FUCKING FINAL

Question 1

How does sociality evolve?

Answer 1

Sociality only evolves if it results in an individual in a group obtaining higher fitness than it would living alone

AKA Net Benefits > Net Costs

Question 2

What re the Benefits of Sociality

Answer 2

1) Increased diet breadth for predators
2) Increased ability to find resources
3) Decreased search time to find food or mates
4) Decreased predation
5) Decreased physiological costs of movement in air or water
6) Decreased physiological costs of thermoregulation via huddling
7) Division of labor: individuals can specialize on different tasks (food acquisition, nest defense, etc.)
8) Communal care of young: enhanced feeding and defense of offspring

Question 3

Costs of Sociality

Answer 3

1) Increased competition for resources
2) Increased opportunity for aggressive behavior
3) Increased likelihood of pathogen transmission

Question 4

Minnow Foraging Study

Answer 4

As schoal size increases, the average foraging time decreases

This study demonstrates how it is often harder for lone animals to find food, thus sociality provides foraging benefits

Question 5

Insects/Bees Foraging Study

Answer 5

Bees share up-to-date information about floral resources in the local environment

Demonstrating foraging benefits of sociality

Question 6

Coyote Experiment

Answer 6

Coyotes living in larger groups have a greater volume of larger prey items in their scat, and a decrease in smaller prey

Foraging benefits of sociality: increased capture

Question 7

Aerodynamic Benefit: Reduced cost of movement in pelicans

Answer 7

Research Question: Why do large birds fly in a V-formation?

Hypothesis: This formation reduces the cost of flying

Prediction: Birds in formation will have a lower wingbeat frequency and heart rate than solitary birds

Methods:

1) Placed heart rate monitors on trained white pelicans
2) Videotaped flight formations, collected data on wingbeat frequency and location of each bird in formation

Results: Birds in formation behind the leader had a slower wingbeat frequency and lower heart rate; still not as low as gliding though

Conclusion: Birds can thus reduce flight costs by flying in V-formation

Question 8

The cost of sociality: Competition

Answer 8

Therefore competition for resources can limit group size, in which:

1) Low-resource environments will have smaller group sizes than high-resource environments
2) Positive relationship between resources in a Habitat and Group Size

Question 9

Group Size and Competition in Primates – red colobus monkeys and red-railed guenons

Answer 9

Research Question: Does competition affect the size of social groups?

Hypothesis: Competition for food limits group size

Prediction: Low-resource environments should have smaller group sizes than high-resource environments

Methods:
Monkeys were fed a variety of fruits and vegetation
Group size ranged from <10 to >36
Each month, recorded the density of food trees on transects and the average group size of each species i four different sites

Results:
Average group size was positively correlated with the density of food trees

Conclusion: Competition for food appears to be associated with group size

Question 10

The Cost of Sociality: Disease Transmission

Answer 10

Parasites and pathogens can reduce an animal’s fitness;
Transmitted by close contact;
Disease transmission rates should increase with group size;
Positive correlation between group size and proportion of infected individuals

Question 11

Sociality and disease transmission in guppies

Answer 11

Research Question: How does sociality affect disease transmission?

Hypothesis: Tighter spacing between individuals enhances disease transmission

Prediction: Disease transmission rates will be higher in tighter social groups

• Guppies live in shoals (schools)
• Frequently infected with worms
• Females are more social – provides an opportunity to test how sociality/group spacing affects disease transmission

Methods:

• Removed all external parasites
• Created single-sex groups of sex
• Recorded average nearest neighbor distance in each school
• On 3rd day, infected a single fish in each school with 100 parasitic worms
• Recorded the spread of parasitic worms to other school members after three days

Results:

1) Females spent more time shoaling than males, and nearest neighbor distance was smaller in females than male groups
2) A higher proportion of females became infected than males

Conclusion: Disease transmission is affected by degree of sociality; this is a cost of group living/sociality

Question 12

Do costs affect all members of a group equally?

Answer 12

NOOOOOOOOOOO
In the case of aggression, the better competitor wins an interaction, with boy parties receiving differing levels of risk of injury

Question 13

How is aggression reduced in a group?

