AP Environmental Science Unit 2 practice questions
Try 10 multiple-choice questions from Unit 2 here. Pick an answer to see why it's right or wrong, then take the timed test above for a full AP-style set.
Question 1
Researchers studied the provisioning ecosystem service of freshwater supply by measuring water flow and quality at a single downstream location in a river once per month. If they modified the study to include measurements at multiple upstream locations representing different land uses (forest, agriculture, urban development) and increased sampling frequency to weekly, how would this modification most likely affect their ability to identify sources of water quality disruption?
Spatial patterns of water quality degradation could be linked to specific land uses, and temporal variability could reveal how disruptions respond to seasonal changes and precipitation events.
Water quality measurements would show improvement because sampling at upstream locations would capture cleaner water before it becomes polluted.
The study would become less reliable because different land uses have different natural water quality characteristics, introducing confounding variables that mask the true effect of human disruption.
Weekly measurements would produce more variable data than monthly measurements, making it harder to identify true trends in water quality.
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Answer: (A)
Recognizing that spatial replication (multiple upstream locations with different land uses) and temporal replication (weekly sampling) allow researchers to trace water quality disruptions to their sources. This modification reveals that water quality disruptions are not uniform but depend on specific human activities and vary temporally with weather and seasonal patterns. Understanding these patterns is essential for assessing how human disruptions compromise the provisioning service of freshwater supply.
Question 2
Researchers measured nitrate at one well 500 meters downstream from farmland. If they instead sampled wells at 100, 300, 500, and 1000 meters monthly for a year, how would this change their understanding of nitrogen pollution impacts?
Reveal spatial and seasonal nitrate patterns showing reduced purification nearer the source.
Claim concentrations would decrease because sampling more locations spreads pollution
Argue results are less reliable due to unrelated hydrogeological differences among wells.
Assert annual averages would increase simply because more wells were sampled.
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Answer: (A)
Adding spatial and temporal replication reveals contamination gradients and seasonal flux. Sampling multiple distances and months lets researchers link agricultural runoff to reduced groundwater purification.
Question 3
Researchers measured annual crop yield in one field for five years. If they instead sampled ten fields across varied soils, elevations, and management within the same region, how would their conclusions about agricultural productivity most likely change?
Reveal how soil, elevation, and management drive yield differences across fields.
Average yield would increase simply because more fields were measured.
Introduce confounding variables that would be mistaken for climate effects.
Reduce temporal precision because each field would have fewer repeated measurements.
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Answer: (A)
Spatial replication lets researchers separate environmental and management effects from temporal variation. Sampling multiple fields uncovers which factors drive productivity and shows context dependent responses to disturbance.
Question 4
Scientists surveyed visitors at one popular trailhead on summer weekends to estimate a forest's cultural ecosystem service value. If they instead surveyed multiple trailheads across all seasons and on both weekdays and weekends, which change in understanding is most likely?
Seasonal and spatial variation in recreational use and satisfaction would emerge.
Average satisfaction would increase simply because more visitors were surveyed.
The study would become less reliable due to confounding by differing visitor demographics.
Satisfaction scores would vary by season and trailhead due to environmental differences.
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Answer: (A)
Temporal and spatial replication reveals heterogeneous patterns of visitor use and satisfaction. That variation shows how disturbances and management affect cultural services differently across locations, seasons, and user groups.
Question 5
Oyster reefs filter large volumes of water by removing phytoplankton and suspended particles, which improves water clarity and reduces excess algal growth. Oyster populations have declined dramatically in many estuaries due to overharvesting, disease, and habitat degradation. Which of the following best describes the ecosystem service disruption resulting from oyster reef decline?
Loss of the regulating service of water filtration allows phytoplankton and suspended particles to accumulate, reducing water clarity and increasing eutrophication risk
Loss of the provisioning service of oyster meat for human consumption reduces food availability for coastal communities
Oyster reef decline increases the supporting service of nutrient cycling by allowing more decomposition of dead organisms in the water column
Loss of the cultural service of oyster harvesting as a traditional practice eliminates the regulating service of water filtration entirely from estuarine ecosystems
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Answer: (A)
Understanding this disruption requires explaining the mechanism by which oysters filter water and describing how their decline removes this regulating service. The answer demonstrates that when oyster populations decline, the physical filtration process fails, allowing excess nutrients and particles to accumulate, which increases eutrophication risk. This shows mechanistic understanding of how a regulating service functions and what happens when it is disrupted.
