Question 1

Which of the following best describes the concept of carrying capacity ($$K) in $$population ecology?

Accepted Answer

The maximum number of individuals that can be supported indefinitely by the available resources in a habitat.

Question 2

A population of reindeer was artificially introduced to an island with abundant resources. After a rapid increase, the population crashed. What is the most likely explanation for this pattern?

Accepted Answer

The population overshot the carrying capacity ($$K$$), depleting resources and causing a crash.

Question 3

Which equation best represents logistic population growth, where $$N is $$population size, $$r is $$intrinsic growth rate, and $$K is $$carrying capacity?

Accepted Answer

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

Question 4

In the predator-prey cycle between lynx and hare, what is the primary reason for the lag in lynx population changes compared to hare population changes?

Accepted Answer

Lynx population growth depends on the availability of hares as food, so changes in hare numbers precede changes in lynx numbers.

Question 5

Which of the following is an example of a density-dependent factor that limits population growth?

Accepted Answer

Accumulation of toxic wastes such as ammonia in fruit fly larvae cultures.

Question 6

If two species compete for the same limited resource and one is a much better competitor, what is the most likely long-term outcome?

Accepted Answer

The weaker competitor will be excluded from the resource and may go extinct locally (competitive exclusion).

Question 7

Which of the following best defines a species' fundamental niche?

Accepted Answer

The full range of resources a species can use and conditions it can tolerate in the absence of competitors.

Question 8

What is the difference between mutualism and commensalism?

Accepted Answer

Mutualism increases the fitness of both species, while commensalism benefits one species and has no effect on the other.

Question 9

After the reintroduction of wolves to Yellowstone National Park, which ecological phenomenon was observed?

Accepted Answer

A trophic cascade, where changes in wolf population affected multiple other species and ecosystem processes.

Question 10

Which of the following scenarios best illustrates resource partitioning?

Accepted Answer

Two bird species feed on seeds of different sizes, reducing competition.

Question 11

Which population growth model is most appropriate for a population experiencing limited resources and competition?

Accepted Answer

Logistic growth model

Question 12

If a population is growing according to the exponential model, which equation describes its growth?

Accepted Answer

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

Question 13

Which of the following is a plausible outcome when two species have partially overlapping niches?

Accepted Answer

The weaker competitor shifts to a realized niche, using fewer resources.

Question 14

Which factor is most likely to be density-independent in its effect on population growth?

Accepted Answer

A severe drought reducing water availability.

Question 15

In a community, what is the effect of a keystone species?

Accepted Answer

It has a disproportionately large effect on community structure and ecosystem function.

Question 16

Which of the following best describes competitive exclusion?

Accepted Answer

When two species compete for the same limiting resource, one will outcompete and exclude the other from the habitat.

Question 17

A population of fruit flies in a laboratory is limited by ammonia buildup from their feces. What type of population regulation is this?

Accepted Answer

Density-dependent regulation

Question 18

Which of the following interactions is classified as a - / - interaction?

Accepted Answer

Competition

Question 19

Which of the following would most likely increase the resilience of a biological community?

Accepted Answer

High species richness and evenness

Question 20

If human population growth rate ($$r) $$becomes negative, what will happen to the population size over time?

Accepted Answer

The population size will decrease.

Population Ecology and Community Interactions: Density Dependence, Competition, and Ecological Niches

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