Sexual Selection

Question 1

What is sexual selection?

Answer 1

An evolutionary explanation of partner preference.

Question 2

How does sexual selection lead to survival of organisms that may not be the ‘fittest’?

Answer 2

Their reproductive characteristics may be beneficial.

Question 3

Give an example of a sign of genetic fitness seen in male peacocks that possess no survival advantage.

Answer 3

Brightly coloured feathers which attract females.

Question 4

What is anisogamy?

Answer 4

Differences between male and female gametes.

Question 5

Describe the size, movement, volume and ages that male gametes are produced.

Answer 5

Very small, mobile, produced in high volume from puberty until death.

Question 6

Describe the size, movement, volume and ages that female gametes are produced.

Answer 6

Large, static, low in volume, produced periodically from puberty and released once a month.

Question 7

Why is there no shortage of fertile males but a shortage of fertile females?

Answer 7

Males produce gametes almost all of their lives but females only produce gametes for a limited number of years.

Question 8

What is intersexual selection?

Answer 8

The strategies used by males or females to select a member of the opposite sex to mate with.

Question 9

Why do females need to be more ‘choosy’ and select the best male?

Answer 9

The consequences of mating are much greater for the female as they involve more time, money etc

Question 10

How does inter sexual selection allow females to determine the characteristics her offspring will receive?

Answer 10

Females can choose males with the best characteristics, such as height, to ensure her offspring will have these characteristics.

Question 11

What is Fisher’s ‘sexy sons hypothesis’?

Answer 11

A theory that states that females mate with the most attractive males possible so their son’s will inherit these traits. This allows the son to successfully mate with other females when he is older.

Question 12

Which sex favours inter sexual selection?

Answer 12

Females

Question 13

What is intra sexual selection?

Answer 13

Competition between one sex for the opposite sex.

Question 14

Which sex favours intra sexual selection?

Answer 14

Males

Question 15

Why do males use intra sexual selection?

Answer 15

To compete with other males and mate with the female.

Question 16

What is dimorphism?

Answer 16

Where males and females look different to eachother.

Question 16

How are males rewarded after competing and mating with a female?

Answer 16

The offspring produced will contain the characteristics that contributed to him successfully getting the female.

Question 17

Why are males strong and aggressive?
Give 2 reasons.

Answer 17

Enables them to compete with eachother.
Also allows them to protect females from other males.

Question 18

Why do females typically appear youthful?

Answer 18

Indicates fertility.

Question 19

Explain the strength of there being research support for inter sexual selection.
Use the example of Clark and Hatfield’s study of how many male and female university students agreed to sleep with a person they just met.

Answer 19

Clark and Hatfield sent male and female psychology students out across a university campus. They approached other students individually and asked them ‘I have been noticing you around campus. I find you very attractive, would you go to bed with me tonight?’. 75% of males agreed where 0% of females agreed. This supports that females are choosier than males when it comes to selecting mates. This also suggests men have a different strategy when it comes to choosing a female (quantity over quality).

Question 20

Explain the strength that there is research support from animals from sexual selection.
Use the example of birds and the strategies males and females use to select a mate.

Answer 20

Research has found that females are more likely to choose a male to mate with, whereas males are more likely to compete with other males for a female. For example, this is seen in male birds, who are brightly coloured to draw the female’s attention. The females then select the male with the ‘sexiest’ characteristics. Female birds are usually brown, telling us that they do not need to be chosen. Additionally, some male birds also clean where they live before attracting a female. This shows the female that they have a good place for the offspring to be raised, therefore allowing the female to choose the best male, supporting theory of inter sexual selection.

Question 21

Explain the strength of there being research support for intra sexual selection.
How many adults did Buss survey? How many different countries were these adults from?
What were the questions on his survey generally about?
Females place greater value on which type of characteristics?
What characteristics do males value more?
What do these findings support?

Answer 21

Buss carried out a survey of over 10000 adults in 33 different countries. He asked questions relating to a variety of attributes that evolutionary theory predicts are important. He found that females placed greater value on resource related characteristics such as good financial prospects and ambition. Males also valued physical attractiveness and signs of fertility more than females. These findings reflect consistent differences between partner preferences of the two sexes, supporting predictions from sexual selection.

Question 22

Explain the limitation of sexual selection exaggerating differences between males and females.
Buss found that both men and women thought physical attractiveness and signs of genetic fitness were as equally valuable as what other factors?
These findings might be a result of changes in s______ n_____. Why do women do not need to depend on men as much anymore?

Answer 22

The different factors prioritized by men and women in prospective partners are over emphasised and similar qualities that both genders prefer are under emphasised. For example, buss reported that men prefer younger women with a low waist to hip ratio because it’s a sign of fertility and childbearing potential. However, he overlooked important findings; in one of his studies, ‘kind’ and ‘intelligent’ were universally ranked as more important than ‘attractive’ or ‘good earning power’ by both men and women. This may be due to the influence of changing social norms. Women have a greater role in the workplace and no longer depend on men to provide for them.