AP Environmental Science Unit 3 Practice Test: Populations (2024)

Question 1

Question 1 Explanation:

The correct answer is (B). The species richness of a community is influenced by latitude, time, habitat size, and distance from other communities. Survivorship curves are NOT a factor that affects species richness. Survivorship curves are graphs that represent the proportion of surviving individuals as the cohort ages.

Question 2

Question 2 Explanation:

The correct answer is (C). The competitive exclusion principle states that two species competing for the same limiting resource(s) cannot coexist. One of two species sharing identical, or nearly identical, niches will be driven to local extinction.

Question 3

Question 3 Explanation:

Question 4

Question 4 Explanation:

The correct answer is (C). The logistic growth model produces an S-shaped curve when graphed. This model illustrates a population that initially grows exponentially (curves sharply upward), slows (curves slowly to the right) as the population approaches the carrying capacity of the environment, and then levels off at carrying capacity.

Question 5

Question 5 Explanation:

The correct answer is (B). R-adapted species have adapted for high rates of growth. They are usually smaller in size, require little energy, produce many offspring, exhibit an early maturity and a short lifespan, and see most individuals die within a short period of time (though some individuals live for an extended period of time). K-adapted species have slower growth, are usually much larger, live longer lives, and have adapted to live at or near carrying capacity. Of the choices, mice most closely match the r-adapted species description.

Question 6

Question 6 Explanation:

The correct answer is (D). Within a population, there are individuals of varying ages. When population ecologists describe the number of individuals fitting into a particular age category, they are looking at population age structure. This data helps ecologists understand how quickly a population can grow.

Question 7

Questions 7-9 refer to the following graphs:

Which example fits the growth pattern shown in Graph II?

Question 7 Explanation:

The correct answer is (C). Graph II shows a growing population with a sudden drop, indicating that the population grew exponentially and then saw a dramatic decline. This can be caused by the organism running out of food, causing mass starvation and death. Thus, the reindeer example is the best choice.

Question 8

Which letter on the graphs represents a population’s carrying capacity?

Question 8 Explanation:

The correct answer is (B). When a population reaches carrying capacity, it stops growing and becomes stable.

Question 9

Which letter on the graph represents exponential growth?

Question 9 Explanation:

The correct answer is (D). Exponential growth appears as a J-shaped curve on a graph.

Question 10

Question 10 Explanation:

The correct answer is (C). Demographers calculate replacement level fertility to determine changes in population size. Replacement level fertility looks at the average number of offspring needed to offset the average number of deaths in a population. Typically, for a population of humans, this requires a bit over 2 offspring per woman.

Question 11

Question 11 refers to the following graph:

During which phase(s) of the demographic transition does the death rate decline while the birth rate remains high, causing the population to grow rapidly?

Question 11 Explanation:

The correct answer is (B). In Phase 2, both the birth rate line and the death rate line are declining while the population size line is increasing.

Question 12

Question 12 refers to the following age structure diagram:

A country with an age structure like the one shown above will experience:

Question 12 Explanation:

The correct answer is (C). A country with an age structure diagram like the one above will experience a decline in the population because there are fewer children than adults. Therefore, when the children reach childbearing age, it is unlikely they will collectively produce enough offspring to offset their elderly, dying parents.

Question 13

Question 13 Explanation:

The correct answer is (B). Conversion of forested areas into agricultural land reduces the uptake of carbon dioxide by plants, thereby not removing carbon dioxide from the atmosphere and contributing to global warming.

Question 14

Which line on the chart CORRECTLY matches the traits for K-selected and r-selected species?

Question 14 Explanation:

Question 15

Question 15 Explanation:

The correct answer is (D). Generalists can survive in a wide range of ecosystems and survive on a large variety of food sources.

Question 16

Question 16 Explanation:

The correct answer is (D). Density-dependent factors include things such as disease, where a larger population makes it easier for the disease to spread from one member to the next.

Question 17

Question 17 Explanation:

The correct answer is (D). An age structure diagram displays the relative percent of a population at each age category. In a country with a high birth rate and a high death rate, the base of the pyramid, reflecting youth, would be widest, and there would be a steep rise to the top of the pyramid as more people die at a young age due to lack of healthcare and poor living conditions.

Question 18

Question 18 Explanation:

The correct answer is (A). A country in phase four of the demographic transition model would likely show a slowly declining rate of population growth and more affluent populations tend to have more women going to college and entering the workforce.

Question 19

Type I survivorship curves show that the number of survivors remains stable early but eventually decreases sharply at a particular upper age limit. Type II survivorship curves show that the number of survivors steadily decreases with an increase in age.

Which of the following can you determine from the descriptions of survivorship curves provided above?

Question 19 Explanation:

The correct answer is (D). In a Type II survivorship curve, species typically have a middle-sized number of offspring that receive some parental care and thus have an increased chance of surviving to adulthood, but some factor, such as predation, leads to a steady decline in survivorship.

Question 20

Which of the following factors lead(s) to a declining birth rate in countries transitioning from phase two to phase three in the demographic transition model?

I. More women tend to stay home as a country becomes more developed, leading to decreased birth rates

II.More women tend to earn advanced degrees in developed nations, so they enter the workforce and have less time to raise children

III.There are more opportunities to own businesses in developed nations

Question 20 Explanation:

The correct answer is (D). Developing nations tend to recognize the economic potential of women and their equality with men. As more women attain higher education and start their businesses, less time is devoted to having children.