Chapter 11 Part 1

Question 1

What is the key to explaining diversity in parental behavior across species?

Answer 1

cost-benefit approach

Question 2

time and energy invested in offspring

Answer 2

parental investment

Question 3

reproductive value

Answer 3

a measure of the potential of an individual to leave surviving descendants in the future

Depends on ecological or social circumstances an individual is born into, a value which influences amount of care provided by parents

Question 4

Variations in offspring care may be due to:

Answer 4

behavior (advertising need or quality), behavior of parents, and parent-offspring conflict

Question 5

signal of need hypothesis

Answer 5

signals that advertise an offspring’s level of need in order to maximize their chance of being fed by their parents

Question 6

signal of quality hypothesis

Answer 6

signals that advertise an offspring’s quality or merit in order to maximize their chance of being fed by their parents

Ex. the bright red mouths of songbirds; obtained through carotenoids in the diet and an indication of immune functioning and health

Question 7

Barn swallow research

Answer 7

offers support for the signal of quality hypothesis

offspring with artificially enhanced red mouths given preferential treatment; offspring made ill given less parental care

Question 8

Whether a species uses a signal of need or signal of quality to determine allocations of parental care depends on:

Answer 8

the different ecological conditions experienced by parents while raising young

Question 9

In instances with food and resource abundance, parents will preferentially feed the (neediest/highest quality) offspring; in instances with food and resource shortages, parents will preferentially feed the (neediest/highest quality) offspring

Answer 9

1. neediest

2. highest quality

Question 10

Altricial

Answer 10

referring to young that reside in the nest for an extended period of time

ex. swallows

Question 11

precocial

Answer 11

referring to young that are mobile soon after hatching

ex. coots; exceptionally needy chicks are refused resources and pecked to death by their parents

Question 12

Red mason bee parental favoritism

Answer 12

when females are young and robust will give more food to offspring and produce daughters (fertilized, bigger); when females begin to deteriorate they provide less and produce males (unfertilized, smaller)

Question 13

Ronald Fisher & Fisherian ratio of males to females among a population

Answer 13

1:1

over time the population would equilibrate; assumes males and females are equally costly to make

Question 14

local competition hypothesis

Answer 14

when related individuals compete for resources or mates, then one sex is more costly to produce; sex ratio would be skewed in favor of a single sex (if one sex of potential offspring will compete with a parent for resources –> beneficial to have offspring that will disperse)

Question 15

local enhancement hypothesis

Answer 15

when one sex provides resources or enhances the mating success of its relatives, then that sex is cheaper to produce (if one sex of potential offspring will help a parent –> more of that sex)

Question 16

Seychelles warbler

Answer 16

if food was scarce would produce more sons that disperse; if food was plentiful would produce more daughters that stayed and helped

Question 17

Trivers-Willard hypothesis

Answer 17

mothers can adjust offspring sex ratio according to their own body condition (itself related to territory quality and resource availability)

Question 18

Parental Favoritism in humans

Answer 18

the potential to be polygamous gives sons a higher reproductive value than daughters in certain conditions; they will also have higher reproductive value if they are developmentally advantaged and can compete with rival males

Question 19

Examples of parental favoritism in humans

Answer 19

Rwanda - high-ranking mothers have more sons than do low-ranking mothers

Inheritance rules in relation to polygamy; sons more likely to receive greater portion of inheritance than daughters

Mukogodo tribe of Kenya - participate in livestock pastoralism but arrived at that type of livelihood far after their neighbors and thus are considered ‘poor’ and sons are unable to obtain many wives because they are unable to provide the dowry necessary; women however have greater reproductive success because they are all likely to marry - as infants mothers are more likely to nurse daughters longer and take then to get medical care sooner than sons

Question 20

sibling conflict

Answer 20

evolutionary conflict resulting from divergent interests among current and/or future siblings

ex. great egrets

Question 21

siblicidal behavior

Answer 21

behavior that results in an individual killing a sibling or siblings

Question 22

parent-offspring conflict

Answer 22

evolutionary conflict arising from differences in optimal parental investment in an offspring from the standpoint of the parent versus that of the offspring

ex. blue footed boobies that resist siblicidal behaviors

Question 23

obligate siblicide

Answer 23

behavior that always results in an individual killing a sibling or siblings

Question 24

facultative siblicide

Answer 24

behavior that occasionally results in an individual killing a sibling or siblings

Question 25

reproductive insurance hypothesis

Answer 25

mothers in siblicidal species lay a second egg as insurance against hatching failure

Question 26

facultative siblicide hypothesis

Answer 26

parents permit siblicidal behavior only when resource availability is low

Question 27

Ghalambor and Martin predict this regarding costs of parental care:

Answer 27

two key factors:
1) nature of the predator 2) annual mortality rate for breeding adults

(if a parent is likely to survive to produce more, will provide less parental care/risk; if a parent is likely to die, will invest a great amount of care/risk)