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Verified for the 2027 AP exam

AP Environmental Science Study Guide & Review

Connect ecosystems, Earth systems, resources, pollution and global change through causal models, investigation, quantitative evidence and balanced environmental solutions across the current AP Environmental Science course.

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  1. 01Learn concepts
  2. 02Practise questions
  3. 03Review mistakes

Syllabus knowledge tree

Explore all nine AP Environmental Science units

Navigate 99 Topics across the nine official Units, from ecosystems and biodiversity to resource use, pollution and global change. Use current MCQ ranges to prioritize without breaking cross-Unit system dependencies.

9
syllabus groups
99
mapped topics

Preview the course map

Explore the course units and topics. Sign in to open the full mastery workspace and see your progress.

Unit 1: The Living World: Ecosystems
1.1 Introduction to Ecosystems
1.2 Terrestrial Biomes
1.3 Aquatic Biomes
1.4 The Carbon Cycle
1.5 The Nitrogen Cycle
1.6 The Phosphorus Cycle
1.7 The Hydrologic (Water) Cycle
1.8 Primary Productivity
1.9 Trophic Levels
1.10 Energy Flow and the 10% Rule
1.11 Food Chains and Food Webs
Unit 2: The Living World: Biodiversity
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
Unit 3: Populations
3.1 Generalist and Specialist Species
3.2 K-Selected r-Selected Species
3.3 Survivorship Curves
3.4 Carrying Capacity
3.5 Population Growth and Resource Availability
3.6 Age Structure Diagrams
3.7 Total Fertility Rate
3.8 Human Population Dynamics
3.9 Demographic Transition
Unit 4: Earth Systems and Resources
4.1 Plate Tectonics
4.2 Soil Formation and Erosion
4.3 Soil Composition and Properties
4.4 Earth’s Atmosphere
4.5 Global Wind Patterns
4.6 Watersheds
4.7 Solar Radiation and Earth’s Seasons
4.8 Earth’s Geography and Climate
4.9 El Niño and La Niña
Unit 5: Land and Water Use
5.1 The Tragedy of the Commons
5.2 Clearcutting
5.3 The Green Revolution
5.4 Impact of Agricultural Practices
5.5 Irrigation Methods
5.6 Pest Control Methods
5.7 Meat Production Methods
5.8 Impacts of Overfishing
5.9 Impacts of Mining
5.10 Impacts of Urbanization
5.11 Ecological Footprints
5.12 Introduction to Sustainability
5.13 Methods to Reduce Urban Runoff
5.14 Integrated Pest Management
5.15 Sustainable Agriculture
5.16 Aquaculture
5.17 Sustainable Forestry
Unit 6: Energy Resources and Consumption
6.1 Renewable and Nonrenewable Resources
6.2 Global Energy Consumption
6.3 Fuel Types and Uses
6.4 Distribution of Natural Energy Resources
6.5 Fossil Fuels
6.6 Nuclear Power
6.7 Energy from Biomass
6.8 Solar Energy
6.9 Hydroelectric Power
6.10 Geothermal Energy
6.11 Hydrogen Fuel Cell
6.12 Wind Energy
6.13 Energy Conservation
Unit 7: Atmospheric Pollution
7.1 Introduction to Air Pollution
7.2 Photochemical Smog
7.3 Thermal Inversion
7.4 Atmospheric CO₂ and Particulates
7.5 Indoor Air Pollutants
7.6 Reduction of Air Pollutants
7.7 Acid Rain
7.8 Noise Pollution
Unit 8: Aquatic and Terrestrial Pollution
8.1 Sources of Pollution
8.2 Human Impacts on Ecosystems
8.3 Endocrine Disruptors
8.4 Human Impacts on Wetlands and Mangroves
8.5 Eutrophication
8.6 Thermal Pollution
8.7 Persistent Organic Pollutants (POPs)
8.8 Bioaccumulation and Biomagnification
8.9 Solid Waste Disposal
8.10 Waste Reduction Methods
8.11 Sewage Treatment
8.12 Lethal Dose 50% (LD₅₀)
8.13 Dose Response Curve
8.14 Pollution and Human Health
8.15 Pathogens and Infectious Diseases
Unit 9: Global Change
9.1 Stratospheric Ozone Depletion
9.2 Reducing Ozone Depletion
9.3 The Greenhouse Effect
9.4 Increases in the Greenhouse Gases
9.5 Global Climate Change
9.6 Ocean Warming
9.7 Ocean Acidification
9.8 Invasive Species
9.9 Endangered Species
9.10 Human Impacts on Biodiversity

How to study AP Environmental Science

AP Environmental Science improves when Units are connected as systems rather than memorized as separate fact lists. Use the nine-unit syllabus map to trace an environmental driver through energy or matter flows, ecological or Earth-system responses, human consequences and possible interventions. Support each link with a model, map, text source, graph, field observation or calculation, then state uncertainty and trade-offs.

