---
title: "AP Environmental Science Unit 3 Practice Test"
description: "A timed AP Environmental Science Unit 3 (Populations) practice test in the AP format, drawn from 2,465 multiple-choice questions and 42 FRQs written for the unit. The standard version takes about 70 minutes."
canonical: "https://fiveable.me/ap-enviro/unit-test/3"
type: "unit-test"
subject: "AP Environmental Science"
unit: "Unit 3"
---

# AP Environmental Science Unit 3 Practice Test

## Overview

A timed AP Environmental Science Unit 3 (Populations) practice test in the AP format, drawn from 2,465 multiple-choice questions and 42 FRQs written for the unit. The standard version takes about 70 minutes.

## Test Format

- 20 Multiple Choice Questions (23 minutes)
- 1 FRQ – FRQ 1 – Design an Investigation (23 minutes)
- 1 FRQ – FRQ 2 – Analyze and Interpret Quantitative Data (23 minutes)

## Unit FRQs by Type

- [FRQ 1 – Design an Investigation](/ap-enviro/frqs/design-an-investigation?unit=3): 16 questions
- [FRQ 2 – Analyze and Interpret Quantitative Data](/ap-enviro/frqs/data-analysis?unit=3): 13 questions
- [FRQ 3 – Analyze an Environmental Problem Doing Calculations](/ap-enviro/frqs/calculations?unit=3): 13 questions

## Practice Questions

### Question 1

Deforestation fragments a tropical rainforest into patches separated by agriculture. Harpy eagles that hunt canopy mammals and need large continuous territories vanish within five years, while coyotes establish populations in agricultural zones. Which explanation best accounts for their different responses to fragmentation?

- (A) Harpy eagles are habitat specialists and coyotes are generalist resource exploiters.
- (B) Harpy eagles need more food energy than coyotes because of larger body size.
- (C) Harpy eagles reproduce more slowly than coyotes, limiting recolonization of patches.
- (D) Differences in visual acuity determine predator success across open versus forest habitats.

**Answer: (A)** Specialist habitat and prey requirements make harpy eagles vulnerable when forests fragment. Coyotes' broad diet and habitat tolerance let them use agricultural mosaics and persist.

### Question 2

A park restricts human access to a remote alpine meadow to protect a specialist plant with a narrow elevation range. Average temperatures rise by 2°C. Which outcome is an unintended consequence of this protection strategy?

- (A) The plant cannot find higher suitable habitat and declines despite protection.
- (B) The plant will rapidly evolve tolerance to warmer temperatures and expand.
- (C) The specialist will outcompete generalists moving upslope as conditions change.
- (D) Restricting human access eliminates all environmental stress on the plant.

**Answer: (A)** Specialist species have narrow niches and cannot track warming if suitable higher habitat is limited. Mountains have finite elevation so protection from human disturbance cannot prevent range loss.

### Question 3

River otter populations have declined in many regions where rivers have been dammed and polluted, while populations of generalist predators like raccoons have remained stable or increased. Which of the following best explains this difference in population responses?

- (A) The river otter's specialization on fish and freshwater habitats means it requires clean, flowing water with adequate fish populations; when rivers are dammed or polluted, otter populations decline because they cannot switch to alternative prey or habitats like generalist predators can.
- (B) The river otter's territorial behavior and specialization on fish and freshwater habitats means it requires large, exclusive home ranges along rivers; when rivers are dammed or polluted, otter populations decline because their territorial requirements prevent them from adapting to smaller habitat patches like generalist predators can.
- (C) The river otter's specialization on fish and freshwater habitats means it requires clean, flowing water with adequate fish populations; when rivers are dammed or polluted, otter populations initially decline but then recover as otters adapt their foraging strategies, unlike generalist predators that maintain stable populations throughout.
- (D) The river otter's specialization on fish and freshwater habitats means it requires clean, flowing water with adequate fish populations; when rivers are dammed or polluted, otter populations decline primarily because generalist predators increase in number and outcompete otters for limited fish resources.

**Answer: (A)** Linking dietary and habitat specialization to vulnerability during environmental degradation reveals the mechanism of specialist disadvantage. River otters' dependence on specific prey (fish) and habitat conditions (clean, flowing water) creates inflexibility when those conditions deteriorate, whereas generalists like raccoons can exploit alternative food sources and tolerate degraded habitats—this directly demonstrates the EK principle that specialists are disadvantaged when habitats change.

