Deck 6: Avoiding Predators and Finding Food

Question 1

Refer to the following paragraph.
In the evening, males of a species of bee (Idiomelissodes duplocincta) form sleeping clusters in which dozens or hundreds of bees perch close together overnight. An assassin bug kills bees at these sleeping sites, but usually only one or two bees per night.
(A) The bees do not join forces to fight the bug when one appears, so it may be that a bee joins the cluster to lessen the risk that it will be one of the unlucky ones killed at random.
(B) The same sort of clustering of defenseless prey occurs in spadefoot frog tadpoles; hundreds of tadpoles swim and feed together in pools containing carnivorous water beetles that attack and kill them.
(C) In contrast, males of other bees in the genus Idiomelissodes are larger and more capable of deterring a predator on their own, and they sleep apart.
Which sentence in the paragraph contains an example of divergent evolution?

A) A
B) B
C) C
D) None of the above

Answer 1

C

Question 2

Refer to the following paragraph.
In the evening, males of a species of bee (Idiomelissodes duplocincta) form sleeping clusters in which dozens or hundreds of bees perch close together overnight. An assassin bug kills bees at these sleeping sites, but usually only one or two bees per night.
(A) The bees do not join forces to fight the bug when one appears, so it may be that a bee joins the cluster to lessen the risk that it will be one of the unlucky ones killed at random.
(B) The same sort of clustering of defenseless prey occurs in spadefoot frog tadpoles; hundreds of tadpoles swim and feed together in pools containing carnivorous water beetles that attack and kill them.
(C) In contrast, males of other bees in the genus Idiomelissodes are larger and more capable of deterring a predator on their own, and they sleep apart.
Which sentence in the paragraph contains an example of convergent evolution?

A) A
B) B
C) C
D) All of the above

Answer 2

B

Question 3

Refer to the following paragraph.
In the evening, males of a species of bee (Idiomelissodes duplocincta) form sleeping clusters in which dozens or hundreds of bees perch close together overnight. An assassin bug kills bees at these sleeping sites, but usually only one or two bees per night.
(A) The bees do not join forces to fight the bug when one appears, so it may be that a bee joins the cluster to lessen the risk that it will be one of the unlucky ones killed at random.
(B) The same sort of clustering of defenseless prey occurs in spadefoot frog tadpoles; hundreds of tadpoles swim and feed together in pools containing carnivorous water beetles that attack and kill them.
(C) In contrast, males of other bees in the genus Idiomelissodes are larger and more capable of deterring a predator on their own, and they sleep apart.
Sentence A most closely describes the

A) confusion effect hypothesis.
B) signal deception hypothesis.
C) selfish herd hypothesis.
D) dilution effect hypothesis.

Answer 3

D

Question 4

Refer to the following paragraph.
In the evening, males of a species of bee (Idiomelissodes duplocincta) form sleeping clusters in which dozens or hundreds of bees perch close together overnight. An assassin bug kills bees at these sleeping sites, but usually only one or two bees per night.
(A) The bees do not join forces to fight the bug when one appears, so it may be that a bee joins the cluster to lessen the risk that it will be one of the unlucky ones killed at random.
(B) The same sort of clustering of defenseless prey occurs in spadefoot frog tadpoles; hundreds of tadpoles swim and feed together in pools containing carnivorous water beetles that attack and kill them.
(C) In contrast, males of other bees in the genus Idiomelissodes are larger and more capable of deterring a predator on their own, and they sleep apart.
Males of other bees in the genus Idiomelissodes most likely do not also form sleeping clusters because

A) there is a cost to forming such large groups, such as being easier to target by predators.
B) they are more highly evolved and no longer need social defense strategies.
C) males of Idiomelissodes duplocincta do not admit males of other species into their groups.
D) there is minimal benefit derived from residing in such large groups; the males of Idiomelissodes duplocincta are simply making the best of a bad job.

Question 5

In order to test the selfish herd hypothesis, this researcher should determine if

A) the assassin bug's efficiency decreases as the bee group size increases.
B) bees that are painted to cover their stripes are more likely to be attacked by the assassin bug.
C) bees near the periphery of the sleeping cluster are more likely to be targeted by the assassin bug than those near the center.
D) bees that are not attacked are more closely related to one another than those that are targeted.

Question 6

If a foraging tactic is "optimal," this behavior

A) helps to maintain the population at a level likely to promote the long-term survival of the species.
B) supplies a fitness benefit to individuals.
C) is an efficient way to collect food.
D) confers more fitness on individuals than any other alternative trait in the population.