Rebuild a weak causal model in Concept, check retrieval in Mastery and apply it to unfamiliar evidence in the Question Bank. After marking, classify the first failure as concept, system link, source interpretation, investigation design, data, calculation, units or solution evaluation. Repair that category and answer a matched question without notes.

Practise environmental systems with evidence

Combine causal explanation, visual and text sources, field or laboratory design, quantitative data and solution trade-offs across representative AP Environmental Science Topics.

Ecosystems, biodiversity and populations

Energy flow, biogeochemical cycles, species interactions, population change and conservation

Draw the system boundary and trace energy or matter before explaining population or biodiversity effects. Use a graph, model or field observation as evidence, distinguish correlation from mechanism and test whether the proposed conservation response addresses the actual driver.

Practise living systems

Earth systems and resource use

Geology, soil, atmosphere, agriculture, forestry, mining and water use

Connect the natural process to the extraction or land-use decision, then identify downstream impacts across scales. Compare resource strategies with measurable criteria such as yield, erosion, water demand, emissions, habitat change and long-term sustainability.

Practise resources

Energy and atmospheric pollution

Energy sources, consumption, combustion, air pollutants, smog and acid deposition

Track fuel or energy conversion through emissions, transport, chemical transformation and exposure. Interpret concentration or energy data, keep units visible and evaluate controls by mechanism, effectiveness, cost and unintended environmental consequences.

Practise energy and air

Water, land pollution and global change

Waste, toxicology, water pollution, ozone, climate change and ocean effects

Identify source, pathway, receptor and response before interpreting evidence. Separate local from global scale, calculate rates or concentrations when required and compare prevention, mitigation and adaptation without claiming that one intervention removes every trade-off.

Practise pollution and change

Investigation, data and FRQs

Experimental design, quantitative interpretation, calculations and environmental solutions

Define the question, variables, control and feasible measurement before collecting or analyzing data. Show setup and units, interpret patterns and uncertainty and make a solution claim no broader than the evidence, mechanism and stated constraints can support.

Practise APES FRQs

Where to start

Begin with one known environmental Topic or use a diagnostic to identify the earliest repeated system, evidence, calculation or solution failure.

Choose your starting point

  1. I know the weak Topic

    Open its exact Unit and identify the system boundary, causal chain, evidence type and quantitative relationship involved.

    Browse all nine Units

  2. I do not know what is weak

    Use a mixed diagnostic and stop at the first repeated concept, data, investigation, calculation or trade-off error.

    Start a diagnostic

Choose the right starting point

  1. Build the system explanation

    Trace energy, matter and interactions through the environmental process, then predict a measurable change.

    Review a Concept

  2. Interpret evidence and calculate

    Read the source, graph, map or data set, choose the relationship, show units and interpret the result.

    Check Mastery

  3. Evaluate and repair

    Propose a justified solution, compare benefits, costs and limitations and correct the first failed reasoning step.

    Practise questions

AP Environmental Science exam format for 2027

The verified 2027 exam is fully digital in Bluebook: 80 multiple-choice questions in 90 minutes and three distinct free-response tasks in 70 minutes.

Paper / componentQuestionsTime% of grade
Section I: Multiple Choice80 questionsIndividual questions and sets use quantitative data, qualitative information, models, maps and text sources in Bluebook.How to prepare: Practise timed mixed stimuli, causal explanation, source evaluation, graph and data interpretation and efficient calculations rather than definition-only recall.1 hour 30 minutes60%
Section II: Free Response3 questionsFully digital tasks require designing an investigation, analyzing quantitative data and analyzing an environmental problem using calculations.How to prepare: Train each task separately: specify methods and variables, interpret evidence, show calculations and units and justify solutions with benefits, costs and limitations.1 hour 10 minutes40%

SourceCollege Board · AP Environmental Science ExamAP Environmental Science · May 2027 exam

AP Environmental Science questions

College Board requires at least 25% of instructional time in hands-on, inquiry-based laboratory investigations and/or fieldwork distributed through the course. Students should record evidence in lab reports, mini-posters or print or digital notebooks and connect methods, data and limitations to conclusions.

No. College Board permits a four-function calculator with square root or a scientific nongraphing calculator on both sections. Storage-capable handhelds, including graphing calculators, are not allowed for the 2027 AP Environmental Science exam; Bluebook supplies a Desmos scientific calculator.

No printed booklet is supplied for AP Environmental Science. Official reference information is available only in Bluebook during test preview and on exam day. Use the current CED to prepare for that material instead of treating an unofficial formula or cheat sheet as exam authority.

The challenge is breadth plus transfer: a question can combine ecosystem or Earth-system knowledge with a graph, text source, experiment, calculation and policy trade-off. Study one causal chain at a time, then practise applying it to unfamiliar evidence instead of memorizing disconnected vocabulary.