RELATIONSHIPS - evolutionary explanations for partner preferences

Question 1

what is sexual selection?

Answer 1

• evolutionary explanation of partner preference
• attributes or behaviour that increases reproductive success are passed on to offspring over successive generations

Question 2

who came up with sexual selection?

Answer 2

Darwin (1871)

Question 3

what is Anisogamy?

Answer 3

• difference between male and female gametes
  Male = sperm, small, highly mobile, created continuously in vast numbers
  Female = egg, large, static, limited number of fertile years
• leads to inter sexual and intra sexual selection

Question 4

what is one consequence of anisogamy?

Answer 4

no shortage of fertile male but fertile female is rarer

Question 5

Inter sexual selection?

Answer 5

• the strategies males and females use to select a partner.
• preferred strategy of the female, quality over quantity (ova are rarer than the sperm)

Question 6

Explain Trivers (1972)

Answer 6

A female’s mating strategy is to select a genetically fit partner to ensure that offspring are fit and resources are provided.

Males compete to be the fittest and most able to provide.

Question 7

Explain Fisher (1930) - sexy sons hypothesis

Answer 7

the genes that we see today are those enhanced by reproductive success. A female who mates with a man with a ‘sexy’ trait will have sons with that trait. The sons are more likely to be selected by successive generations of females.

Question 8

Intra sexual selection?

Answer 8

Selection of mates within sexes e.g. males competing against other males for mates.

Question 9

what happens as a result of intra sexual selection?

Answer 9

Sexual dimorphism, the differences in appearance between males and females of the same species, such as in colour, shape and size.

Question 10

what are the behavioural consequences of intra sexual selection?

Answer 10

the characteristics that are favoured and passed on are those that allow a male to outcompete his rivals.
eg males may benefit by behaving aggressively in order to acquire fertile females = this leads to selection of aggressive males.

Question 11

give strengths of research into evolutionary explanations for partner preferences.

Answer 11

+ RESEARCH SUPPORT FOR INTER-SEXUAL SELECTION.
Eg Clark + Hatfield (1989)
psych students approached other students at campus and asked them ‘ would you go to bed with me tonight?’
= females all rejected the request
75% of males accepted request
= supports view that females are choosier than males when selecting sexual partners.(supports Trivers’ hypothesis)

+ RESEARCH SUPPORT FOR INTRA-SEXUAL SELECTION.
eg Buss (1989) = 10000 adults completed a survey which showed that females placed a greater value on resource related charactersitics than males eg good financial prospects. Males values physical attractiveness and youth. = supports sexual selection theory

Question 12

give limitations of research into evolutionary explanations for partner preferences.

Answer 12

• cannot explain partner preferences of gay men and lesbian women. This is mainly because in homosexual relationships partners are not assessing genetic fitness. This lowers the value of sexual selection theory
• Evolutionary theories overlook the influences of social and cultural factors on partner preference= partner preferences influenced by rapidly changing social norms. eg women greater role in workplace = less dependent on men to provide for them.
  = partner preferences are likely to be consequences of evolutionary and cultural influences.