Question 6
Wetlands filter pollutants and cycle nutrients, providing water purification. When wetlands are drained for agriculture and water bypasses them, which ecosystem service disruption best explains increased nutrient loading and downstream eutrophication?
Loss of regulating water purification causing nutrient loading and downstream eutrophication
Loss of provisioning services like fish and waterfowl for human consumption
Loss of supporting nutrient cycling that impairs but does not stop other ecosystem services
Loss of cultural services such as recreation and aesthetic enjoyment of wetlands
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Answer: (A)
Wetlands perform a regulating service by filtering pollutants and cycling nutrients. Draining them removes that filtration so nutrients travel downstream, increasing algal growth and causing eutrophication.
Question 7
Coral reefs support food webs and protect coasts by attenuating waves. Ocean acidification lowers seawater pH and reduces carbonate ion availability. How does acidification disrupt reef ecosystem services?
Reduced carbonate limits coral calcification, weakening reefs and coastal protection.
Additional dissolved CO2 does not boost coral calcification or skeletal growth.
Bleaching results mainly from warming rather than lowered pH and affects tourism.
Acidification can harm fish larvae but mainly reduces reef structure and services.
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Answer: (A)
Reduced carbonate availability slows coral calcification and weakens reef frameworks. Weaker frameworks reduce wave attenuation and simplify habitat, impairing regulating and supporting services.
Question 8
Mangroves trap terrestrial sediment and provide nurseries for commercially important fish. When mangroves are cleared for shrimp ponds and trapped sediment continues into coastal waters, which choice best describes the disrupted ecosystem service and its consequence?
Loss of sediment trapping increases coastal turbidity and smothers seagrass nurseries.
Loss of mangrove timber provisioning reduces income for communities relying on wood products.
Loss of nutrient cycling would force all fish to permanently leave coastal waters.
Loss of mangrove aesthetic value is not offset by shrimp aquaculture benefits.
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Answer: (A)
Loss of sediment trapping increases turbidity and deposits sediment in seagrass beds, degrading nursery habitat. That habitat loss reduces recruitment of commercially important juvenile fish.
Question 9
Honeybee declines from pesticides, habitat loss, and disease reduce pollination for almonds and apples. Which best describes the ecosystem service disruption?
Loss of pollination is a regulating service decline that lowers crop yields.
Mislabels pollination as a supporting service and overstates reproductive collapse.
Declining bee populations decrease honey production rather than increase it.
Confuses cultural value of beekeeping with loss of pollination functions.
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Answer: (A)
Pollination is a regulating service whose loss lowers pollination rates and crop yields. This reduction cascades into provisioning services by decreasing fruit and seed production in almonds and apples.
Question 10
A coastal wetland was converted to aquaculture over 10 years. Estuary nitrogen rose from 0.8 mg/L at year 0 to 1.2 mg/L at year 3, 2.1 mg/L at year 6, and 3.4 mg/L at year 10. Fish species declined from 47 to 31, with the steepest losses after year 6. Which conclusion about disruption of ecosystem services is best supported by these data?
Rising nitrogen from aquaculture runoff correlates with fish loss and reduced purification.
Fish declined due to relocation to aquaculture ponds rather than true loss.
Nitrogen levels and fish diversity appear unrelated, so aquaculture has no impact.
Fish declines were uniform, so wetland conversion caused immediate constant service loss.
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Answer: (A)
Rising nitrogen corresponds with accelerated fish losses and signals impaired regulating and supporting services. The steepest declines after year 6 coincide with nitrogen exceeding 2.1 mg/L, consistent with eutrophication reducing water purification and habitat quality.
What's on the AP Environmental Science Unit 2 practice test
The standard version takes about 70 minutes and follows the timing and directions of the AP exam, sized to one unit:
- 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)
Questions are drawn from 2257 multiple-choice questions and 45 FRQs written for Unit 2, The Living World: Biodiversity.
Practice AP Environmental Science Unit 2 FRQs
Answer the unit's free-response questions one at a time and get a score on every part.
- FRQ 1 – Design an Investigation (19 questions)
- FRQ 2 – Analyze and Interpret Quantitative Data (14 questions)
- FRQ 3 – Analyze an Environmental Problem Doing Calculations (12 questions)
Review Unit 2 before you start
- 2.1 Introduction to Biodiversity
- 2.2 Ecosystem Services
- 2.3 Island Biogeography
- 2.4 Ecological Tolerance
- 2.5 Natural Disruptions to Ecosystems
- 2.6 Adaptations
- 2.7 Ecological Succession