Sexual Selection Flashcards

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1
Q

Who came up with the idea of sexual selection?

A

Darwin

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2
Q

Explain what natural selection is

A

Darwin explained evolutionary change in terms of natural selection - a characteristic that increases an individual’s ability to reproduce successfully must be highly adaptive and those with these genes will go on to produce successive generations, whilst weaker genes will die out

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3
Q

What are the problems with natural selection?

A

Some species have evolved characteristics that are positively detrimental to their survival, such as stags’ antlers and peacocks’ tails

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4
Q

What did Darwin come up with after natural selection to overcome the problems?

A

Sexual selection

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5
Q

Explain what is meant by sexual selection

A

If decorative characteristic increases the potential to reproduce then this is adaptive as they will have more offspring

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6
Q

What is sexual selection?

A

A key part of Darwin’s theory explaining how evolution is driven by competition for mates, and the development of characteristics that ensure reproductive success

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7
Q

What is anisogamy?

A

A type of reproduction where gametes of 2 sexes are dissimilar (in terms of size and number)

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8
Q

Explain anisogamy in terms of humans

A

Men produce millions of sperm with very little cost so their best strategy is to mate with as many females as possible to produce the maximum number of offspring. However, females produce 400 eggs in a lifetime, and huge biological cost during pregnancy and breast feeding so their best strategy is to be very discrimating and more selective as need good genes

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9
Q

How many eggs does a woman produce in a lifetime roughly?

A

400

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10
Q

What is intrasexual selection?

A

Mate competition (i.e. between males for females) - means the male who wins can pass his genes on to the next generation

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11
Q

What is intersexual selection?

A

Mate choice - the female is choosing which male to mate with

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12
Q

Outline short-term mating preferences for sexual selection

A

We possess a range of mating strategies evolved for short-term matin success - according to parental investment theory, men evolved a greater desire for casual sex, and would ideally seek sex earlier in a relationship

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13
Q

What did Buss (07) say about short-term mating for sexual selection?

A

Over the period of a year, a man who managed to impregnate a large number of females would have passed on more copies of his genes than a less successful male - but female who had sex with the same number of males in a year is likely to produce only one child - the less time a man permits to elapse before he has sexual intercourse with a woman, the larger number of women he can impregnate in a given time

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14
Q

What did Buss & Schmitt (93) say about short-term mating for sexual selection?

A

In contrast to women, men appear to lower their standard in the context of short-term mating - they also show a marked decrease in attraction following sex - evolved adaptation to bring about a hasty departure which prevents them spending too long with one woman

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15
Q

Outline long-term mating preferences for sexual selection

A

Both sexes typically invest heavily in any offspring so sexual selection favours high levels of choosiness in both sexes - as women have an obligatory biological investment in children, predicted to be very particular about their choice of mate, however males are also choosy

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16
Q

What does Buss (03) say about long-term mating preferences for sexual selection?

A

Females are attracted to males who are able to invest resources, able to physically protect and show promise as a good parent

17
Q

Name 3 positive evaluative points for sexual selection

A

1) Logical
2) Penton-Voak (1999)
3) Males’ preferences for younger women Buss (1989)

18
Q

Explain why sexual selection is logical

A

Although it takes time, energy and costs, random mating is stupid to produce attractive, healthy offspring of higher quality so genes are likely to be passed on

19
Q

Outline Penton-Voak (1999)

A

Female mate choice varies across menstrual cycle as they found women choose slightly feminised male ‘more attractive’ for long-term relationship which suggests kindness and cooperation in parental care but for short-term sexual relationships, during the high conception risk phase of the menstrual cycle, they preferred more masculine - higher levels of testosterone supresses the immune system so male healthy despite tis must have a highly efficient immune system - valuable characteristic

20
Q

Explain males’ preference for younger women for sexual selection

A

Buss (1989) - men have a distinct preference which can be explained in that younger women, have greater fertility - however others explained this in terms of social power as younger women are easier to control and so are preferred as mates

