Female jealousy - primed by their partner’s real/imagined EMOTIONAL infidelity
Sex differences in jealousy - research
Ps imagined (a) their partner having sex with someone else, or (b) their partner becoming emotionally involved with someone else Men more distressed by sexual infidelity Women more distressed by emotional infidelity
Reason for sex differences in jealousy
Men - cuckoldry
Women - resources, parental investment
Major problem with research into infidelity and jealousy
Much research is based on IMAGINED infidelity
Jealousy triggers strategies of…
mate retention
Emotions and cognitions associated with jealousy
Fear
Anger
Sexual arousal / passion
Mate retention tactics include…
emotional manipulation submission physical signs of possession threatening/attacking competitors violence to partner love and care
TRUE OR FALSE: Fitness advantages of marriages are equally as obvious for men as for women.
False: Less obvious for men given high fitness variance
Why do many men commit to one woman, instead of trying to increase quantity of offspring?
> Big brained human babies require lots of parental care
Provides exclusive sexual access to one woman
Reproductive success depends more on mating with many women… e.g. children with paternal investment likely to fare better
Monogamy is common in _____ cultures
western
What is serial monogamy?
Having a series of monogamous relationships
What is polygyny?
1 male, more than 1 female
Monogamy increases the likelihood of…
lower quality males finding mates, but compromises female choice
Polygyny is not all bad for females
It may be more ‘suitable’ to be the 2nd wife of a successful male than the 1st to a poor one
What is polyandry?
1 female, more than 1 male
Why is polyandry much rarer than polygyny?
Tends to be in response to harsh environmental conditions
Why is polygamy the most suitable mating strategy for parental investment, theoretically?
Males seek high QUANTITY of partners, females seek high QUALITY of partners
TRUE OR FALSE: Monogamous species have less sexual dimorphism and difference among males.
True
Humans approximately __% sexual dimorphism, compared with >__% in gorillas
15%
> 50%
TRUE OR FALSE: Neither sex is entirely naturally monogamous.
True
