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Flashcards in Exam 3 Deck (52)
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1

Which of the following is considered a scenario leading to sexual dimorphism in animals?
A) different life histories and ecological relationships of males and females
B) sexual selection mediated by contests among males for access to females
C) sexual selection mediated by direct exercise of female mate choice
D) all of the above

D) all of the above

2

You are studying a species of bird that is often monogamous but sometimes exhibits polygyny. You have the choice of studying this species in several different habitats. Which of the following will you choose if you want the highest likelihood of finding polygyny?
A) a habitat in which territory qualities are nearly identical
B) a habitat in which territory qualities vary somewhat
C) a habitat in which territory qualities are highly variable
D) a habitat unsuitable for the formation of territories

C) a habitat in which territory qualities are highly variable

3

In species with separate sexes, which sex can enhance more its evolutionary fitness by mating with many partners of the opposite sex?
A) males B) females C) Neither sex has an advantage in this respect.

A) males

4

Of the two possible kinds of polygamy, which is by far the more common in animals?
A) polygyny (one male forms long-term bonds with more than one female)
B) polyandry (one female forms long-term bonds with more than one male)

A) polygyny (one male forms long-term bonds with more than one female)

5

What happened when the tails of male widowbirds were artificially elongated?
A) These males were more successful in attracting mates than males with normal tails.
B) These males were less successful in attracting mates than males with normal tails.
C) These males were about equally successful in attracting mates as males with normal tails.

A) These males were more successful in attracting mates than males with normal tails.

6

American woodcocks have a promiscuous mating system. Male woodcocks gather in a communal display ground called a “lek”. They engage in an elaborate and conspicuous display flight called “winnowing,” as they vie for matings with their female spectators. This mating ritual performed by the males is likely the result of sexual selection, but which kind of sexual selection is it?
A) direct exercise of mate choice by females
B) contests among males for access to females

A) direct exercise of mate choice by females

7

Flocking behavior in European goldfinches has costs and benefits. Which of the following would be considered a cost associated with increasing flock size?
A) fewer head jerks per minute for individuals
B) increased total vigilance rate for the entire flock
C) reduced food handling time for individuals
D) increased flight time between food plants for individuals caused by more rapid resource depletion

D) increased flight time between food plants for individuals caused by more rapid resource depletion

8

A crow attacks a red-tailed hawk flying nearby. Which of these two birds is the donor of the attacking behavior?
A) the crow
B) the red-tailed hawk

A) the crow

9

Which of the following kinds of behavior is least likely to be favored by natural selection under any circumstance?
A) cooperative
B) altruistic
C) selfish
D) spiteful

D) spiteful

10

If C is the cost of a particular behavior for the donor, B is the benefit of the behavior to the recipient, and r is the coefficient of relationship, what does the relationship C

C) conditions under which an altruistic behavior will increase in the population

11

The famous evolutionary biologist J. B. S. Haldane said the following one evening while drinking at a pub: “I would jump into a river and risk my life to save two brothers, but not one. I would jump in to save eight cousins, but not seven.” To what important concept was he alluding?
A) An altruistic behavior does not begin to make evolutionary sense until the inclusive fitness associated with the behavior (from the donor’s perspective) is at least zero.
B) His rambling comments were clearly the product of intoxication and had no meaningful evolutionary interpretation.

A) An altruistic behavior does not begin to make evolutionary sense until the inclusive fitness associated with the behavior (from the donor’s perspective) is at least zero.

12

Effective population size (Ne) is almost always lower than actual population size (N) because, for example:
A. sex ratios are equal
B. breeding systems are typically monogamous
C. family sizes vary, with some parents contributing more offspring
D. environmental conditions are constant

C. family sizes vary, with some parents contributing more offspring

13

The number of alleles per gene, for example the number of MHC alleles in human populations, describes a measure of:
A) different life histories and ecological relationships of males and females
B) sexual selection mediated by contests among males for access to females
C) sexual selection mediated by direct exercise of female mate choice
D) all of the above

A) different life histories and ecological relationships of males and females

14

The number of alleles per gene, for example the number of MHC alleles in human populations, describes a measure of:
A. inbreeding
B. natural selection
C. genetic diversity
D. outbreeding depression

C. genetic diversity

15

Why are cheetahs an example of how low genetic diversity does not necessarily mean the population is headed for extinction?
A. While the genetic diversity continues to decline, there is no evidence of inbreeding depression.
B. The genetic diversity, while low, is not declining in part because females mate with many males.
C. They evolved with low genetic diversity to begin with, so they have adapted to it.
D. none of the above