Answer 13

Dominance Hierarchy: An organized social system with dominant and subordinate members

Question 14

How aggressive interactions affect stress, and how it is affected by the dominance hierarchy

Answer 14

Adrenal glands secrete glucocorticoids in response to help utilize fat stores to deal with that stress;
chronic glucocorticoids secretion can negatively affect health and reproduction = COST OF AGGRESSION

If dominance hierarchies help reduce aggression, it should also reduce stress;
Conversely, disruption in hierarchy could increase stress

Question 15

Stable Dominance Hierarchies and Stress in Baboons

Answer 15

Research Question: How do do dominance hierarchies affect stress levels?

Hypothesis: The formation of a dominance hierarchy reduces aggression and stress in individuals

Prediction: Aggression level and stress hormones such as glucocorticoids will be lowest when stable hierarchies exist

Methods:

1) Observed chacma baboons; noted periods when stable dominance hierarchies existed and other periods when changes occurred
2) Collected fecal samples and characterized glucocorticoid levels of individuals

Results:

1) Aggression was lowest during stable periods
2) Fecal glucocorticoid levels were also lowest during stable periods

Conclusion: Aggression and stress levels are lowest during periods when dominance hierarchies are stable

Question 16

Animal Altruism

Answer 16

A behavior that results in the increased fitness of another individual and involves a cost to the individual performing the behavior;
AKA Helping Behavior

Is often directed towards close kin

Question 17

Inclusive Fitness

Answer 17

An individual’s genetic success (progeny produced) plus the genetic success of its relatives (which share a portion of the individual’s genes)

Helping a close kin increases inclusive fitness

Question 18

Kin Selection

Answer 18

Natural selection for behavior by individuals that may decrease their own survival or reproductive success, but increases that of their kin (who share a portion of their genes);

Based off of inclusive fitness

Question 19

Hamilton’s Rule and Kin Selection

Answer 19

States that altruism only evolves when B x r (relatedness) > C

B x r = the amount of altruist’s genes passed on through helping behavior

Question 20

Degree of relatedness chart

Answer 20

Parent-offspring: 0.5
Sibling-Sibling: 0.5
Grandparent-grandchild: 0.25
Aunt/Uncle-Nephew/Niece: 0.25
First Cousins: 0.125
Friends: 0

Question 21

Testing Hamilton’s Rule: Altruistic Turkeys

Answer 21

Male turkeys may form social coalitions (a pair of males) and display together to attract females;
BUT only the dominant male mates

Research Question: Why do subordinates in social coalitions help the dominant male?

Hypothesis: Kin selection explains the helping behvior

Prediction: For a subordinate male: B x r > C

Methods:

1) Captured and marked individual turkeys, collected blood
2) Determined degree of relatedness among coalition males
3) Determined reproductive success of males in coalitions vs. solo males

Results:
1) Coalition males were close relatives (r = 0.42)
2) Solo males sired on average 0.9 offspring per male = C
3) Dominant males sired 7 offspring = B (6.1 more than solo males)
Thus,
(B x r) > C
[(6.1 x 0.42) = 2.56 > 0.9]

Conclusion:
Kin selection and Hamilton’s rule explain helping behavior by subordinate male turkeys

Question 22

Kin Discrimination Hypotheses: How individuals discriminate kin from non-kin

Answer 22

1) Direct Familiarization – Individuals learn to discriminate kin from non-kin via previous associations
2) Indirect Familiarization – Individuals learn a reference phenotypic cue from themselves or known close relative. They then assess the degree of similarity of the learned cue to the cue in others.

Question 23

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Answer 23

Research Question: How do stickle-backs discriminate kin from non-kin?

