Q: Which of the following equations accurately represents the change in population size ($$\Delta N) $$over time?

$$\Delta N = (\text{Births} + \text{Immigrants}) - (\text{Deaths} + \text{Emigrants})$$

Question 1

Which of the following best describes the difference between an organism's environment, habitat, and niche?

Accepted Answer

Environment is the total sum of all external biotic and abiotic factors, habitat is the specific location where an organism lives and reproduces, and niche is the ecological role a species performs in its habitat.

Question 2

Which of the following is an example of a biotic factor influencing an ecosystem?

Accepted Answer

The density of trees in a forest.

Question 3

A researcher is studying how the distribution of capybaras is affected by the presence of caiman predators in a wetland. At which level of ecological study is this research focused?

Accepted Answer

Community ecology

Question 4

Which of the following scenarios best illustrates the concept of a species' niche?

Accepted Answer

A bee pollinating flowers in a meadow.

Question 5

Which of the following equations accurately represents the change in population size ($$\Delta N) $$over time?

Accepted Answer

$$\Delta N = (	ext{Births} + 	ext{Immigrants}) - (	ext{Deaths} + 	ext{Emigrants})$$

Question 6

Suppose a population of rabbits in a forest has an initial population of 500. Over the course of one year, 200 new rabbits are born, 150 rabbits die, 20 rabbits emigrate, and 50 rabbits immigrate. What is the population size at the end of the year?

Accepted Answer

580 rabbits

Question 7

Which of the following is a density-independent factor that limits a population’s growth?

Accepted Answer

Drought

Question 8

A population of 200 fish in an isolated pond experiences a per capita birth rate ($$b) of 0.3 $$and a per capita death rate ($$d) of 0.1 in a $$month. What is the intrinsic rate of increase ($$r) $$and the population growth rate ($$\Delta N$$)?

Accepted Answer

$$r = 0.2$$, $$\Delta N = 40$$

Question 9

If a bacterial population starts with 100 cells and has a per capita population growth rate $$r = 0.1$$ cells per hour per cell, what would be the population size after 5 hours? (Use $$N_t = N_0$ e$$^{rt}$$)

Accepted Answer

165 individuals

Question 10

Which of the following statements about r- and K-selection is true?

Accepted Answer

K-selected organisms tend to exhibit iteroparity so they can better care for their offspring.

Question 11

Which of the following is an example of character displacement?

Accepted Answer

Two sympatric species of finches evolve different beak sizes to reduce competition for seeds.

Question 12

Which of the following best describes the relationship between a harmless species mimicking a harmful one?

Accepted Answer

Batesian mimicry

Question 13

Which of the following is NOT an example of exploitation?

Accepted Answer

These are all examples of exploitation.

Question 14

If a forest contains 47,000 kg of plant material, how many kg of tertiary consumers can it support, assuming 10% energy transfer between trophic levels?

Accepted Answer

47 kg

Question 15

Which of the following best explains why moderate levels of disturbance foster the highest diversity in a community?

Accepted Answer

All of the above.

Question 16

Which of the following communities would likely have the highest species diversity?

Accepted Answer

A large island in the tropics.

Question 17

According to the Island Equilibrium Model, which type of island would likely have the highest extinction rate?

Accepted Answer

An island that is small and far from the mainland.

Ecology and Population Biology: Structured Study Notes

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