Question 1

Refer to the figure.
 Based on the data in the figure, what is the carrying capacity in this environment?
A) 5
B) 10
C) 28
D) 39

Accepted Answer

The answer of Refer to the figure.
 Based on the...

Question 2

A population of wolves predates a population of moose on Isle Royale, Michigan, where there are fewer wolves than moose to start. The wolves prey on the moose and eat well, allowing them to have abundant offspring. However, as the wolf population rises, the moose population drops, and over time, the wolf population begins to drop also because of the reduced availability of resources. As the wolf population drops, moose are able to better survive and reproduce, causing the moose population to rise. With this abundance of moose, the wolf population is able to rebound until their population exceeds the moose population's ability to support the number of wolves. Which population dynamic does this series of oscillations represent?
A) Delayed density dependence
B) Delayed density independence
C) Extinction vortex
D) Carrying capacity

Accepted Answer

This scenario describes delayed density dependence, where the population size of predators (wolves) and prey (moose) oscillate due to time lags in the response of the predator population to changes in the prey population.

Question 3

Which of the following is most likely to lead to population cycles?
A) Demographic stochasticity
B) Delayed density dependence
C) Habitat fragmentation
D) Logistic growth

Accepted Answer

Delayed density dependence can lead to population cycles as it involves time lags in the response of population growth rates to changes in population density, causing oscillations.

Question 4

Suppose a population of weevils that experiences logistic growth has an initial size of 1,563 and follows the standard equation for delayed density dependence with a 5-week delay and an intrinsic growth rate of 0.15 per week. If these conditions remain constant and the population is tracked for a long time, what type of population dynamics should it display? (Note: The cutoff r    value for dampened oscillations is 0.368, and the cutoff for a stable limit cycle is 1.57.)
A) Exponential growth
B) Logistic growth
C) Dampened oscillations
D) A stable limit cycle

Accepted Answer

The answer of Suppose a population of weevils that experiences...

Question 5

In the 1950s, Nicholson's experiments with blowflies showed that delayed density dependence can produce population cycles. If the experimental subjects in these studies had been blowflies with somewhat lower growth rates, he most likely would have observed which pattern of population dynamics?
A) Dampened oscillations
B) Exponential growth
C) Population outbreaks at unpredictable intervals
D) Demographic stochasticity

Accepted Answer

With lower growth rates, the population would likely exhibit dampened oscillations, where the amplitude of population cycles decreases over time, eventually stabilizing.

Question 6

Nicholson (1957) found that when adult sheep blowfly populations are high, egg production by blowflies
A) increases dramatically.
B) increases slightly.
C) stays the same as when populations are low.
D) decreases and few or no eggs are produced.

Accepted Answer

Nicholson (1957) observed that when adult sheep blowfly populations are high, the competition for resources increases, leading to a decrease in egg production, with few or no eggs being produced.

Question 7

Which statement about Nicholson's experiments with blowflies is true?
A) Population cycles occurred when adults had limited food and maggots had unlimited food.
B) Population cycles occurred when both maggots and adults had unlimited food.
C) Population cycles occurred when both maggots and adults had limited food.
D) Population cycles occurred when adults had unlimited food and maggots had limited food.

Accepted Answer

The answer of Which statement about Nicholson's experiments with blowflies...

Question 8

Assuming that their average population growth rates and all other factors are equal, which population would most likely be at risk for extinction?
A) A large population with low variation in its growth rate
B) A large population with high variation in its growth rate
C) A small population with high variation in its growth rate
D) A small population with low variation in its growth rate

Accepted Answer

A small population with high variation in its growth rate is most at risk for extinction because small populations are more vulnerable to random events and genetic drift, and high variation in growth rates can lead to unpredictable and potentially unsustainable population sizes.

Question 9

A small population of 100 organisms is only able to contribute 25 offspring to the next generation, but during that time, 30 individuals in the population die. In the next iteration, the remaining 95 individuals generate only 20 offspring, but during that time, 30 individuals of the population die. The remaining 85 individuals generate only 15 offspring, but during that time, 30 individuals of the population die. Which of the following terms best describes what this population is experiencing?
A) Ineffective population size
B) Negative exponential growth
C) Carrying capacity
D) Extinction vortex

Accepted Answer

The population is experiencing an extinction vortex, where the population size decreases progressively due to a combination of low reproduction rates and high mortality rates, leading to a downward spiral towards extinction.

Question 10

Which of the following statements about effective population size is true?
A) It is the minimum number of organisms needed for a population to survive.
B) It is the number of individuals needed to maximize genetic diversity.
C) It is the maximum number of individuals an ecosystem can support.
D) It is the number of individuals that can contribute offspring to the next generation.

Accepted Answer

Effective population size refers to the number of individuals in a population who contribute offspring to the next generation, influencing genetic diversity and evolutionary potential.

Question 11

Which of the following statements is a conclusion of Jones and Diamond's studies of extinction in bird populations in the Channel Islands?
A) Larger populations are at less risk of going extinct than smaller ones are.
B) Genetic drift is the most important factor in determining extinction risk.
C) Genetic drift is not an important factor in determining extinction risk.
D) Demographic stochasticity is the most important factor in determining extinction risk.

Accepted Answer

Jones and Diamond's studies concluded that larger populations are at less risk of going extinct than smaller ones, highlighting the importance of population size in extinction risk.

Question 12

Suppose that only two females and a small number of males are left in a population of a highly endangered bird. Although all of these birds are healthy, by chance, both females fail to reproduce and the population goes extinct. This extinction is best described as a consequence of
A) inbreeding.
B) genetic drift.
C) environmental stochasticity.
D) demographic stochasticity.