B. The genetic diversity, while low, is not declining in part because females mate with many males.

16

What is an extinction vortex?
A. the random decline of a population even if they have high genetic diversity
B. the inevitable trajectory of all species
C. a description of the self-reinforcing decline of large populations
D. the loss of genetic diversity, lowering fitness, which further reduces the population size

D. the loss of genetic diversity, lowering fitness, which further reduces the population size

17

In the absence of natural selection, genetic drift will cause alleles to become fixed or lost most rapidly in the population(s) of which size?
A. 4
B. 40
C. 400
D. 4000
E. all of the above

A. 4

18

In experiments with the plant Banksia spinulosa, Australian researchers Glenda Vaughton and Susan Carthew showed that individual plants:
A) can make distinctions among developing embryos on the basis of their genotypes.
B) cannot make distinctions among developing embryos on the basis of their genotypes.

A) can make distinctions among developing embryos on the basis of their genotypes.

19

A small population of wolves founded by a single breeding pair on the Scandinavian peninsula in 1983 showed little vitality until 1991, when the population began to grow exponentially. What event in 1991 led to the increased vitality of the population?
A) several years of unusually mild winters
B) infusion of new genes into the pack by a single immigrant male
C) cessation of hunting by humans
D) recovery of the Scandinavian caribou herd
E) all of the above

B) infusion of new genes into the pack by a single immigrant male

20

As illustrated in the research conducted by Price and Wasser on Delphinium nelsoni, (Figure 13.15, above) outbreeding is always desirable, even if matings occur between individuals separated by great distance.
A) True B) False

B) False

21

If a farmer is choosing a predatory insect to control pest insects in her fields, she should choose a predator that has:
A) high reproductive capacity relative to the pest.
B) high dispersal capacity.
C) the ability to switch to alternate food resources.
D) all of the above

D) all of the above

22

Scientists first noticed predator/prey oscillations because of disease patterns in humans.
A. True
B. False

B. False

23

Huffaker’s experiment on predators and prey was important, because:
A) he showed scientists could recreate population cycles seen in nature in the laboratory.
B) he showed predators were the most important source of prey mortality.
C) he showed prey populations could oscillate in the absence of predators.
D) all of the above

A) he showed scientists could recreate population cycles seen in nature in the laboratory.

24

Populations can be limited from:
A. 'above' by consumers
B. 'below' by resources
C. both A and B

C. both A and B

25

In predator-prey population cycles:
A. the number of prey often peaks a few years before predator numbers peak.
B. the number of predators often peaks a few years before prey numbers peak.
C. neither A nor B

A. the number of prey often peaks a few years before predator numbers peak.

26

In class, we learned about two sets of model equations developed by Alfred Lotka and Vito Volterra, two American population biologists. One set of paired equations describes dynamics of predator and prey, the other describes dynamics of two competitors:
Lotka-Volterra predator-prey model:
dV/dt = rV – cVP (V is the number of individuals of the victim, or prey)
dP/dt = acVP – dP (P is the number of individuals of the predator)
Lotka-Volterra competition model:
dN1/dt = r1*N1* (K1 – (N1 + αN2)/K1) (N1 is the number of individuals of species 1)
dN2/dt = r2*N2* (K2 – (N2 + βN1)/K2) (N2 is the number of individuals of species 2)
Which of these two models is based on the logistic model of population growth?
A) predator-prey model B) competition model

B) competition model

27

Which of the two models in question 26 above is based on the exponential model of population growth?
A) predator-prey model B) competition model

A) predator-prey model

28

In the Lotka-Volterra model for predator-prey interactions (question 26, above), what is one of the most interesting predictions for changes in population sizes of predator (P) and Prey (V) through time? (Hint: we see this pattern in natural populations of lynx and snowshoe hare in Canada.)
A) the predator always goes extinct
B) the prey always goes extinct
C) predator and prey exhibit endless population cycles

C) predator and prey exhibit endless population cycles

29

In the Lotka-Volterra model for competitor interactions (question 26, above), what do the terms α and β stand for?
A) competition coefficients
B) population sizes of the two species
C) carrying capacities for the two species

A) competition coefficients

30

In the Lotka-Volterra model for competitor interactions (question 26, above), imagine a situation where the carrying capacity for species 1 (K1) in the absence of species 2 is 100 individuals. Then imagine the same situation, except that now 40 individuals of species 2 are also present. In this case, dN1/dt = 0 when N1 = 80 individuals. What is α?
A) 0.0 D) 1.5
B) 0.5 E) 2.0
C) 1.0

B) 0.5