Question 7

Refer to the figure.
The figure shows a matrix of fitness payoffs for interactions between two behaviorally different types of gulls: those that always fish for themselves and those that sometimes steal fish from others. P stands for the baseline fitness that a gull derives when it fishes for itself. B is the fitness gained by a thief when it steals a fish from a fish-for-self type. C is the fitness cost associated with an attempt to steal a prey.
What causal question is the model designed to answer?

A) How can a hereditary thief phenotype spread in a population of fish-for-self types?
B) What are the fitness costs and fitness benefits of fish-for-self versus thief phenotypes?
C) When can group selection cause evolutionary change to take place?
D) What are the circumstances under which maladaptive traits can take over a population?

Question 8

Refer to the figure.
The figure shows a matrix of fitness payoffs for interactions between two behaviorally different types of gulls: those that always fish for themselves and those that sometimes steal fish from others. P stands for the baseline fitness that a gull derives when it fishes for itself. B is the fitness gained by a thief when it steals a fish from a fish-for-self type. C is the fitness cost associated with an attempt to steal a prey.
What is the significance of the fact that in a population composed entirely of thieves, the average fitness payoff for a thief is P - C, whereas in a population composed entirely of fish-for-self types, the average payoff is P?

A) It tells us that fish-for-self types will become more common over time.
B) It tells us that the spread of a trait depends not on its absolute fitness effect but rather on its fitness effect relative to an alternative trait.
C) It tells us that the thief phenotype is an evolutionarily maladaptive trait.
D) It tells us that the thief phenotype is costly for the population as a whole.

Question 9

Refer to the figure.
The figure shows a matrix of fitness payoffs for interactions between two behaviorally different types of gulls: those that always fish for themselves and those that sometimes steal fish from others. P stands for the baseline fitness that a gull derives when it fishes for itself. B is the fitness gained by a thief when it steals a fish from a fish-for-self type. C is the fitness cost associated with an attempt to steal a prey.
If B were greater than C, the solitary phenotype would

A) perpetuate itself but not increase over time.
B) increase steadily over time.
C) disappear from the population over time.
D) increase until it made up 50 percent of the population.

Question 10

You read that a foraging tactic is "optimal" only if it is the most efficient way of acquiring calories from the environment. This is _______ because _______.

A) true; this will enable the species to grow and avoid extinction
B) true; selection favors traits that have large benefits
C) false; species that collect food too efficiently run the risk of destroying the resource base needed for that species
D) false; sometimes animals gain more fitness by sacrificing some foraging efficiency in order to better avoid predators

Question 11

A conditional strategy is unquestionably an adaptation when individuals able to switch tactics

A) leave some surviving descendants to carry their genes into the next generation.
B) leave more surviving offspring than individuals with any other available strategy.
C) are better able to adjust to changing conditions than other members of their species.
D) experience a net gain in fitness from their behavioral flexibility.

Question 12

A seed-eating bird forages solitarily. A behavioral biologist who is formulating a hypothesis is likely to consider this an example of

A) game theory.
B) optimality theory.
C) group selection theory.
D) conditional strategy theory.

Question 13

A seed-eating bird forages in groups with competitive companions. A behavioral biologist who is formulating a hypothesis is likely to consider this an example of

A) game theory.
B) optimality theory.
C) group selection theory.
D) conditional strategy theory.

Question 14

Smaller seed-eating birds select smaller seeds than larger seed-eating birds do. A behavioral biologist who is formulating a hypothesis is likely to consider this an example of

A) game theory.
B) optimality theory.
C) group selection theory.
D) conditional strategy theory.

Question 15

A certain fish-eating hawk that lives by large lakes can capture more pounds of fish per unit time if it were to hunt farther from shore instead of staying close to the shoreline. The hawk, however, does stay close to the shoreline. This demonstrates that

A) natural selection theory is probably not applicable in this case.
B) optimal foraging theory is probably not applicable in this case.
C) an optimal foraging hypothesis based on maximizing caloric intake alone is probably incorrect in this case.
D) the fish species found close to the shoreline in large lakes are more nutritious than those in the center.

