Deck 17: The Evolution of Sociality

Question 1

In an analysis of independent contrast, researchers found that fetuses in polyandrous species of primates had faster growth rates than those in monogamous species. What did the researchers conclude from these results?

A) Fetuses develop faster to "make room" for offspring from a different male.
B) Extracting more resources from the mother maximizes offspring's inclusive fitness in polyandrous species.
C) Fast fetal growth rates are always optimal.
D) Fetal growth rates represent phylogenetic constraints and are unrelated to mating systems.

Answer 1

B

Question 2

Charles Darwin was initially puzzled by the observation that worker honeybees die when they sting an intruder to their hive (the bee's stinger is ripped from the bee's abdomen, causing a fatal injury). Based on what you know about natural selection, why did this observation complicate Darwin's theory?

A) All defensive behaviors in nature result in the death of the defender.
B) Such self-sacrifice is widespread in many different groups of animals.
C) He found it hard to imagine how such behavior could evolve, since a defending worker's chance of survival is zero.
D) The stinging apparatus appeared to be too complex to have evolved.

Answer 2

C

Question 3

Among which of the following groups of organisms is cooperation via reciprocal altruism most likely to evolve (assuming all else is equal)?

A) birds from across a species' range that congregate for a short time at a resting spot during migration
B) short-lived, immobile tidal organisms that are in constant contact with one another and have a high mortality via predation
C) female tigers that each inhabit their own large home range
D) primates in a social group that frequently interact with the same individuals

Answer 3

D

Question 4

An evolutionarily stable strategy (ESS) is a

A) strategy that, if adopted by all members of the population, cannot be invaded by a mutant strategy.
B) strategy that, if adopted by part of a population, cannot be invaded by a mutant strategy.
C) mutant strategy that cannot invade a population.
D) strategy that, if adopted by all members of the population, can be invaded by a mutant strategy.

Question 5

Compared to most physical resources, how is information unique?

A) There is no cost associated with sharing information.
B) The production and sharing of information does not require energy.
C) Because information is not a tangible physical entity, it does not affect an individual's fitness.
D) Information does not become depleted by sharing.

Question 6

In order for a game to be a true prisoner's dilemma, which of the following conditions must be met? P =Punishment for mutual defection, R = Reward for mutual cooperation, S = "Sucker's" payoff, T= Temptation to defect

A) T > R > P > S
B) S > P > T > R
C) R > P > S > T
D) R > P > T > S

Question 7

Under what circumstance is there a mixed Nash equilibrium for the hawk-dove game?

A) when the cost of fighting equals the benefit of a victory
B) when the cost of fighting is greater than the benefit of a victory
C) when the strategy of the other player is unknown and the game is played multiple times
D) when all members of the population play hawk exclusively

Question 8

Konrad Lorenz argued that "for the good of the species," animal fights (such as male-male combat) are rarely lethal. Which of the following is the most compelling counterargument to this assertion?

A) Animals of the same species rarely possess the physical means to kill each other.
B) Populations tend to produce more offspring than the carrying capacity of their environment; having individuals die in fights would be beneficial for the species.
C) Only humans can override the instinctual aversion to killing conspecifics.
D) An individual showing no restraint during fights would eliminate its competitors and maximize its individual fitness.

Question 9

The model below predicts that the begging level of full (satiated) offspring (F) should essentially be zero, whereas hungry (H) and starving (S) offspring show intermediate and high levels of begging, respectively. Under what circumstances would we expect full (satiated) offspring to start begging?

A) when the fitness costs of begging are higher than the benefits
B) when the fitness costs of begging are lower than the benefits
C) only when the fitness costs of begging increase in a nonlinear fashion with begging intensity
D) Under no circumstances would this occur; the full (F) individuals are by definition at begging intensity zero.

Question 10

Which of the following statements illustrates the free-rider problem?

A) By reliably reciprocating a cooperative behavior, all individuals in the population increase their fitness.
B) Some daughters forego having offspring of their own as they help their mothers with brood care.
C) An individual spends only half an hour grooming others for each hour of grooming it has received.
D) Some individuals forgo reproduction to avoid overpopulation of a species' habitat.

Question 11

An alarm call benefits multiple individuals, both related and unrelated (r $\gt$ 0). Can this behavior still evolve according to Hamilton's rule? (There are 1, 2, . . . , A individuals that are related to the donor by r₁, r₂,…, r_A and receive benefits b₁, b₂,…, b_A)

A) No; unrelated individuals will automatically set the benefits to 0, as Hamilton's rule for
Multiple individuals is

B) No; this case no longer addresses inclusive fitness, and Hamilton's rule does not apply.
C) Yes, if there are more related individuals benefiting than unrelated individuals, as Hamilton's rule for multiple individuals is
$\sum _ { 1 } ^ { A } r _ { 1 } b _ { i } - c > 0$
D) Yes, as long as the benefits to related individuals satisfy
$\sum _ { 1 } ^ { A } r _ { i } b _ { i } - c > 0$

Question 12

Based on the model for conventional signals below, which signal level should an individual of medium ability adopt?

A) A
B) B
C) C
D) D

Question 13

Which of the following represents a Nash equilibrium in the hawk-dove game? Assume that the cost of a fight is greater than the benefit of the resource that is being fought over.

A) Both players always play dove.
B) Both players always play hawk.
C) Player 1 always plays hawk, player 2 always plays dove; both players know each other's role (player 1 or player 2) before the encounter.
D) Player 1 always plays hawk, while player 2 plays hawk some of the time and dove some of the time.

Question 14

Is haplodiploidy a necessary condition for the evolution of eusociality?

A) Yes; true eusociality is found only in the hymenoptera, all of which are haplodiploid.
B) Yes; eusociality can only evolve when indirect fitness is as high as occurs between haplodiploid sisters.
C) No; eusociality is also found in organisms that do not have a haplodiploid genetic system, such as naked mole rats.
D) No; eusociality has evolved in every major animal lineage.

Question 15

Which of the following equations illustrates the correct relationship?

A) Indirect fitness +Direct fitness = Inclusive fitness
B) Inclusive fitness+ Direct fitness = Indirect fitness
C) Indirect fitness + Inclusive fitness = Direct fitness
D) Direct fitness - Inclusive fitness =Direct fitness

Question 16

Consider the modified payoff structure for the hawk-dove game below. Which of the following strategies should the players adopt? (v = benefit of the resource that is being fought over.)

A) Each player should play dove half of the time.
B) Both players should always play hawk.
C) One player should always play hawk; the other should always play dove.
D) Each player should play hawk half of the time.

Question 17

Consider Robert Trivers' parent-offspring conflict model. How do you expect the zone of conflict between parent and offspring to differ when the future offspring is a half instead of a full sibling?

A) The zone of conflict will become wider.
B) The zone of conflict will become narrower.
C) The zone of conflict will remain of the same width but shift toward higher parental investment.
D) The zone of conflict will become wider and shift toward higher parental investment.

Question 18

Suppose that an allele is present in blue-footed booby offspring that causes a nestling to share its food with its nestmate if it is not particularly hungry during times of adequate food availability. This gene imposes a fitness cost of 0.3 on those who carry it, while conferring a benefit of 0.4 on the sibling who receives the additional food. Will this gene increase in frequency if the two nestmates are always half siblings (with the same mother but different fathers)?

A) Yes, because rb - c < 0.
B) Yes, because rb - c > 0.
C) No, because rb - c > 0.
D) No, because rb -c < 0.

Question 19

The results of Tibbetts and Izzo's 2010 experiment on facial patterns and the fighting behavior of paper wasps are shown below. Why did Tibbetts and Izzo manipulate the wasps' aggressiveness, in addition to facial pattern?

A) to test whether hormones could artificially alter the fighting qualities of wasps
B) to test whether alteration of facial patterns strengthens the fighting ability of wasps
C) to test whether the alteration of facial patterns would result in increased aggression
D) to test whether the facial pattern is a conventional signal that is kept honest by continuous testing from conspecifics

Question 20

What is the coefficient of relatedness for individuals A and B in the following pedigree?

A) 0.50
B) 0.25
C) 0.125
D) 0.0625

Question 21

When graphing the amount of resources a parent invests in a focal offspring against fitness costs to the parent and benefits to the offspring, what is the so-called zone of conflict?

A) where parent-offspring conflict takes place
B) where parents and offspring both benefit from decreasing allocation to the focal offspring
C) where parents and offspring both benefit from increasing allocation to the focal offspring
D) where b - c is maximized

Question 22

In the context of cooperation, ________ selection acts against cooperators who pay some cost that others (such as free riders) do not pay. Selfish individuals who do not cooperate are favored by this type of selection because they receive any benefits that accrue through the actions of cooperators, but they pay none of the costs.

A) between-group
B) within-group
C) altruistic
D) kin

Question 23

Allele X codes for a cooperative behavior among full siblings. Recipients of this behavior receive a benefit of seven fitness units, and the behavior costs the donor three fitness units. Use Hamilton's rule to determine whether allele X will spread in the population.

Question 24

Which of the following statements is FALSE regarding haplodiploid mating systems and eusociality?

A) All hymenopteran species are haplodiploid and many are also eusocial; thus, at least in insects, haplodiploidy might be involved in the evolution of eusociality.
B) Haplodiploidy alone is neither necessary nor sufficient for the evolution of eusociality, but it does partly explain why eusociality evolved in many lineages of hymenopterans.
C) Several diploid species are also eusocial, indicating that haplodiploidy alone is not sufficient to explain the evolution of eusociality.
D) All eusocial species are haplodiploid.

Question 25

Which of the following is NOT an accurate interpretation of Paul Sherman's work on alarm calls in Belding's ground squirrels, as shown in the figure?

