Relationships - Sexual Selection and Human Reproductive Behaviour

Question 1

Why might certain seemingly disadvantageous characteristics still be passed on to the next generation?

Answer 1

These characteristics may be advantageous for sexual selection. For example males who behave aggressively have a greater chance of protecting their female from competing males. And females with traits of fertility such as wide hips and a narrow waist.

These traits may seem like a disadvantage but from an evolutionary pov they are the opposite.

Question 2

What does sexual selection determine?

Answer 2

Determines which genes are passed onto offspring , through the process of heredity.

Question 3

What does the term ‘anisogamy’ describe?

Answer 3

The idea that there are differences between male and female gametes.

Question 4

What could some differences between male and female gametes be in terms of?

Answer 4

In terms of:
- Size of gametes
- Energy invested into their production
- Whether they are static or mobile
- The intervals at which they are produced

Question 5

What are the differences between m&f gametes reflected in?

Answer 5

Reflected in the two types of sexual selection and which is preferred by each gender.

Question 6

What are the two types of sexual selection?

Answer 6

Intra-sexual selection
Inter-sexual selection

Question 7

What type of sexual selection do females favour?

Answer 7

Inter-sexual selection

Question 8

What type of sexual selection do males favour?

Answer 8

Intra-sexual

Question 9

What does ‘inter-sexual selection’ describe?

Answer 9

This is the ‘quality over quantity’ approach and is favoured by females

Question 10

What does ‘inter-sexual selection’ describe?

Answer 10

This is the ‘quality over quantity’ approach and is favoured by females

Question 11

Why is the inter sexual selection favoured by females?

Answer 11

It is favoured by females because they invest more energy into the development of ova, which are produced in limited numbers at intervals across their lives and the fact that females experience more post coital (after sex) responsibility compared to males. Therefore a female will be more choosy as to who she mates with, due to her limited reproductive resources.

Question 12

What is an example of inter-sexual selection?

Answer 12

Fisher’s ‘sexy sons hypothesis’.

Question 13

What is the ‘Sexy sons hypothesis’?

Answer 13

It suggests that by a female choosing to mate with an attractive male, her offspring will also grow up to be attractive or ‘sexy’ , and so are themselves likely to attract females to mate with.

Question 14

What does the Sexy Sons hypothesis ensure?

Answer 14

Ensures that the female’s genes are passed on through several generations, thus increasing the likelihood that these genes will remain in the gene pool.

Question 15

What type of approach is the intra-sexual selection?

Answer 15

‘Quantity over quality’

Question 16

Why is intra-sexual selection favoured by males?

Answer 16

Because they produce sperm continuously throughout their lifetime, with little energy investment and limited post coital (after sex) responsibility. Therefore, from an evolutionary perspective, it is most effective to impregnate as many women as possible, in order to ensure the survival of their genes.

Question 17

What are some examples of intra-sexual selection?

Answer 17

• Males behaving aggressively and being protective of their female (reducing the likelihood that she will be impregnated by a competing male)
• Being larger (so more sexually desirable to women)
• Possessing certain facial and physical characteristics e,g strong jawlines and broad shoulders

Question 18

What are the limitations of current reproductive patterns?

Answer 18

Evidence suggests that it is incorrect to assume that current reproductive patterns still have a strong evolutionary basis, but rather an interactionist approach would be more accurate, where the influences of both culture and evolution are combined together.
Changing social and cultural norms means that women no longer place a large emphasis on resource-availability when looking for a new partner because women are now more financially independent, with the average age of marriage currently exceeding 30. This suggests that some evolutionary pressures for inter -sexual selection no longer apply in the modern climate.

Question 19

What are the strengths of the idea of sexual selection?

Answer 19

+ Research has suggested that there are some sexual selection pressures which have been constant in terms of evolution and in terms of modern times, such as hip to waist ratio. If this ratio is around 0.7 then this demonstrates to potential mates that the female has larger hips and a narrower waist. This suggests that some evolutionary pressures are still relevant in modern times.

+ There is evidence supporting the idea that females are more selective when it comes to potential mates due to their greater energy and genetic input into the pregnancy and care for the child. Researchers found that 75% of college males, compared to 0% of females, would be willing to sleep with a stranger if this stranger had approached them and complimented them! This supports the idea that men have an evolutionary disposition to want to impregnate as many women as possible, due to high rates of sperm roduction and little energy/ resources required to do so, and so also supports the differences in mate selections strategies used by females and males i.e intra- and inter-selection.

Question 20

Why might cultural traditions be just as important as evolutionary forces in mate preferences

Answer 20

Bernstein points out that gender differences in mate preference patterns might stem from cultural traditions rather than being the result of evolved characteristics. E.g the fact that women have been denied economic and political power in many cultures might account for their tendency to rely on the security and economic resources provided by men.

An analysis of 37 cultures showed that women valued potential mates’ access to resources far more in cultures where women’s status and educational opportunities were sharply limited.

Question 21

Why might female preferences for high status men not be universal

Answer 21

Buller claims that psychologists are mistaken in their claims of universal female preference for high status men as mates. He argues that the majority of studies attempting to determine female mate preferences have been carried out on female undergraduate students. These women expect to achieve high educational status and so have expectations of high income levels . This preference for high status men may be explained better in terms of a preference for men with similar interests, education levels and prospects of their own.

Question 22

What evidence is there that mate choice is influenced by the female menstrual cycle?

Answer 22

Research suggests that female mate choice varies across the menstrual cycle. It was found that women chose a slightly feminised version of a male face as ‘most attractive’ for a long-term relationship. However, for a short term sexual relationship, during the high conception risk phase of the menstrual cycle , the prefered face shape was more masculinised. A female might choose a main partner whose feminised appearance suggests kindness and cooperation in parental care , but might also copulate with a male with a more masculine preference when conception is most likely.