Q: A population of rabbits has a per capita growth rate $$r = 0.5. If $$the initial population size is $$N_0 = 100$, what will the population size be after one generation, assuming exponential growth and no limiting factors? Use the exponential growth equation: N_t$$ = $$N_0$$ $$e^{rt}$$, where $$t = 1.$$

$$N_1 = 100$$ \times $$e^{0.5}$$ \approx 164$$

Question 1

Which of the following best describes the difference between exponential and logistic population growth?

Accepted Answer

Exponential growth is density-independent and results in a J-shaped curve, while logistic growth is density-dependent and results in an S-shaped curve.

Question 2

A population of rabbits has a per capita growth rate $$r = 0.5. If $$the initial population size is $$N_0 = 100$, what will the population size be after one generation, assuming exponential growth and no limiting factors? Use the exponential growth equation: N_t$$ = $$N_0$$ $$e^{rt}$$, where $$t = 1.$$

Accepted Answer

$$N_1 = 100$$ 	imes $$e^{0.5}$$ \approx 164$$

Question 3

Which of the following is an example of a density-independent factor that can limit population size?

Accepted Answer

A severe drought

Question 4

A researcher observes that a species of bird lays fewer eggs per clutch in years with scarce food, but more eggs when food is abundant. This is an example of which concept?

Accepted Answer

Fitness trade-off between fecundity and resource availability

Question 5

Which of the following best describes a keystone species?

Accepted Answer

A species whose removal causes a dramatic shift in community structure and function

Question 6

Which of the following scenarios best illustrates the concept of biomagnification?

Accepted Answer

A toxic chemical accumulates in higher concentrations in organisms at higher trophic levels, such as DDT in birds of prey.

Question 7

Which of the following is NOT a property of a population as defined in ecology?

Accepted Answer

Abiotic constraints

Question 8

In the nitrogen cycle, which process is primarily responsible for converting atmospheric nitrogen ($$N_2) $$into a form usable by plants?

Accepted Answer

Nitrogen fixation

Question 9

Which of the following best explains why the phosphorus cycle is considered a local rather than a global cycle?

Accepted Answer

Phosphorus does not have a significant gaseous phase in the atmosphere.

Question 10

A population of deer is experiencing the extinction vortex. Which of the following sequences best describes this process?

Accepted Answer

Reduced genetic diversity → lower offspring viability → smaller population → further loss of genetic diversity

Question 11

Which of the following is a real-world example of regulation resulting in environmental success?

Accepted Answer

The banning of DDT in the US leading to the recovery of bird populations

Question 12

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

Accepted Answer

A fundamental niche is the full range of environmental conditions an organism can use, while a realized niche is the range it actually uses due to competition and other biotic factors.

Question 13

Which of the following is a characteristic of a Type III survivorship curve?

Accepted Answer

High juvenile mortality with few individuals surviving to adulthood

Question 14

Which of the following best explains why food chains are typically short?

Accepted Answer

Energy is lost at each trophic level, with only about 10% transferred to the next level.

Question 15

Which of the following is an example of a provisioning service provided by biodiversity?

Accepted Answer

Production of food, such as fish and crops

Question 16

Which of the following best describes the effect of a rain shadow on local climate?

Accepted Answer

It causes dry conditions on the leeward side of a mountain due to descending, warming air.

Question 17

Which of the following actions can individuals take to help conserve biodiversity?

Accepted Answer

Participating in citizen science projects

Question 18

Which of the following best explains why tallgrass prairies in Iowa are endangered?

Accepted Answer

They have been largely converted to agriculture and suffer from woody encroachment due to lack of fire and large herbivores.

Question 19

Which of the following is a consequence of nutrient loading in aquatic ecosystems, such as the Gulf of Mexico dead zone?

Accepted Answer

Hypoxia (low oxygen) leading to fish kills and loss of biodiversity

Question 20

Which of the following is a correct statement about the relationship between latitude and biodiversity?

Accepted Answer

Biodiversity is generally higher at lower latitudes (closer to the equator).

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