Parental Investment

Question 1

What are the 4 types of parental care

Answer 1

1. no parental care
2. maternal care
3. paternal care
4. biparental care

Question 2

What are the 3 causes of early mortality

Answer 2

1. predation - separated from mother or lack of care
2. food stress
3. infanticide

Question 3

Why is the sex of an infant important

Answer 3

1. biology - males are the fragile and costly sex

2. culture - certain sex may be more important and valued more

Question 4

2 examples of sex ratio and birth timing

Answer 4

1. high quality red deer hinds give birth to sons early in the season. low quality give birth to daughters late in the season
2. high status macaques give birth to daughters early in the season

Question 5

Factors for post natal investment

Answer 5

1. males more likely to die and are more costly

2. delay before next conception. longer delay after daughters in macaques

Question 6

factors for infanticide in humans

Answer 6

1. uncertainty surrounding paternity - only invest if there is a high certainty. males demand assurances e.g virgin brides and making dress conservative, chaperones
2. low quality infant - severe physical deformities, low evolutionary pay off e.g unlikely to reproduce
3. lack of parental resources - have to raise in a poor environment. conserve resources and invest when conditions improve

Question 7

2 examples of grandmothers helping

Answer 7

1. elephants - infants more likely to survive when grandmother helps raise
2. humans - grandmothers help with income

Question 8

What is parental investment

Answer 8

Care or effort invested in current offspring that reduces the capacity to invest in future offspring

Question 9

What is parental effort

Answer 9

Measure of the effort required to care for offspring

Question 10

What is parental care

Answer 10

Behaviour by 1 or both parents that contribute to the survival of offspring

Question 11

What is the sex ratio bias

Answer 11

If 1 sex has greater variance in reproductive success

And

Mothers vary in physical condition

Then

There are differences in preference in sex of offspring