Q: A population of flour beetles has a per capita growth rate ($$r) of 0.10. If $$the initial population size ($$N_0) is 100$$, what will the population size be after 1 generation, assuming exponential growth?

$$N = N_0$ e$$^{rt}$$ = 100 e$$^{0.10 \times 1}$$ \approx 110.5$$

Question 1

Which equation best describes exponential population growth, and what does each variable represent?

Accepted Answer

$$ \frac{dN}{dt} = rN $$ ; where $$N is $$population size, $$r is $$per capita growth rate, and $$t is $$time.

Question 2

A population of flour beetles has a per capita growth rate ($$r) of 0.10. If $$the initial population size ($$N_0) is 100$$, what will the population size be after 1 generation, assuming exponential growth?

Accepted Answer

$$N = N_0$ e$$^{rt}$$ = 100 e$$^{0.10 	imes 1}$$ \approx 110.5$$

Question 3

Which of the following best explains why populations cannot grow indefinitely?

Accepted Answer

Resource limitations and environmental resistance eventually slow growth, leading to a carrying capacity ($$K).$$

Question 4

What is carrying capacity ($$K) $$and how does it affect population growth?

Accepted Answer

Carrying capacity ($$K) is $$the maximum population size an environment can sustain; as $$N$$ approaches $$K$$, growth rate slows and eventually stops.

Question 5

Which factor is density-dependent and can limit population size?

Accepted Answer

Competition for resources

Question 6

A catastrophic oil spill causes a sudden decline in a seabird population. This is an example of which type of limiting factor?

Accepted Answer

Density-independent factor

Question 7

In the reindeer case study, what was the primary cause of the population crash after 42 years?

Accepted Answer

Over-foraging of the food supply led to a decline in carrying capacity and population crash.

Question 8

Which equation models logistic population growth, incorporating carrying capacity ($$K$$)?

Accepted Answer

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

Question 9

Why does fecundity (clutch size) of sparrows decline at high population density?

Accepted Answer

Increased competition for resources at high density reduces available energy for reproduction.

Question 10

In a field experiment on hare populations, which treatment resulted in the highest survival rate?

Accepted Answer

No lynx & extra food

Question 11

What is a metapopulation?

Accepted Answer

A population of populations, where subpopulations may go extinct but can be restored by migration.

Question 12

Which statement best describes the 'rescue effect' in metapopulation dynamics?

Accepted Answer

Migration from source populations can restore or establish subpopulations in sink habitats.

Question 13

If a population overshoots its carrying capacity ($$K$$), what is the most likely outcome?

Accepted Answer

A die-off event may occur, and carrying capacity itself may decline due to resource depletion.

Question 14

Which hypothesis explains population cycles in the lynx-hare system as being primarily driven by food availability?

Accepted Answer

Bottom-up hypothesis

Question 15

What is the main difference between source and sink habitats in metapopulation theory?

Accepted Answer

Source habitats have high quality and produce excess individuals; sink habitats are low quality and rely on immigrants.

Question 16

Which factor is most likely to reduce genetic exchange among populations?

Accepted Answer

Habitat fragmentation

Question 17

A population of Paramecium aurelia is grown in two conditions: high food supply ($$K=195) $$and low food supply ($$K=105). $$What does this experiment demonstrate about carrying capacity?

Accepted Answer

Carrying capacity ($$K) is $$not fixed and depends on resource availability.

Question 18

Which scenario best illustrates a density-independent factor affecting population size?

Accepted Answer

A hurricane destroys a coastal bird population regardless of its density.

Question 19

Which of the following is a multi-step problem: Calculate the population size after 3 generations for a population of E. coli with $$r=59$$ and $$N_0=1$, assuming exponential growth. Use N$$ = $$N_0$$ $$e^{rt}.$$

Accepted Answer

$$N = 1 	imes e$$^{59 	imes 3}$$ \approx 1 	imes e$$^{177}$$  ($$which is an extremely large number)

Population Ecology: Growth, Regulation, and Metapopulation Dynamics

Study Guide - Practice Questions

Study Guide - Flashcards