Evolutionary Explanations - Anisogamy

Question 1

What is the part of sexual selection that anisogamy is responsible for?

Answer 1

Men and women not wanting the same thing.

Question 2

What is anisogamy?

Answer 2

The differences between the number of sperm and eggs produced.

Question 3

What does anisogamy cause?

Answer 3

Differences in sexual selection strategies between males and females.

Question 4

What is the difference between males and females in terms of the number of sperm and eggs they have?

Answer 4

Sperm - Many.

Eggs - Relatively few.

Question 5

What is the difference between males and females in terms of the energetic cost of having sperms or eggs?

Answer 5

Males - Energetically cheap.

Females - Energetically expensive.

Question 6

What does natural selection favour men doing?

Answer 6

Maximising the number of potential pregnancies by having sex with as many females as possible.

Question 7

Why does natural selection favour men maximising the number of potential pregnancies?

Answer 7

Because they cannot be sure of paternity.

To have a better chance at one good baby.

Question 8

What does anisogamy give rise to in terms of partner preference?

Answer 8

Two different mating strategies.

Question 9

What are the two different mating strategies that are given rise to by anisogamy?

Answer 9

Intrasexual selection.

Intersexual selection.

Question 10

Is intrasexual selection a preferred strategy for men or women?

Answer 10

Men.

Question 11

What is intrasexual selection (using men to describe)?

Answer 11

When males compete with other males to get access to better females.

Question 12

How do traits get passed on with intrasexual selection?

Answer 12

The traits that lead to successful mating in these contests get passed on.

Question 13

In intrasexual selection, what is one thing that will make a female ‘better’?

Answer 13

Youthfulness, they seem more fertile.

Question 14

Is intersexual selection a preferred strategy for men or women?

Answer 14

Women.

Question 15

What is intersexual selection?

Answer 15

The preference for certain traits in the opposite sex,

Question 16

What causes the preferences for certain traits within intersexual selection?

Answer 16

Indications that they have ‘good genes’ meaning they would produce successful offspring and have the ability to support and protect the offspring.

Question 17

Under which sexual selection does the ‘sexy sons hypothesis’ come?

Answer 17

Intersexual selection.

Question 18

What does the sexy sons hypothesis claim?

Answer 18

Women do not sleep with attractive men because they find them attractive, its because they want attractive children, then others will find these children attractive in the future.

Question 19

What is a slightly more technical explanation of the sexy sons hypothesis?

Answer 19

A female mates with a male who has a desirable characteristic, this ‘sexy’ trait is passed onto her son, this increases the likelihood that successful generations of females will mate with her offspring.

Question 20

When choosing a long term partner, who will females be attracted to?

Answer 20

A male who will stick around, look after her and be attractive.

Question 21

Why are women seeking long term partners that will stick around and be attractive?

Answer 21

Because of the output of parental investment (the cost of having a child and pregnancy).

Question 22

When choosing a long term partner, who will males be attracted to?

Answer 22

Demonstrate fertility/

Question 23

Why are men seeking long term partners that demonstrate fertility?

Answer 23

If a man is going to be stuck with one women (which they don’t want anyway) then it needs to be someone fertile so they can still have the chance to have lots of children.