A) Adult females emit calls more often than expected by chance; although they comprise 30% of the population, they are responsible for 65% of the alarm calls.
B) Adult males emit calls less often than expected by chance; although they comprise 20% of the population, they are responsible for only 2% of alarm calls.
C) Juveniles are responsible for more alarm calls than are adults.
D) Females are responsible for more alarm calls than are males.

Question 26

Based on the figure, what is the coefficient of relatedness (r) between individuals A and B?

A) 0.25
B) 0.50
C) 0.75
D) 1.00

Question 27

Allele Z codes for a cooperative behavior among half siblings (r = 0.25). Recipients of this behavior receive a benefit of four fitness units and the behavior costs the donor two fitness units. Using Hamilton's rule (rb - c > 0), would you expect allele Z to spread in the population?

A) Yes; allele Z would increase in frequency within the population.
B) No; allele Z would decrease in frequency within the population.
C) Allele Z would neither increase nor decrease in frequency.
D) There is not enough information to determine if the allele will spread.

Question 28

Which of the following is NOT an example of conflict between related individuals?

A) conflict over parental investment, such as the amount of resources each parent must provide for their offspring
B) siblings competing over resources, which can lead to siblicide in extreme cases
C) conflict over which offspring to nurture in times of resource scarcity
D) males competing for access to mates

Question 29

What is the term used to describe an individual's total fitness, as a product of both producing offspring itself and helping its kin in their reproductive efforts?

A) indirect fitness
B) direct fitness
C) inclusive fitness
D) reciprocal fitness

Question 30

For any given allele copy in a diploid, sexually reproducing parent, what is the chance that the allele will be passed on to each of its offspring?

A) 0.75
B) 0.25
C) 1.00
D) 0.50

Question 31

You want to study whether reciprocity explains the evolution of mobbing behavior in birds. You have two sources of birds from which to choose: (A) a group of birds from your lab that all originated from the same mating pair, and (B) a group of presumably unrelated birds from the wild. Which choice would you prefer? Briefly justify your answer.

Question 32

Assume that the cost of fighting is four times greater than the benefit gained from the resource that is being fought over. What is the probability with which an individual should play dove in the mixed Nash equilibrium of the hawk-dove game?

Question 33

Which of the following serves as one explanation for how honest signaling evolves and is maintained in a population?

A) kin selection
B) trait-group selection
C) information sharing
D) costly signaling theory

Question 34

Calculate the coefficient of relatedness for the following relationships in a haplodiploid hymenopteran species:

A) Sister to full sisters
B) Sister to brother
C) Brother to sister

Question 35

What is the coefficient of relatedness between a haplodiploid female worker bee and a male drone in the same hive, if they do not have the same mother?

A) 1.00
B) 0.50
C) 0.25
D) potentially, zero

Question 36

If the prisoner's dilemma game is played only once, what would we NOT expect to see?

A) one possible Nash equilibrium
B) both players defect
C) both players cooperate
D) each player receives P, the punishment for mutual defection

Question 37

In which of the following scenarios would reciprocal altruism be LEAST likely to evolve?

A) in long-lived, intelligent species that live in small groups with high mutual dependence
B) when there are repeated interactions with the same individuals within a group
C) when opportunities for altruism and reciprocation are rare
D) when failure to reciprocate is punished

Question 38

Which of the following concepts could be applied to test the kinship and cooperation model?

A) Hamilton's rule
B) Nash equilibrium
C) prisoner's dilemma
D) trait-group selection models

Question 39

Based on the figures shown here, calculate the coefficient of relatedness for individuals A and B in each case. Show your calculations.

Question 40

________ is the probability that the homologous alleles in two individuals are identical by descent due to inheritance of the alleles from a common ancestor.

A) The coefficient of relatedness
B) Indirect fitness
C) Haplodiploidy
D) Hamilton's rule

Question 41

Why does conflict arise between different alleles at the same locus even though they are part of a single individual's genome?

Question 42

How did John Krebs and Richard Dawkins (1978) illustrate the "mind reading versus manipulation" view of communication with the example of a dog baring its teeth?

Question 43

Between which amounts of parental investment can you find the "zone of conflict" between parent and focal offspring? Delineate the zone of conflict in the figure below, and briefly explain how you chose the lower and upper bound.

Question 44

Imagine you are studying horns in male deer, and you hypothesize that horns are costly honest signals that help to prevent male fights. What three predictions should you use to test your hypothesis?

Question 45

Describe how DNA methylation of gametes can create parent-of-origin effects.

Question 46

What is the most likely explanation for why female Belding's ground squirrels make alarm calls to alert nearby individuals of a predator much more frequently than males do?

Question 47

What gametes will survive after meiosis of the following chromosome pair? Sd = active segregation distorter allele, Sd ⁺ = inactive segregation distorter allele, Rsp^s =response sensitive responder gene allele, Rspⁱ =response insensitive responder genes allele

Question 48

What three evolutionary paths can lead to the evolution of cooperation?

Question 49

Describe the control in Tibbetts and Izzo's experiment, illustrated below, in which they manipulated the facial pattern and fighting behavior of wasps.

Question 50

Name the three familial conflicts.