Sexual Selection

Question 1

Who came up with the idea of sexual selection?

Answer 1

Darwin

Question 2

Explain what natural selection is

Answer 2

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

Question 3

What are the problems with natural selection?

Answer 3

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

Question 4

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

Answer 4

Sexual selection

Question 5

Explain what is meant by sexual selection

Answer 5

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

Question 6

What is sexual selection?

Answer 6

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

Question 7

What is anisogamy?

Answer 7

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

Question 8

Explain anisogamy in terms of humans

Answer 8

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

Question 9

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

Answer 9

400

Question 10

What is intrasexual selection?

Answer 10

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

Question 11

What is intersexual selection?

Answer 11

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

Question 12

Outline short-term mating preferences for sexual selection

Answer 12

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

Question 13

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

Answer 13

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

Question 14

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

Answer 14

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

Question 15

Outline long-term mating preferences for sexual selection

Answer 15

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

Question 16

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

Answer 16

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

Question 17

Name 3 positive evaluative points for sexual selection

Answer 17

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

Question 18

Explain why sexual selection is logical

Answer 18

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

Question 19

Outline Penton-Voak (1999)

Answer 19

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

Question 20

Explain males’ preference for younger women for sexual selection

Answer 20

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

Question 21

Name negative 2 evaluative points for sexual selection

Answer 21

1) Mate-choice in real life

2) Gender differences - Clarke & Hatfield

Question 22

Explain mate-choice in real life for sexual selection

Answer 22

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

Question 23

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

Answer 23

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

Question 24

Explain one IDA point about sexual selection

Answer 24

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

Question 25

Outline Clarke & Hatfield (1989)

Answer 25

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

Question 26

Name 5 research studies supporting sexual selection

Answer 26

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

Question 27

Outline Cartwright (2000)

Answer 27

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

Question 28

Outline Singh (1993)

Answer 28

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

Question 29

Outline Cunningham (1986)

Answer 29

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

Question 30

What does neotonous mean?

Answer 30

Looking like a baby

Question 31

Outline Penton-Voak (2001)

Answer 31

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

Question 32

Outline Langlois & Roggman (1990)

Answer 32

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

Question 33

Name the key study for sexual selection

Answer 33

Buss (1989)

Question 34

What are the 2 aims of Buss (1989)?

Answer 34

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

2) Find out if there are any cultural differences

Question 35

What does Buss (1989) show?

Answer 35

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

Question 36

Outline the procedure of Buss (1989)

Answer 36

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

Question 37

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

Answer 37

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)

Question 38

What are the 4 finings of Buss (1989)?

Answer 38

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