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 time unit, assuming exponential growth and no limiting factors?

$$N = N_0$ \times e$$^{rt}$$ = 100 \times e$$^{0.5 \times 1}$$ \approx 164$$

Question 1

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

Accepted Answer

Exponential growth occurs when resources are unlimited, resulting in a J-shaped curve, while logistic growth incorporates carrying capacity ($$K) $$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 time unit, assuming exponential growth and no limiting factors?

Accepted Answer

$$N = N_0$ 	imes e$$^{rt}$$ = 100 	imes e$$^{0.5 	imes 1}$$ \approx 164$$

Question 3

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

Accepted Answer

A drought causing a reduction in available water for all individuals regardless of population size.

Question 4

Which survivorship curve (Type I, II, or III) best describes a population where most individuals survive to old age, but mortality increases rapidly in later life?

Accepted Answer

Type I

Question 5

A researcher observes that two bird species occupy the same forest but feed at different heights in the trees. This is an example of:

Accepted Answer

Resource partitioning leading to realized niches

Question 6

Which of the following best explains why food chains are typically short, rarely exceeding four or five trophic levels?

Accepted Answer

Energy transfer between trophic levels is inefficient, with only about 10% of energy passed on to the next level.

Question 7

Which of the following is a consequence of biomagnification in aquatic food webs?

Accepted Answer

Top predators accumulate the highest concentrations of persistent toxins.

Question 8

Which of the following is NOT a major threat to biodiversity as identified in conservation biology?

Accepted Answer

Natural selection

Question 9

Which of the following best describes the role of a keystone species in an ecosystem?

Accepted Answer

A species whose impact on its community is disproportionately large relative to its abundance.

Question 10

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 11

Which process in the nitrogen cycle is primarily responsible for converting atmospheric $$N_2$$ into a form usable by plants?

Accepted Answer

Nitrogen fixation

Question 12

Why is the phosphorus cycle considered a local rather than a global cycle?

Accepted Answer

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

Question 13

Which of the following best describes the concept of ecological footprint?

Accepted Answer

The total area of land and water required to produce the resources a person or population consumes and to absorb the wastes they generate.

Question 14

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

Accepted Answer

Reduced genetic diversity $$\rightarrow$$ lower offspring viability $$\rightarrow$$ smaller population $$\rightarrow$$ further loss of genetic diversity

Question 15

Which of the following is a strategy to reduce one’s carbon footprint?

Accepted Answer

Using public transportation instead of driving alone.

Question 16

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

Accepted Answer

Over 99% have been converted to agriculture and lack of fire and large herbivores has led to woody encroachment.

Question 17

Which of the following is an example of Batesian mimicry?

Accepted Answer

A harmless king snake resembling a venomous coral snake.

Question 18

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 a species can use, while a realized niche is the portion actually occupied due to competition and other biotic factors.

Question 19

Which of the following is a density-dependent factor that can limit population growth?

Accepted Answer

Competition for resources

Question 20

Which of the following best describes the process of primary succession?

Accepted Answer

The colonization of a barren landscape, such as after a volcanic eruption, where soil has not yet formed.

Ecology, Ecosystems, and Biodiversity: Study Notes

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