Q: Researchers use the mark-recapture method to estimate a fish population. They mark 120 fish, release them, and later capture 80 fish, 20 of which are marked. What is the estimated population size ($$N$$)?

$$N = \frac{120 \times 80}{20} = 480$$

Q: If a population of beetles has a per capita rate of increase $$r = 0.2$$ and an initial population size $$N_0 = 100$, what will the population size be after 5 generations, assuming exponential growth? Use N_t$$ = $$N_0$$ $$e^{rt}.$$

$$N_5 = 100$$ $$e^{0.2 \times 5} = 100$$ $$e^{1}$$ \approx 271.8$$

Q: A population of 200 penguins is marked. Later, 100 penguins are captured, 25 of which are marked. What is the estimated population size ($$N$$)?

$$N = \frac{200 \times 100}{25} = 800$$

Question 1

Which of the following best describes 'population density' in population ecology?

Accepted Answer

The number of individuals per unit area or volume.

Question 2

A population of 500 deer has 25 births and 10 deaths in one year. What is the per capita rate of increase ($$r) $$for this population?

Accepted Answer

$$r = \frac{25-10}{500} = 0.03$$

Question 3

Which pattern of dispersion is most likely to result from territorial behavior among individuals?

Accepted Answer

Uniform dispersion

Question 4

Researchers use the mark-recapture method to estimate a fish population. They mark 120 fish, release them, and later capture 80 fish, 20 of which are marked. What is the estimated population size ($$N$$)?

Accepted Answer

$$N = \frac{120 	imes 80}{20} = 480$$

Question 5

Which survivorship curve type is characterized by high mortality in young individuals and low mortality in survivors?

Accepted Answer

Type III

Question 6

If a population of beetles has a per capita rate of increase $$r = 0.2$$ and an initial population size $$N_0 = 100$, what will the population size be after 5 generations, assuming exponential growth? Use N_t$$ = $$N_0$$ $$e^{rt}.$$

Accepted Answer

$$N_5 = 100$$ $$e^{0.2 	imes 5} = 100$$ $$e^{1}$$ \approx 271.8$$

Question 7

Which of the following is NOT a density-dependent factor affecting population growth?

Accepted Answer

Earthquake

Question 8

A population of rabbits doubles every 4 months. What is the per capita rate of increase ($$r$$)?

Accepted Answer

$$r = \frac{\ln(2)}{4} \approx 0.173$$

Question 9

Which life history strategy is most likely favored in unpredictable environments?

Accepted Answer

Semelparity

Question 10

In the logistic growth model, what happens to the population growth rate as the population size ($$N) $$approaches the carrying capacity ($$K$$)?

Accepted Answer

Growth rate decreases and approaches zero

Question 11

Which equation correctly represents the logistic growth rate of a population?

Accepted Answer

$$\frac{dN}{dt} = rN \left(1 - \frac{N}{K}\right)$$

Question 12

A population of 200 penguins is marked. Later, 100 penguins are captured, 25 of which are marked. What is the estimated population size ($$N$$)?

Accepted Answer

$$N = \frac{200 	imes 100}{25} = 800$$

Question 13

Which of the following best describes a 'cohort' in demographic studies?

Accepted Answer

A group of individuals of the same age followed through time.

Question 14

If the net reproductive rate ($$R_0) of a $$population is less than 1, what does this indicate about the population?

Accepted Answer

The population is decreasing in size.

Question 15

Which of the following is a real-world example of a density-independent factor affecting population size?

Accepted Answer

A drought causing mass mortality in a plant population.

Question 16

A population of 1,000 individuals has an annual per capita birth rate $$b = 0.04$$ and death rate $$m = 0.03. $$What is the expected change in population size ($$\Delta N) $$over one year?

Accepted Answer

$$\Delta N = (b - m)N = (0.04 - 0.03) 	imes 1000 = 10$$

Question 17

Which of the following statements about exponential growth is correct?

Accepted Answer

Exponential growth occurs when resources are unlimited and population size increases at a constant rate.

Question 18

Which of the following is a likely consequence of a population overshooting its carrying capacity ($$K$$)?

Accepted Answer

Population size may decline due to resource depletion.

Question 19

In a predator-prey cycle, what typically happens after the prey population increases?

Accepted Answer

Predator population increases, followed by a decrease in prey population.

Population Ecology: Principles and Patterns

Study Guide - Practice Questions

Study Guide - Flashcards