Accepted Answer

Demographic stochasticity refers to the random fluctuations in population size due to random events affecting reproduction and survival, such as the failure of the two females to reproduce in this scenario.

Question 13

At low population densities, the flocking behavior of some species of birds is disrupted to the extent that the population growth rate is lower at very low densities than it is at somewhat higher densities. This is an example of
A) an Allee effect.
B) genetic drift.
C) environmental stochasticity.
D) dampened oscillations.

Accepted Answer

The Allee effect refers to a phenomenon in ecology where individuals have a lower fitness at low population densities, which can lead to reduced population growth rates. This is consistent with the description provided.

Question 14

Refer to the figure.
 The figure is derived from studies of the populations and per-individual growth rates of three species of rodents in the U.S. desert southwest. According to the figure, which population(s) show(s) evidence of Allee effects?
A) Population A only
B) Population B only
C) Population C only
D) Populations A and B

Accepted Answer

The answer of Refer to the figure.
 The figure is...

Question 15

Which statement about genetic drift is false?
A) It can rapidly reduce the genetic variability of small populations.
B) It is a process by which chance events influence which alleles are transmitted to the next generation.
C) It is an Allee effect.
D) It can cause harmful alleles to occur at high frequency.

Accepted Answer

Genetic drift is not an Allee effect. The Allee effect refers to a phenomenon in ecology where the population growth rate decreases as the population density decreases. Genetic drift, on the other hand, is a mechanism of evolution that involves random changes in allele frequencies in a population.

Question 16

Refer to the figure.
 Based on the figure, extinction was a possible outcome for _______ breeding pairs.
A) 10
B) 100
C) 1,000
D) 10,000

Accepted Answer

The answer of Refer to the figure.
 Based on the...

Question 17

Imagine a moose in Grand Teton National Park, Wyoming is wandering around in a field of flowers. As it walks, it crushes and kills several flowers that turn out to be the last of their kind, causing that species of flower to go extinct. What is this an example of?
A) Extinction vortex
B) Genetic drift
C) Density dependent factor
D) Allee effects

Accepted Answer

This is an example of genetic drift, which is a random change in allele frequencies in a population. The moose's accidental destruction of the last flowers of a species is a random event leading to the extinction of that species.

Question 18

Although there are approximately 10,000 cheetahs left in the wild, biologists think that their numbers were much lower at some time in the past because cheetah populations have very little genetic variation. What is the most likely reason for the lack of genetic variability in cheetahs?
A) Environmental stochasticity
B) Demographic stochasticity
C) Genetic stochasticity
D) Genetic drift

Accepted Answer

Genetic drift is a mechanism of evolution that leads to a change in the genetic makeup of a population due to random events. It is most pronounced in small populations and can lead to a reduction in genetic variation, which is likely what happened to cheetahs in the past.

Question 19

Which of the following could be considered the opposite of the density dependence seen in the standard logistic equation?
A) Genetic drift
B) An Allee effect
C) Environmental stochasticity
D) Delayed density dependence

Accepted Answer

An Allee effect is considered the opposite of density dependence because it describes a situation where population growth is positively correlated with population size, meaning that populations may struggle to grow when they are too small, unlike the logistic model where growth slows as population size increases.

Question 20

Which of the following would be least likely to cause the extinction of a population comprising 20 individuals within a single generation?
A) A natural catastrophe
B) Environmental stochasticity
C) Demographic stochasticity
D) Allee effects

Accepted Answer

The answer of Which of the following would be least...

Quiz 10: Population Dynamics

Refer to the figure. Based on the data in the figure, what is the carrying capacity in this environment?

Which of the following is most likely to lead to population cycles?

In the 1950s, Nicholson's experiments with blowflies showed that delayed density dependence can produce population cycles. If the experimental subjects in these studies had been blowflies with somewhat lower growth rates, he most likely would have observed which pattern of population dynamics?

Nicholson (1957) found that when adult sheep blowfly populations are high, egg production by blowflies

Which statement about Nicholson's experiments with blowflies is true?

Assuming that their average population growth rates and all other factors are equal, which population would most likely be at risk for extinction?

Which of the following statements about effective population size is true?

Which of the following statements is a conclusion of Jones and Diamond's studies of extinction in bird populations in the Channel Islands?

Suppose that only two females and a small number of males are left in a population of a highly endangered bird. Although all of these birds are healthy, by chance, both females fail to reproduce and the population goes extinct. This extinction is best described as a consequence of

At low population densities, the flocking behavior of some species of birds is disrupted to the extent that the population growth rate is lower at very low densities than it is at somewhat higher densities. This is an example of

Refer to the figure. The figure is derived from studies of the populations and per-individual growth rates of three species of rodents in the U.S. desert southwest. According to the figure, which population(s) show(s) evidence of Allee effects?

Which statement about genetic drift is false?

Refer to the figure. Based on the figure, extinction was a possible outcome for _______ breeding pairs.

Imagine a moose in Grand Teton National Park, Wyoming is wandering around in a field of flowers. As it walks, it crushes and kills several flowers that turn out to be the last of their kind, causing that species of flower to go extinct. What is this an example of?

Although there are approximately 10,000 cheetahs left in the wild, biologists think that their numbers were much lower at some time in the past because cheetah populations have very little genetic variation. What is the most likely reason for the lack of genetic variability in cheetahs?

Which of the following could be considered the opposite of the density dependence seen in the standard logistic equation?

Which of the following would be least likely to cause the extinction of a population comprising 20 individuals within a single generation?