Question 1

Which of the following best describes the concept of an organism's ecological niche as formalized by G.E. Hutchinson?

Accepted Answer

An n-dimensional hypervolume that defines the range of environmental conditions and resources within which a species can survive, grow, and reproduce.

Question 2

A plant species can survive, grow, and reproduce at temperatures between 10°C and 30°C, humidity between 20% and 60%, and nitrogen concentrations between 5 and 15 mg/L. What does this range of conditions represent?

Accepted Answer

The plant's fundamental niche.

Question 3

Which of the following scenarios would most likely result in exponential population growth?

Accepted Answer

A population of bacteria introduced to a new, nutrient-rich petri dish.

Question 4

Which equation correctly represents the rate of change in population size under exponential growth?

Accepted Answer

$$\frac{dN}{dt} = rN$$

Question 5

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

Accepted Answer

The growth rate decreases.

Question 6

Which of the following best describes the difference between a fundamental niche and a realized niche?

Accepted Answer

A fundamental niche is the range of conditions a species could potentially occupy, while a realized niche is the range it actually occupies due to biotic interactions.

Question 7

A population of barnacles is limited in its lower tidal range by competition with another barnacle species, but can survive across a wider range if the competitor is removed. What does the wider range represent?

Accepted Answer

The fundamental niche of the barnacle.

Question 8

For a population experiencing exponential growth, the per capita growth rate ($$r) _____ $$over time while the overall rate of population growth ($$\frac{dN}{dt}) ______ $$over time.

Accepted Answer

Stays the same; increases

Question 9

Which of the following is an example of a density-independent factor affecting population growth?

Accepted Answer

A severe drought

Question 10

The carrying capacity ($$K) of a $$population is best defined as:

Accepted Answer

The maximum number of individuals that can be supported in a particular habitat over a sustained period of time.

Question 11

A population of Hawaiian honeycreepers can live in forests at elevations from 1,000–3,500 m, but after the introduction of avian malaria (which occurs below 1,900 m), they are only found between 2,000–3,500 m. This area represents their _______ niche, and their distribution is constrained by _______.

Accepted Answer

Realized; biotic factors

Question 12

Which of the following equations represents the logistic growth model?

Accepted Answer

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

Question 13

Which of the following populations is most likely to demonstrate an exponential growth curve?

Accepted Answer

A population of an invasive grass species colonizing a new habitat.

Question 14

If a population's birth rate plus immigration rate is less than its death rate plus emigration rate, what will happen to the population size?

Accepted Answer

The population will decline.

Question 15

Which of the following best explains why the realized niche of a species is often smaller than its fundamental niche?

Accepted Answer

Biotic interactions such as competition and predation restrict the realized niche.

Question 16

In the context of population ecology, what does the variable $$N$$ represent in the equations $$\frac{dN}{dt} = rN$$ and $$\frac{dN}{dt} = rN \left(1 - \frac{N}{K}\right)$$?

Accepted Answer

The population size.

Question 17

Which of the following is a scenario where logistic growth is most likely to occur?

Accepted Answer

A population of deer in a forest where food and space become limited as the population grows.

Question 18

Which of the following statements about carrying capacity ($$K) is $$TRUE?

Accepted Answer

Carrying capacity can change over time as resources in the environment change.

Question 19

If a population is at its carrying capacity ($$N = K$$), what is the expected value of $$\frac{dN}{dt} in $$the logistic growth equation?

Accepted Answer

$$\frac{dN}{dt} = 0$$

Niche Concept and Population Ecology: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards