Chapter 22

Question 1

Explain the difference between natural selection and sexual selection

Answer 1

Natural selection focusses on fitness for survival and reproduction and sexual selection focusses on mates selecting for the best genes/traits

Question 2

Name 3 asymmetries of sexual reproduction

Answer 2

Number of gametes, parental investment, number of mates available

Question 3

Describe the number of gametes asymmetry

Answer 3

Males can have many babies; females can only have a certain amount

Question 4

Describe what limiting fertility leads to

Answer 4

Selective pressure for males to compete to gain access to mating and selective pressure for females to be able to choose their mate

Question 5

How do males maximize their reproductive success?

Answer 5

Through competing for more mates

Question 6

How do females maximize their reproductive success?

Answer 6

Through choosing their mate really well; often based on traits that lead to good genes

Question 7

Intersexual Selection

Answer 7

Genetically determined behaviors; preferences for certain characteristics are genetic

Question 8

Models of Intersexual Selection

Answer 8

Direct Benefit, Good Genes, Runaway Sexual Selection, Sensory Bias

Question 9

Direct Benefit

Answer 9

Mate who gives a direct benefit; often chosen based on the best gift

Question 10

Good Genes

Answer 10

Selection may factor females that select for good genes in male

Question 11

How can you determine a mate has good genes?

Answer 11

Honest indicators such as antlers, colors, songs/dances

Question 12

What are honest gene indicators in humans?

Answer 12

Symmetry in face, signs of testosterone; deep voice, cut face, v-shape body, signs of estrogen; curves, indicators of youth

Question 13

Runaway Sexual Selection

Answer 13

Genetic correlation between trait in male and actual preference of female

Question 14

What is an example of runaway sexual selection?

Answer 14

Selection for red causes more preference for red and a more exaggerated trait in males

Question 15

Sensory Bias

Answer 15

Preference a female has i not based on anything; can be seen in phylogenetic tree; preference preexists the actual evolving trait

Question 16

Intrasexual Selection

Answer 16

Male-Male competition

Question 17

Cuckoldry

Answer 17

Tricking other males in competition

Question 18

Postcopulatory Sexual Selection

Answer 18

Sperm Competition; differences change the amount of sperm

Question 19

Sexual Conflict

Answer 19

Trait that maximizes sexual reproductive success in males can have a detrimental effect on females

Question 20

Two examples of sexual conflict

Answer 20

Ducks; opposing genitalia

Bed bugs: Traumatic insemination, males bypass genitalia

Question 21

Handicap Hypothesis

Answer 21

Good genes hypothesis