Hypothesis: Sticklebacks discriminate kin from non-kin through association

Methods: Raised individuals with all kin or with both kin and non-kin
Experiment 1) Tested fish raised with all kin for preferences to associate with a group of familiar kin vs. (unfamiliar) non-kin
Experiment 2) Tested fish raised with kin and non-kin for preference to associate with familiar kin vs. unfamiliar non-kin

Results:

1) Individuals reared with only kin preferred to associate with familiar kin over unfamiliar non-kin
2) Individuals reared with both kin and non-kin did not display any preference between familiar kin and familiar non-kin

Conclusions: Stickleback learn kin via prior associations

ASK: Does this not count as direct familiarization?

Question 24

Cooperative Breeding

Answer 24

A situation in social groups in which adults physiologically capable of reproducing forgo breeding and instead help others to raise offspring
- Helpers do not reproduce; they pay a cost of care and so are exhibiting altruistic behavior

Question 25

Possible helper benefits of cooperative breeding

Answer 25

1) Increases inclusive fitness (if helpers are related)

2) Ecological constraints (get group benefits while waiting for better breeding conditions/opportunities in the future)

Question 26

Cooperative reproduction in long-tailed tits

Answer 26

Observation: Long-tailed tits with predated nests often help feed another pair’s young

Research Question: Why do some adult long-tailed tits within a social group help other adults to raise their offspring?

Hypothesis: Kin selection explains the evolution of helpers at the nest

Prediction: Helpers are close relatives of the adult breeders

Methods:

• Performed observations on birds of known relatedness
• Noted instances of helping behavior and long-term survivorship of nestlings (recruitment into a social group the following year)

Results:

1) Helpers assisted pairs that contained at least one relative; in 90% of cases, they were close relatives
2) The probability of recruitment of a young the following year increased with the number of helpers at their nest

Conclusion: Kin Selection explains the helping behavior in these birds; helpers benefit by increasing their inclusive fitness

Question 27

Cooperative reproduction and social queuing in clownfish

Answer 27

Clownfish exhibit sequential hermaphroditism (sex of individuals change as the develop)

• Schools form a hierarchy with a breeding, female fish at the top – and a breeding male below
• Other fish in the group are subordinate and do not breed, but help defend the territory

Hypothesis: Subordinates can move up the dominance over time, a process known as social queuing

Prediction: Subordinates will obtain future reproductive benefits by staying in their group

Methods: Observed 97 social groups of clownfish;
Noted recruitment of new fish, changes in breeding status;
Experimentally manipulated 16 groups by removing the breeding male and observed changes in social status

Results:

1) When breeding female is lost, the breeding male changed sex and became the breeding female
2) Removal of breeding male resulted in the next-highest-ranking non-breeder to become a reproductive male
3) Any new recruits always entered the group as the most subordinate member

Conclusion: Subordinate group members can eventually achieve dominant reproductive status via social queuing

Question 28

Eusociality, criteria, and and it forms

Answer 28

Extreme altruism

Includes:

1) Overlapping generations
2) Cooperative brood care by non-parents
3) A reproductive division of labor; some adults reproduce while others do not (they are sterile) and care for the young of others

Forms castes: morphologically and behaviorally distinct individuals within eusocial groups

Question 29

Hypotheses of how eusociality forms in Hymenoptera (bees, wasps and ants)

Answer 29

1) Haplodiploidy Hypothesis: Haplodiploid genetic systems
– Males develop from unfertilized eggs (Haploid)
– Females develop from fertilized eggs (Diploid)
In which sisters share 50% genes from father and either 50%/0% from mother – averaging 75% shared genes amongst sisters; kin selection and inclusive fitness is high, thus help queen produce more offspring

REFER TO PAPER

Question 30

Haplodiploidy Hypothesis

Answer 30

The evolution of eusociality in Hymenoptera is based on their haplodiploid genetic system;
But can not explain evolution of sterile castes in many non-Hymenoptera species, such as termite;
Most likely due to a combination of kin selection and ecological constraints

Question 31

Byproduct Mutualism

Answer 31

When an individual’s cooperative behavior enhances both its own fitness and the fitness of others;
Is often the explanation for unrelated altruism;
Evolves via direct reciprocal altruism (direct reciprocity)

Question 32

Direct Reciprocity

Answer 32

A helps B in one encounter and then B helps A in a future encounter
- Both individuals eventually receive a benefit that exceeds the cost of helping

Question 33

How does Direct Reciprocity Evolve?