Question 16

If a population is subject to frequency-dependent selection, then

A) two alternative forms of a trait can persist indefinitely in the population.
B) the rarer of two forms of a trait will become somewhat rarer in the next generation.
C) the frequency of an adaptation will become greater over time, depending on the extent to which individuals with that trait out-reproduce individuals with the alternative attribute.
D) neither form of the trait is considered an adaptation but instead these forms are kept in the species to provide flexibility, should the environment change.

Question 17

Refer to the figure.
Northwestern crows fly to 5 meters high (indicated by the arrow) to drop whelks in an effort to open and eat them. Based on the figure, crows should prefer to choose

A) large whelks, because their high caloric benefit outweighs their high cost in handling time.
B) large whelks, because they require the lowest handling time for the highest energy benefit.
C) medium whelks, because they provide the optimal balance between energy benefit and cost in handling time.
D) small whelks, because they are easiest to find and therefore have the lowest cost in search time.

Question 18

Refer to the figure.
The study that produced this figure was most likely testing the hypothesis that

A) crows choose to forage on different sized whelks depending on their individual fitness and body size.
B) crows that choose to forage on optimally-sized whelks maximize their reproductive success.
C) choosing to eat the optimally-sized whelk is an adaptive foraging strategy for crows.
D) crow foraging strategy is mediated by the landscape of fear and antipredator behavior.

Question 19

Following the cognitive buffer hypothesis, we can predict that

A) species with larger relative brain size are more likely to occur in regions with higher environmental variation.
B) species that engage in food caching are more likely to occur in predictable environments.
C) better cognitive ability is a tradeoff with reproductive success
D) species found in harsh, unpredictable environments are more likely to be impacted by landscapes of fear, at the expense of efficient foraging.

Question 20

Observation: You observe "shaky leaf walking" in a video of a Madagascaran mantid (one of about 1,800 species, a member of one of dozens of genera of mantids, which constitute one of eight families of mantids).
Hypothesis: The behavior is effective as camouflage because it makes the mantid look like a dried leaf blown about on the leaf litter of the forest floor or a trembling leaf on a low-lying shrub.
State a prediction from this hypothesis that could be tested via additional observation.

Question 21

Observation: You observe "shaky leaf walking" in a video of a Madagascaran mantid (one of about 1,800 species, a member of one of dozens of genera of mantids, which constitute one of eight families of mantids).
Hypothesis: The behavior is effective as camouflage because it makes the mantid look like a dried leaf blown about on the leaf litter of the forest floor or a trembling leaf on a low-lying shrub.
State a prediction that could be tested via an experiment.

Question 22

Several hundred male bees will sometimes gather in the evening to sleep on the dried stems of a shrub. A predatory assassin bug sometimes visits the bees and kills some as they are settling down. Present three hypotheses on the possible adaptive, antipredator value of these sleeping aggregations. For each hypothesis, present a piece of evidence that would enable you to reject the hypothesis.

Question 23

In the "Finding Food" episode of his series Trials of Life, Sir David Attenborough features a hummingbird species that feeds almost exclusively on the nectar of the Heliconia flower. He explains that each hummingbird has a circuit that takes it from one plant to another, with the bird arriving regularly at a given flower after a set period. It could take 30 minutes, more or less, to complete the round trip. In one sentence, explain why the following statement could be wrong: "The bird is behaving optimally because it is getting enough energy to continue making its foraging circuit."

Question 24

In the "Finding Food" episode of his series Trials of Life, Sir David Attenborough features a hummingbird species that feeds almost exclusively on the nectar of the Heliconia flower. He explains that each hummingbird has a circuit that takes it from one plant to another, with the bird arriving regularly at a given flower after a set period. It could take 30 minutes, more or less, to complete the round trip. The hummingbird does not immediately insert its beak into many Heliconia flowers but hesitates before approaching the flowers more closely. How might this hesitation still be consistent with at least one optimal foraging hypothesis? (Consider the different factors that might contribute to true optimality.)

Question 25

Caro (1986) presented several hypotheses for stotting behavior in the Thomson's gazelle:
(A) Alarm signal hypothesis: Gazelles stot to communicate predation risk to conspecifics.
(B) Confusion effect hypothesis: If several gazelles stot simultaneously in a group while fleeing, then the predator may become confused.
(C) Social cohesion hypothesis: Gazelles stot to attract conspecifics to join them.
(d) Attack deterrence hypothesis: Gazelles stot to signal their vigor to potential predators.
Choose one of the above hypotheses, and design an observational study to test this hypothesis against the others. What findings would support this hypothesis over the others? What findings would lead you to reject this hypothesis?