PBSI 311 EXAM 2 QUESTIONS WITH
100% CORRECT ANSWERS | LATEST
VERSION 2025/2026.
What are the 4 paths to cooperation - ANS 1) Kin selection
2) Reciprocity
3) Byproduct mutualism
4) Group selection (controversial, will not be covered)
cooperation - ANS The outcome of 2 or more individuals interaction is that they receive a net
benefit from their interactions even though there are costs
Cooperation in Elephants - ANS Tasks:
1. Elephants trained to pull a rope attached to a table to get a bowl of food (solo task)
2. Elephants needed to work together to pull 2 ropes to get a food reward
3. Elephants released at the same time but one rope is made inaccessible (working together not
possible, no cooperation)
cooperation in Rodrigues fruit bats - ANS Behaviors:
Demonstrated birthing posture (feet down)
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,Groomed mother during birthing
Licked newborn
Assisted with positioning pup for nursing
Why:
Assistance may be related to bonds built through roosting proximity
cooperation in primates (benefits of social grooming) - ANS Health benefit:
- removal of parasites
Social benefit:
- Tension reduction (hormone levels are affected such that aggression is reduced)
- Resource that can be exchanged for food, assistance with an aggressor/predator
What is reciprocity or reciprocal altruism? - ANS exchanging acts of cooperative and altruistic
behavior
Key features:
- Individual cooperates in the first encounter with a partner
- Then copy the partner's response (cooperate vs.'cheating'/not cooperate)
- 'Forgives' cheating if the partner is currently cooperating
cooperating and 'cheating' - ANS Cooperating = inspecting together
'Cheating'/not cooperating = lagging behind or not inspecting
How are risk-taking tendency and survival correlated? (predator inspection in guppies) -
ANS Survival was highest for low inspectors
minnows transmitter study - ANS Inspectors (transmitters)
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, decrease feeding as they approach predator
Non-inspectors (receivers)
respond to inspector behavior and also decrease feeding
guppies able to recognize risks, 3 key findings? - ANS 1. Fewer inspections of predator head
2. Inspector group size smallest when inspecting predator head
3. Approach distance was farthest away for predator head
food sharing in vampire bats & reciprocity - ANS Reciprocity increases chances of food
sharing
Hungry bat will be more likely to get a shared meal if she has fed the satiated bat sometime in
the past
being related increases the likelihood of food sharing.
byproduct mutualism? - ANS Definition: Cooperation is a 'byproduct' of a situation in which
an individual would suffer a cost by not cooperating
byproduct mutualism animal examples - ANS 1) Female yuhina jays & harsh environments
2) House sparrows & large food source
How does byproduct mutualism differ from reciprocity? - ANS Differs from reciprocity:
1) No temptation to 'cheat' or not cooperate
2) Past behavior is not relevant (no scorekeeping) because cooperating is in the best interest of
all parties
What is a coalition? - ANS Two or more individuals that cooperate to act against another
individual or group
3 | Page @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
100% CORRECT ANSWERS | LATEST
VERSION 2025/2026.
What are the 4 paths to cooperation - ANS 1) Kin selection
2) Reciprocity
3) Byproduct mutualism
4) Group selection (controversial, will not be covered)
cooperation - ANS The outcome of 2 or more individuals interaction is that they receive a net
benefit from their interactions even though there are costs
Cooperation in Elephants - ANS Tasks:
1. Elephants trained to pull a rope attached to a table to get a bowl of food (solo task)
2. Elephants needed to work together to pull 2 ropes to get a food reward
3. Elephants released at the same time but one rope is made inaccessible (working together not
possible, no cooperation)
cooperation in Rodrigues fruit bats - ANS Behaviors:
Demonstrated birthing posture (feet down)
1 | Page @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,Groomed mother during birthing
Licked newborn
Assisted with positioning pup for nursing
Why:
Assistance may be related to bonds built through roosting proximity
cooperation in primates (benefits of social grooming) - ANS Health benefit:
- removal of parasites
Social benefit:
- Tension reduction (hormone levels are affected such that aggression is reduced)
- Resource that can be exchanged for food, assistance with an aggressor/predator
What is reciprocity or reciprocal altruism? - ANS exchanging acts of cooperative and altruistic
behavior
Key features:
- Individual cooperates in the first encounter with a partner
- Then copy the partner's response (cooperate vs.'cheating'/not cooperate)
- 'Forgives' cheating if the partner is currently cooperating
cooperating and 'cheating' - ANS Cooperating = inspecting together
'Cheating'/not cooperating = lagging behind or not inspecting
How are risk-taking tendency and survival correlated? (predator inspection in guppies) -
ANS Survival was highest for low inspectors
minnows transmitter study - ANS Inspectors (transmitters)
2 | Page @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, decrease feeding as they approach predator
Non-inspectors (receivers)
respond to inspector behavior and also decrease feeding
guppies able to recognize risks, 3 key findings? - ANS 1. Fewer inspections of predator head
2. Inspector group size smallest when inspecting predator head
3. Approach distance was farthest away for predator head
food sharing in vampire bats & reciprocity - ANS Reciprocity increases chances of food
sharing
Hungry bat will be more likely to get a shared meal if she has fed the satiated bat sometime in
the past
being related increases the likelihood of food sharing.
byproduct mutualism? - ANS Definition: Cooperation is a 'byproduct' of a situation in which
an individual would suffer a cost by not cooperating
byproduct mutualism animal examples - ANS 1) Female yuhina jays & harsh environments
2) House sparrows & large food source
How does byproduct mutualism differ from reciprocity? - ANS Differs from reciprocity:
1) No temptation to 'cheat' or not cooperate
2) Past behavior is not relevant (no scorekeeping) because cooperating is in the best interest of
all parties
What is a coalition? - ANS Two or more individuals that cooperate to act against another
individual or group
3 | Page @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
