lecture 19

Question 1

Distribution of males and females when food is sparse, patchy, and slowly renewed

Answer 1

territorial females that are uniformly distributed, non-territorial males

Question 2

Distribution of males and females when food is abundant, evenly distributed, rapidly renewed

Answer 2

non-territorial females, territorial males

Question 3

When females are asynchronous and clumped or dispersed in space

Answer 3

males are non-territorial and promiscuous

Question 4

when females are synchronous and clumped in space

Answer 4

males are territorial and polygamous

Question 5

when females are synchronous and dispersed

Answer 5

males are territorial and monogamous

Question 6

Study: How much to invest in offspring based on lifespan

Answer 6

If you have a shorter lifespan, you should invest more in your current offspring; Starlings have short lifespan and invest more; storm petrel have longer life and invest less

Question 7

3 factors to determine how much care to give current brood

Answer 7

Brood size, genetic relatedness, future mating opportunities

Question 8

Sunfish example: effect of brood size on parental care

Answer 8

If brood size (# of eggs guarded) is experimentally reduced, defense of brood is reduced accordingly; smaller the brood, the less males defend it

Question 9

Bluegill sunfish: importance of genetic relatedness

Answer 9

males defend offspring based on degree of parental certainty; in the experimental condition where additional males were placed in the tank, male defended eggs less than when male was only male in tank; however, defend fry more than eggs even when there is another male around because he can tell whether the hatched fry are related to him

Question 10

Rainbow cichlids: importance of future mating opportunities

Answer 10

the more female-biased the population, the more likely that the male will abandon the brood

Question 11

Bluethroat birds: effect of sibling size on allocated resources

Answer 11

when offspring differed in size, parents invested more (provided more food) in larger sibling, because larger offspring would have greater chance of being reproductively successful in future

Question 12

Spotted hyenas- sibling rivalry

Answer 12

when alpha female has female offspring, they fight for dominance as soon as they are born over who will become the direct subordinate to mom (beta); the weaker female sibling often dies from lack of nursing since more dominant sister takes all the resources

Question 13

Why would parents condone siblicide?

Answer 13

efficient brood reduction when food is scarce since only strongest sibling survives; maybe you produce too many offspring just in case due to high prevalence of disease

Question 14

2 primary questions of parental care

Answer 14

1. Who cares?

2. How much care?

Question 15

Mode of fertilization and role on who provides care

Answer 15

Internal fertilization: female parental care; external fertilization: male parental care (male wants to guard his fertilized eggs)

Question 16

Back brooding

Answer 16

males take care of the young; females produce the eggs and then males guard them

Question 17

Hamilton’s Inequality (Kin selection)

Answer 17

rB>C

r: coefficient of relatedness; B: benefit to recipient for help provided; C: cost to self for providing help

Question 18

Parent-offspring conflict curve

Answer 18

Looks at time of dependency of offspring on parent vs the B/C ratio for parent; predicts that the parent prefers an earlier end to dependency and offspring prefers a later end, resulting in some conflict over when the parent will stop providing resources

Question 19

Costs vs benefits of parental help

Answer 19

Benefit= benefit to current offspring; cost= reduction in future offspring

Question 20

Weaning

Answer 20

period of conflict during which the offspring tries to acquire resources and parent attempts to withhold them; this conflict ends when both parents and offspring agree that future investment of parent is better directed at future rather than current offspring