Chapter 9 book (exam3) - Ellen

Question 1

Sexual Selection Theory

Answer 1

Form a natural selection that acts on traits used to compete for mates with others of the same sex or to attract members of the opposite sex in order to mate with them

Question 2

Ornaments

Answer 2

An elaborate morphological trait that has apparently been selected for because it attracts mates

Question 3

Armaments

Answer 3

Elaborate morphological traits that have been selected for because they act as weapons in intrasexual battles
ex: Horns, tails, tusks, antlers, etc.

Question 4

Reproductive Skew

Answer 4

unequal partitioning of reproduction within a population or social group (some males get many mates while others only get a few).

Question 5

Fundamental Asymmetry of Sex

Answer 5

Males produce small sperm (and many) while Females produce large eggs (relatively few) based on premise that sperm are energetically “cheaper” to produce than eggs

Question 6

Anisogamy

Answer 6

Fusion of gametes (sperm and egg) that differ so greatly in size

• Bird egg may constitute 20% of females body mass
• Male reproductive success increases with number of mates

Question 7

Bateman’s Principle

Answer 7

Because males achieve greater reproductive success, they tend to have more mates than females do. As a result, they tend to have greater reproductive variance than females do.

Question 8

Parental Investment

Answer 8

Costly parental activities that increase the likelihood of survival for some existing offspring but may reduce the parents’ chance of producing offspring in the future
- Females are more likely to derive a net benefit from parental investment

Question 9

Operational Sex Ratio

Answer 9

Ratio os sexually active males to sexually receptive females in a population

Question 10

Sex Role Reversal

Answer 10

A change in typical role patterns of males and females, as when, for example, females compete for males or when males choose selectively for potential mates

Question 11

Nuptial Gift

Answer 11

food item transferred from male to female just prior to or during copulation
- When sexual selection operates strongly in both sexes, end result could be mutual ornamentation and mate choice

Question 12

Intrasexual Selection

Answer 12

Sexual selection where members of the same sex compete for access to mates

Question 13

Intersexual Selection

Answer 13

Sexual selection usually involving male courtship behavior or appearance that influences female’s selection of mate

Question 14

Sexual dimorphism

Answer 14

Difference in appearance between males and females in the same species

Question 15

Dominance Hierarchy

Answer 15

Social Ranking within group. Some individuals give way to others often conceding useful resources without a fight

• Dominante males (mammals) often mate more than subordinate
• Lower-ranking males can and do develop friendship with females. Once male demonstrates that he can and will protect female and infant, she may seek him out when she enters estrus again
• Males can also bond in groups and challenge the lone dominant when it comes to females
• these friendships are called alternate mating tactics - a kind of behavioral polyphenism

Question 16

Conditional Mating Tactics

Answer 16

Genetically based capacity of an individual to use different mating tactics under different environmental conditions

• Bigger weapons on males (like horns) the smaller the testes
• Difference between behavioral phenotypes: Environmentally caused

Question 17

Alternative Mating Strategy

Answer 17

Behavioral polymorphism in which a mating behavior has a strong genetic component is therefore inflexible and fixed throughout the component’s life

Question 18

Sperm Competition

Answer 18

Competition among the sperm of different males that determines who’s gametes will fertilize a female’s eggs
- Sperm can discriminate between genetically related and unrealted sperm

Question 19

Aggregations

Answer 19

Traits of 100s - 1’000s of cells that increase sperm mobility and allow it to reach the egg quicker