21
Q

Name negative 2 evaluative points for sexual selection

A

1) Mate-choice in real life

2) Gender differences - Clarke & Hatfield

22
Q

Explain mate-choice in real life for sexual selection

A

Studies like Buss’s might suffer from validity as they give an indication of expressed preferences instead of a reflection of what actually happens in real life - but, many real-life studies do support these mate-choice hypotheses like Buss (1989) who studied actual marriages in 39 cultures, supporting the idea that men do choose younger women

23
Q

Explain gender differences in short-term mating strategies for sexual selection

A

Clarke & Hatfield - provide evidence for gender differences in short-term mating preferences - men & women experiments asked stranger on a college campus whether they would have sex with them - 75% of men answered yes to having sex with a stranger whereas no women answered yes so found males more promiscuous hence supporting the idea of gender differences

24
Q

Explain one IDA point about sexual selection

A

Research consistently reports that men have more of a desire for a variety of sexual partners and greater willingness for casual sex, but men could never have evolved this desire in the absence of willing females - short-term mating carries a considerable potential cost to the woman but there could also be some benefits - for example leaving a poor-quality relationship or a way of producing more genetically diverse offspring - so explanations which emphasise advantages of short-term mating only to males offer a gender biased view of mating behaviour

25
Q

Outline Clarke & Hatfield (1989)

A

Provide evidence for gender differences in short-term mating preferences - men & women experiments asked stranger on a college campus whether they would have sex with them - 75% of men answered yes to having sex with a stranger whereas no women answered yes so found males more promiscuous hence supporting the idea of gender differences

26
Q

Name 5 research studies supporting sexual selection

A

1) Cartwright (2000)
2) Singh (1993)
3) Cunningham (1986)
4) Penton-Voak (2001)
5) Langlois & Roggman (1990)

27
Q

Outline Cartwright (2000)

A

Found women with symmetrical breasts are more fertile than more asymmetrically breasted women, thus supporting the idea that body symmetry indicates reproductive fitness

28
Q

Outline Singh (1993)

A

Used data from 50 years of beauty contest winners and playboy centrefolds to assess the waist-to-hip ratios of attractive women - found small waist and full hips consistent feature of female attractiveness, on average ratio was 0.7:1 - but breast size, overall body weight and physique varied

29
Q

Outline Cunningham (1986)

A

Examined the faces of males and females viewed as attractive by the opposite sex - found men preferred big eyes, fill lips, wide cheeks and a small nose which is neotonous but women preferred deep set eyes, high cheekbones and a chiselled jaw

30
Q

What does neotonous mean?

A

Looking like a baby

31
Q

Outline Penton-Voak (2001)

A

Found females prefer males with greater facial symmetry, which is an indication of development stability that would be passed on to her sons, increasing the reproductive potential

32
Q

Outline Langlois & Roggman (1990)

A

Found ‘average’ face viewed more attractive by babies as they looked at them longer - average faces tend to be symmetrical

33
Q

Name the key study for sexual selection

A

Buss (1989)

34
Q

What are the 2 aims of Buss (1989)?

A

1) Find sex differences in what we seek in a partner

2) Find out if there are any cultural differences

35
Q

What does Buss (1989) show?

A

Supporting evidence for universal sex differences in long-term mate preferences

36
Q

Outline the procedure of Buss (1989)

A

Asked a standardised set of questions to over 10,000 people in 37 different cultures

37
Q

What are the 5 questions asked in Buss (1989)?

A

1) Age, gender and marital status
2) What age want to marry?
3) What age partner like?
4) How many children?
5) How important 18 characteristics are… (rank them)

38
Q

What are the 4 finings of Buss (1989)?

A

1) All 37 men rated good looks more than women - research shown physical attractiveness provides cues to health and thus fertility and reproductive value
2) All 37 males and females preferred the male to be older
3) 36/37 women rated good financial prospects higher than men did - resources
4) Both males and females rated characteristics such as intelligence (parenting skills), kindness (interest in long-term relationships), and dependability (willingness to help a mate in times of trouble) as being desirable