Chapter 7

Question 1

What is altruism?

Answer 1

-behavior that reduces the fitness of the individual performing the behavior ( the actor) but increases the fitness of the individual affected by the behavior ( the recipient).

Question 2

How can cooperative behaviors evolve?

Answer 2

• To answer this question theory behavioral ecologists have turned to game theory .
• Hamilton found that reciprocal altruism can evolve and persist in a population where individuals adopt a behavioral strategy called tit for tat. -In this strategy, an individual treats another individual the same way it was treated the last time they met.
• Individuals are always altruistic, or cooperative, on the Frst encounter, and will remain so as long as their altruism is reciprocated.
• When it is not, they will retaliate immediately but will return to cooperative behavior as soon as the other individual becomes cooperative.
• ANIMALS LEARN BY OBSERVING OTHERS
• Social learning is learning through observing others.
• Social learning forms the roots of culture, which can be defined as a system of information transfer through social learning or teaching .
• Cultural transfer of information has the potential to alter behavioral phenotypes and inFuence the fitness of individuals.

Question 3

Why do related individuals cooperate more than unrelated ones?
-Know how primates identify maternal and paternal kin

Answer 3

-related individuals cooperate more than unrelated one due to kin recognition.
Altruism can evolve between closely related individuals as a result of kin selection.
Primates know who their relatives are due to:
1)Contextual cues- infants in contact with mother
- siblings connected through mother
Maternal siblings ( siblings on their mothers side)
2)Phenotypic matching:
- Recognize kin through smell or likeliness to themselves
-Could explain how paternal kin recognize one another as relatives
3) Same aged monkeys [same peer group) tend to interact more often than monkeys that are non peers.
4) Peers likely to be kin in multi male or one male meeting systems.
-Conceived during the reign of a single dominant male.
5) Paternal siblings interact more often than non kin , even in same peer groups

Question 4

What cooperative acts do we see in primates?

Answer 4

-Evidence for cooperative behavior among kin
Grooming
Coalition
Cooperative breeding

Question 5

Under what circumstances do unrelated individuals cooperate with one another?

Answer 5

-under reciprocal altruism 
Individuals balance reciprocal acts outside of kinship networks 
Many different currencies 
Grooming
Food sharing 
Coalitionary support

Reciprocal altruism criteria:
Frequent interactions
Ability to keep track of actions given and received
Support those who support you

Question 6

Altruism v. Mutualism

Answer 6

Altruism –behavior that reduces the fitness of the individual performing the behavior ( the actor) but increases the fitness of the individual affected by the behavior ( the recipient).

Mutualism-Interaction between two organisms where each gains a fitness benefit

There is no overall cost to the actor in helping
Vulnerable to cheaters – if individuals can reap rewards without the cost, then mutualistic behavior do not persist
Ex. bees pollinating flowers

Question 7

Kin selection

Answer 7

-Each individual shares genetic material with their relative

Even if an individual never reproduces, it is possible to have some of their genes represented in the next generation if their relatives are reproductively successful

• Natural selection operates on genes rather than individuals
• Inclusive fitness

A theory by W.D .Hamilton (1964)stating that altruistic acts will be favored if the product of the benefit to the recipient and the degree of relatedness (r) between the actor and recipient exceeds the cost to the actor.

Relatives of an individual, which share many of the same genes, have an increased fitness.
Increased fitness = inclusive fitness.

Question 8

Hamilton’s rule

Answer 8

-An individual will be selected to help a relative whenever c < b x r

Individuals are most likely to help close kin as the costs increase

A rule predicting that altruistic behavior among relatives will be favored by natural selection if rb> c,
where r is the coefficient of relatedness between actor and recipient,
b is the sum of the benefits of performing the behavior on the fitness of the recipients, and
c is the cost, in decreased fitness of the donor, of performing the behavior.

Question 9

Chimera

Answer 9

-a combination of more than one genetic lineage within a single individual.

Question 10

Parent-offspring conflict

Answer 10

-conflict that arises between parents and offspring over how much the parents will invest in the offspring. These conflicts stem from the opposing genetic interests of parents and offspring.

Question 11

Reciprocal altruism

Answer 11

-a theory that altruism can evolve if pairs of individuals take turns giving and receiving altruism over the course of many encounters.
I’ll scratch your back if you scratch mine.

Question 12

Grooming : costs and benefits

Answer 12

Hygiene
Reinforce social relationships
Conflict resolutions

Grooming costs:
Time and energy

Question 13

Grooming: kin

Answer 13

Mostly between mother and infants

Occurs more often between kin than distant kin or non kin

Question 14

Coalition / alliances

Answer 14

Form during disputes involving 2 or more individuals.
Qualify as altruism- may result in victory in dominance contest or risk of injury.
See it more often between kin and non kin.
By helping their fathers Menting dominance, they are indirectly improving their own reproductive success
Inclusive fitness

Question 15

Matrilineage hierarchies

Answer 15

All females in a higher rank lineage can defeat all the other members of a lower ranking lineage.

Question 16

Cooperative breeding

Answer 16

A single breeding pair 
Other members of the group help raise the offspring 
Carrying them
Feeding them
Protecting them from predators

Question 17

Despite observations, most researchers still agree that

Answer 17

Kin selection plays a more important role then reciprocal altruism

Question 18

Parent offspring conflict

Answer 18

Not everyone is equally related and therefore may have different agendas and motivations .
parents often more closely related to offspring than offsprings are to each other.
Fitness of future offspring comes at the expense of current offspring. Benefits mother.
Does not benefit the current offspring.
Manifest itself in primates in the form of tantrums and sibling rivalries.

Question 19

Kin biases in behavior

Answer 19

As a result of kin selection, related primates display more altruistic behavior and cooperate more with related individuals that but unrelated individuals

Question 20

Altruism can evolve through———.

Answer 20

Kin selection

Question 21

Natural selection operates on the level of the

Answer 21

Individual, not the group

Question 22

Evolution operates on the level of the

Answer 22

Population, not the individual

Question 23

Altruism

Answer 23

Must ultimately favor the individual, not the groups to evolve .
Group level explanations do not fit our understanding of evolutionary theory

Question 24

Primates have evolved many adaptations to

Answer 24

Maximize their survival and reproductive output.