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AP® Environmental Science

The Best AP® Environmental Science Review: Topic Summaries, Examples, and Free Practice

Welcome to Albert’s collection of science topic reviews for teaching and reviewing AP® Environmental Science Teachers and students can explore our easy-to-follow guides below for use at home or in the classroom.

Overview and Scoring

What is AP® Environmental Science? How is the AP® exam scored?

Discover key AP® Environmental Science concepts, exam structure, and scoring details. Understand how your exam is graded and find strategies to achieve your target score.

Subject icon for The Best AP® Environmental Science Review Guide for 2025

The Best AP® Environmental Science Review Guide for 2025

Subject icon for AP® Environmental Science FAQ: Everything You Need to Know for 2025

AP® Environmental Science FAQ: Everything You Need to Know for 2025

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Is AP® Environmental Science Hard?

Subject icon for AP® Environmental Science Score Calculator

AP® Environmental Science Score Calculator

Unit 1 | The Living World: Ecosystems

How do species and populations fulfill their niches in their community and ecosystem? Which abiotic processes allow for survival of the living world?

The review articles below introduce the foundational ecological concepts of AP® Environmental Science. From exploring the global distribution of biomes to tracing the flow of energy and the steps of the carbon, nitrogen, and phosphorus cycles, you'll gain insight into how ecosystems function and sustain life on Earth.

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

Why is biodiversity essential to the stability and resilience of ecosystems? How do ecosystem services support both natural systems and human populations?

The review articles below explore the value of biodiversity and the ecological roles played by species at every level. Learn how genetic, species, and habitat diversity contribute to ecosystem function—and how human activity can threaten or preserve these vital systems.

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

What factors influence population growth and decline in ecosystems? How do species' reproductive strategies and survivorship curves shape population dynamics?

The review articles below break down the key concepts related to population ecology. From carrying capacity to age structure diagrams, learn how to interpret population trends and predict how species interact with environmental resources over time.

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

How do Earth’s systems interact to shape the environment? What are the environmental consequences of natural and human-induced changes to Earth’s resources?

The review articles below examine the physical systems that support life on Earth, including soil formation, plate tectonics, and weather patterns. Understand how these systems influence climate, natural hazards, and the availability of water and other vital 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

How do agricultural and industrial practices impact ecosystems and natural resources? What are the trade-offs between resource extraction and sustainable land management?

The review articles below explore how land and water resources are used to meet human needs and the environmental costs of those uses. From deforestation and overgrazing to aquaculture and irrigation, learn how various practices affect soil health, water quality, and ecosystem balance.

5.1 | The Tragedy of the Commons

5.2 | Clearcutting

5.3 | The Green Revolution

5.4 | Impacts 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 Runof

5.14 | Integrated Pest Management

5.15 | Sustainable Agriculture

5.16 | Aquaculture

5.17 | Sustainable Forestry

Unit 6 | Energy Resources and Consumption

What are the environmental impacts of renewable and nonrenewable energy sources? How can societies reduce energy consumption and transition to more sustainable energy use?

The review articles below cover the types of energy humans rely on—from fossil fuels and nuclear power to wind and solar. Analyze the advantages and disadvantages of each energy source, and explore conservation strategies to reduce environmental impact and improve efficiency.

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

What are the major sources and types of air pollution? How does air pollution affect environmental and human health, and what can be done to reduce it?

The review articles below explain the causes and effects of atmospheric pollutants, from smog and acid rain to indoor air contaminants. Learn how emissions from transportation, industry, and agriculture affect air quality—and how policy and technology can help mitigate these impacts.

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

What are the major sources and impacts of pollution in water and land ecosystems? How can pollution be measured, managed, and reduced to protect the environment?

The review articles below explore the causes and consequences of pollution in aquatic and terrestrial environments, including oil spills, eutrophication, solid waste, and heavy metals. Discover how scientists monitor pollution levels and what methods are used to mitigate environmental damage.

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

How does climate change influence ecosystems and biodiversity around the world? What human activities contribute to global environmental change, and how can we respond?

The review articles below examine the science behind global environmental change, including rising greenhouse gas levels, habitat loss, invasive species, and ocean acidification. Understand how global systems are shifting—and what solutions exist to address environmental challenges at a planetary scale.

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

Study and Test Prep

How do I ace the AP® Environmental Science exam? What are top study strategies?

These articles offer insights into essential exam topics and effective study methods. Discover tips for test-taking, managing your time, and understanding the exam format to boost your confidence and improve your scores.

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The Ultimate List of AP® Environmental Science Tips

Subject icon for One Month AP® Environmental Science Study Guide

One Month AP® Environmental Science Study Guide

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How to Study for AP® Environmental Science

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