Answer 33

Repeated interactions provide the opportunity for reciprocity

• “Tit-for-tat” strategy: a player always cooperates in the first interaction with a specific partner
• In later interactions, each matches the behavior of the other from the previous interaction
• When two players use this strategy (ESS), it can achieve a high payoff –> Altruism can evolve

Required conditions:

1) Individuals must have the opportunity to interact repeatedly
2) The fitness benefit received must exceed the cost of helping
3) Individuals must be able to recognize one another in order to reciprocate

Question 34

Audience effect

Answer 34

Occurs when the presence of bystanders influence the behavior of a signaler

Question 35

Dispersal

Answer 35

Short-distance, one-way movements to a new area;
Reduces inbreeding and competition for resources (Competition hypothesis and Inbreeding Avoidance Hypothesis)

Natal Dispersal: Movement away from an individual’s place of birth; one-time event

Breeding dispersal: Looks for best mating sites; Opposes site fidelity

Question 36

Migration, and its cost/benefits

Answer 36

Long-distance, two-way movements

Costs and benefits of migrating:

• Benefits: Move to an area with more favorable conditions
• Costs: Loss of time and energy, risk of predation, injury, etc.

Costs and benefits of staying in one location:

• Benefits: Do not pay costs and incur risks of long distance movement
• Cost: must endure harsher conditions in current habitat

Question 37

Three conditions required for evolution of behavior

Answer 37

1) Variability: variation in behavior among individuals

2) Heritability: some of these behavioral variants are in

Question 38

Why migrate? What is the evolutionary premise?

Answer 38

Due to changes in the environment

If some individuals have higher fitness when migrating, then the population may exhibit partial migration

If all individuals have higher fitness, then the entire population will become migratory

Question 39

Types of partial migration

Answer 39

Some are year-round residents (non-migrants)

Others exhibit seasonal migratory behavior

Question 40

Fixed Polymorphism

Answer 40

When partial migration is displayed year after year
1) Migratory behavior could be a fixed, genetic trait of individual, and 2 genotypes are maintained by frequency-dependent selection

2) Migratory behavior could be dependent on individual condition: all individuals have the genetic disposition, but migratory behavior is only expressed in some; like the more unfit in pop

Question 41

Orientation vs Navigation

Answer 41

Orientation is determining and maintaining a proper direction

Navigation is determining a particular location and moving toward it

Both useful for migration

Question 42

Multimodal Orientation

Answer 42

Use of multiple compass systems at once to orient and navigate to a particular location

• Sun Compass
• Geomagnetic Compass
• Star Compass

Question 43

Bicoordinate Navigation

Answer 43

The ability to identify a specific geographic location using two varying environmental gradients

Question 44

Reciprocal Altruism in Vampire Bats

Answer 44

Explains food sharing in bats

Observed blood sharing interactions when the deprived bat was returned to the group

Food sharing occurred in unrelated bats, especially if prior food had been received from the recipient in the past

May have evolved as a form of direct reciprocity

Question 45

Indirect reciprocity, and what is used to determine this

Answer 45

A helps B, because B helped C in the past

Individuals keep track of other individual’s reputation for helping = an image score

Question 46

Cleaner Fish Reputations; Indirect Reciprocity

Answer 46

Cleaner fish feed on ectoparasites on client fish, but some will try to eat mucus

Client fish solicit cleaner fish

Client fish can observe interactions and form image scores of cleaner fish

Research Question: Is there any evidence that animals use their image scores to modify altruistic behavior?

Methods:
Observed interactions between cleaners and clients;
For each interaction, determined whether each cleaner cooperated or cheated;
Observed the behavior of the net client for that cleaner

Results:
When the next client arrived within six seconds, its behavior was affected by the previous interaction
Next clinet invited 100% of cooperative cleaner fish, and <25% of cheating cleaner fish

Conclusion:
Clients appear to form image scores of cleaners and assess their propensity to interact cooperatively