### Question 4

Invasive coyotes have successfully colonized ecosystems across North America, from deserts to forests to urban areas, often displacing native specialist predators. Which of the following best explains why coyotes succeed as invasive species while native specialists cannot compete with them?

- (A) Invasive species like coyotes succeed in colonizing new ecosystems because their generalist diet (small mammals, insects, vegetation, carrion) and high environmental tolerance allow them to exploit diverse resources, whereas native specialists dependent on specific prey or habitat conditions are outcompeted or displaced.
- (B) Invasive species like coyotes succeed in colonizing new ecosystems because they lack natural predators in their new ranges, allowing them to exploit diverse resources without population control, whereas native specialists dependent on specific prey or habitat conditions are outcompeted or displaced.
- (C) Invasive species like coyotes with generalist diets (small mammals, insects, vegetation, carrion) and high environmental tolerance can exploit diverse resources, allowing them to coexist with native specialists dependent on specific prey or habitat conditions through resource partitioning.
- (D) Invasive species like coyotes succeed in colonizing stable, undisturbed ecosystems because their generalist diet (small mammals, insects, vegetation, carrion) and high environmental tolerance allow them to exploit diverse resources, whereas native specialists dependent on specific prey or habitat conditions are outcompeted or displaced.

**Answer: (A)** Connecting generalist dietary and environmental flexibility to invasive success reveals the mechanism of competitive advantage. Coyotes' ability to consume diverse food sources and tolerate varied conditions enables them to establish in any ecosystem, whereas native specialists with narrow requirements cannot compete—this directly demonstrates the EK principle that generalists are advantaged in changing, heterogeneous environments like those created by invasion and ecosystem disruption.

### Question 5

Koala numbers drop when eucalyptus forests are cleared. Why can't koalas persist while generalist herbivores like deer do in the same areas?

- (A) Koalas specialize on eucalyptus and cannot switch to other plants.
- (B) Mistakenly identifies the giant panda as a dietary generalist.
- (C) Attributes decline to body size or density rather than dietary inflexibility.
- (D) Claims specialization protects koalas from competition and ensures survival.

**Answer: (A)** Koalas depend almost exclusively on eucalyptus and lack the digestive flexibility to use other plants. Generalist herbivores can eat many species or move, allowing them to persist after habitat change.

### Question 6

Urban areas offer variable food, fluctuating temperatures, and unpredictable shelter. Why do generalists thrive there while specialists rarely establish populations?

- (A) Generalists tolerate varied diets and conditions so they persist in cities.
- (B) Faster reproduction aids spread but does not explain urban tolerance.
- (C) This reverses the pattern by claiming generalists dominate stable forests.
- (D) Specialists fail because unpredictable resources and conditions exceed narrow tolerances.

**Answer: (A)** Broad tolerance of diet and microclimate lets generalists survive urban unpredictability. Flexible diets and tolerance of temperature and shelter variation reduce reliance on specific habitats or food sources.

### Question 7

In a temperate grassland, a severe drought reduces plant diversity and shifts the remaining vegetation toward drought-resistant species. Which statement best explains the relationship between environmental change and population survival for generalist versus specialist herbivores in this ecosystem?

- (A) Generalist herbivores maintain stable populations because their broad dietary tolerance allows them to exploit the drought-resistant plants now available, while specialists cannot switch food sources.
- (B) Both generalist and specialist herbivores decline in population because reduced plant diversity limits food availability, but specialists decline more severely due to their narrow dietary requirements.
- (C) Generalist herbivores maintain stable populations because they typically have smaller population sizes requiring fewer total resources, while specialist populations decline due to their larger resource demands.
- (D) Specialist herbivores maintain stable populations because the drought-resistant plants now dominating represent a constant, predictable food source that favors specialized feeding strategies, while generalists decline due to reduced dietary options.

**Answer: (A)** Connecting environmental change to species-specific tolerance mechanisms reveals why generalists persist through disturbance. Generalists' broad niche enables dietary flexibility—they can consume newly available drought-resistant plants—while specialists dependent on specific plant species lose their primary food source, demonstrating the core difference in adaptability between these groups.

