Relationships: sexual selection

Question 1

Define sexual selection

Answer 1

Attributes or behaviours that increase reproductive success are passed on and may become exaggerated over succeding generations or offspring.

Question 2

What is Anisogamy?

Answer 2

The basis for human reproductive behaviour is ansigomy
Differences between male and female sex cells
* Sperm vs Egg
* Large vs Small
* Quantity
* Energy vs expenditure
* Rare vs common
These differences lead to specific mating strategies.

Question 3

What is the consequences of the differences in sexual selection?

Answer 3

These differences in mating strategies lead to different partner preferences in males and females.

Female
* Genetically fit partners with “resources”
* Intelligence, creativity, status, ambition, financial prospects.

Males
* Fertility
* Youth
* Chastity
* Physical signs that production of a healthy offspring is achievable.

Question 4

What is a strength of research into sexual seletion?

Answer 4

Research Support: Female choosiness
Female choosiness was illustrated by the study conducted by Clark and Hatfield (1989)

• They asked male and female student volunteers to approach opposite sex students individually on a univeristy campus, asking the same question: ‘ Ive noticed you around the campus. I find you very attractive. Will you go to bed with me tonight’
• They found gender differences in the responses : 75% males agreed whereas not a single female said ‘yes’

This supports evolutionary theory because it suggests that females are choosier than males when it comes to selecting sexual partners and that males have evolved a different strategy to ensure reproductive success

Question 5

What is a weakness of the sexual selection theory?

Answer 5

Research Critique: More complex
mate choice may be more complicated than suggested by this approach

Research by Penton-Voak et al (1999) suggests that female mate prefrences change across the menstrual cycle

• They found that females preferred a partner with strong masculine features during their most fertile period whereas they showed prefernece for a partner with slightly feminised features as a long term mate.
• masculine appearance preferred - healthier immune system, advantageous and could pass to offspring
• feminine features - suggest kindess and parental cooperation - very desirable traits in a long term partner!

These findings suggest that mate choice may actually be based on a range of factors; rather than simply indicators of gentic fitness

Question 6

What is a strength of the theory of sexual selection?

Answer 6

Reserach support: Prefrences based on Anisgomy
Partner prefernce was supported by research conducted byBuss(1989)

• He conducted surveys in over 33 countries and 10,000 adults and asked questions relating to ages and attributes that evolutionary theory predicts should be important for partner prefrence
• He found that women placed a greater value on resource related characteristics such as good finacial prospects, ambition and industriouness than men did.
• Whereas males valued reproductive capacity in terms of good looks, chastity and preferred younger mates.

These findings reflect sex differences in mate strategies due to anisgomy. They support predictions about partner prefence derived from sexual selection theory. Futhermore, the findings can be applied across a vastity of different cultures, relfecting fundamental human prefernces which are not primarily dependant on cultural influences.

Question 7

What is a weakness of the sexual selection theory?

Answer 7

Weakness : Social and Cultural Influences Underestimated
One limitation of sexual selection theory is that evolutionary theories overlook the influences of social and cultural factors on partner preference.

• Partner preference over the past century have been undoubtedly been influenced by rapidly changing social norms of behaviour. These develop much faster than evolutionary timescales imply and have instead come about due to cultural factors (eg. the introduction of contraception)
• Furthermore womens greater involvement in the workplace means they are no longer dependent on men to provide for them (despite the ongoing inequality in earning). Bereczkei et al (1997) argues that this social change has consequences for women’s mate preference, which may no longer be resource-oriented.

Therefore, partner preference is more likely to be the outcome of a combination of evolutionary and cultural influences, and any theory that fails to account for both is limited

Question 8

What is a weakness of the sexual selection theory?

Answer 8

Weakness: Sexual Selection and Homosexuality

• A criticism often made of sexual selection theory is that it cannot explain partner preferences of gay men and lesbian women. This mainly because in homosexual relationship partners are not assessing genetic fitness.
• To investigate this, Lawson et al. (2014) looked at personal ads placed by heterosexual and homosexual men and women and found the prefererences of homosexual men and women differ just as they do in heterosexual men and women

This similarity in selection strategies may exist because all people, whether homosexual or heterosexual, assess genetically-related qualities that are relevant to raising offspring (e.g. kindness, protectiveness, etc.)