### Question 8

A river's water temperature rose gradually from 12°C to 18°C over 20 years. Species A, a generalist, remained relatively stable while Species B, a specialist, declined sharply after year 10. Which statement best explains these divergent population responses?

- (A) Species A persists due to broad thermal tolerance and dietary flexibility.
- (B) Species A increases by outcompeting Species B through aggressive territory defense.
- (C) Both species decline because warmer water reduces oxygen availability for all fish.
- (D) Species B adapts via rapid evolution of heat tolerance within 20 years.

**Answer: (A)** Generalist traits let Species A continue feeding and reproducing across the warming range. Species B's narrow thermal niche prevents physiological adjustment, producing the sharp decline after year 10.

### Question 9

Over 15 years of expanding urban settlement, brown rat populations rose 300% while native wood mice fell 85%. Which statement best explains the divergent population responses to habitat modification?

- (A) Brown rats exploit human food and shelter resources while wood mice cannot.
- (B) Brown rats show flexible foraging and nesting, wood mice lack that flexibility.
- (C) Both species decline but specialists decline more severely due to narrow habitat needs.
- (D) Brown rats tolerate urban pollutants better than wood mice, aiding their growth.

**Answer: (A)** Generalist traits let brown rats exploit human food waste and shelter, boosting their numbers. Wood mice require specific forest resources and cannot use urban resources, causing their decline.

### Question 10

Over 30 years, a forest became fragmented into smaller, isolated patches. During this period, a specialist bird that needs large territories and interior forest declined 90%, while a generalist bird declined 15%. Which statement best explains the difference?

- (A) Specialist loses large interior habitat from fragmentation while generalist uses edges.
- (B) Genetic bottlenecks can occur but follow population decline due to habitat loss.
- (C) Both species would decline equally because total habitat area decreases for all species.
- (D) Specialist population remains stable by adapting to smaller territories and edges.

**Answer: (A)** Specialists decline when fragmentation removes the continuous interior habitat they require. Generalists tolerate edge conditions and smaller patches, so they persist with less decline.

## Review the Unit

- [3.1 Generalist and Specialist Species](/ap-enviro/unit-3/generalist-specialist-species/study-guide/bDVsgp06AHy4azzehZxP)
- [3.2 K-Selected r-Selected Species](/ap-enviro/unit-3/k-selected-r-selected-species/study-guide/Z3qZXHWAWrjSleoDvISp)
- [3.3 Survivorship Curves](/ap-enviro/unit-3/survivorship-curves/study-guide/4vVOKIxNz6i89ct8qb0U)
- [3.4 Carrying Capacity](/ap-enviro/unit-3/carrying-capacity/study-guide/v2LtCnBGi4ceCTmPao24)
- [3.5 Population Growth and Resource Availability](/ap-enviro/unit-3/population-growth-resource-availability/study-guide/VJyMj5rEj3GLAlaNlQcL)
- [3.6 Age Structure Diagrams](/ap-enviro/unit-3/age-structure-diagrams/study-guide/Dh16VKqnmPyH9TaTfLtY)
- [3.7 Total Fertility Rate](/ap-enviro/unit-3/total-fertility-rate/study-guide/XA2EPXmkHOhfLa86fbEw)
- [3.8 Human Population Dynamics](/ap-enviro/unit-3/human-population-dynamics/study-guide/g1a8MMUTre14Qa5OfsU1)
- [3.9 Demographic Transition](/ap-enviro/unit-3/demographic-transition/study-guide/8tHV3Zxw9IJ9wEzNcGOE)

## Other Unit Tests

- [Unit 1: The Living World: Ecosystems](/ap-enviro/unit-test/1)
- [Unit 2: The Living World: Biodiversity](/ap-enviro/unit-test/2)
- [Unit 4: Earth Systems & Resources](/ap-enviro/unit-test/4)
- [Unit 5: Land & Water Use](/ap-enviro/unit-test/5)
- [Unit 6: Energy Resources & Consumption](/ap-enviro/unit-test/6)
- [Unit 7: Atmospheric Pollution](/ap-enviro/unit-test/7)
- [Unit 8: Aquatic & Terrestrial Pollution](/ap-enviro/unit-test/8)
- [Unit 9: Global Change](/ap-enviro/unit-test/9)

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