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🌎 Free AP Environmental Science Study Guide

AP Environmental Science · All 9 Units

Master AP Environmental Science from ecosystems through global change. Flashcards, cheat sheets, essential terms, practice questions, and visual reviews for all 9 units — all completely free.

9 units covered
175+ practice questions
175+ flashcards
College Board aligned
100% free

Choose your unit

Each unit has 6 study resources — flashcards, cheat sheet, essential terms, practice questions, visual review, and FRQ practice.

🌳
Unit 1
Foundations
The Living World: Ecosystems
Ecosystems, biomes, and the biogeochemical cycles — carbon, nitrogen, and phosphorus — that move matter through the living world.
📊 6–8% of exam
Start Unit 1 →
🦋
Unit 2
Diversity of Life
The Living World: Biodiversity
Island biogeography, ecosystem services, and the causes and consequences of biodiversity loss.
📊 6–8% of exam
Start Unit 2 →
📈
Unit 3
Growth & Limits
Populations
Population ecology, carrying capacity, age-structure diagrams, and human population dynamics.
📊 10–15% of exam
Start Unit 3 →
🌍
Unit 4
Earth's Engine
Earth Systems & Resources
Plate tectonics, soil formation, weather and climate, and the global wind and ocean circulation patterns.
📊 12–15% of exam
Start Unit 4 →
🌾
Unit 5
Human Footprint
Land & Water Use
Agriculture, deforestation, mining, fishing, and the sustainability tradeoffs of how we use land and water.
📊 10–15% of exam
Start Unit 5 →
Unit 6
Powering Society
Energy Resources & Consumption
Fossil fuels, nuclear power, and renewable energy sources — how we generate and consume energy, and at what cost.
📊 10–15% of exam
Start Unit 6 →
🏭
Unit 7
The Sky Above
Atmospheric Pollution
Smog, acid rain, ozone depletion, and the sources and impacts of air pollution on human health and ecosystems.
📊 7–10% of exam
Start Unit 7 →
🚯
Unit 8
Land & Water
Aquatic & Terrestrial Pollution
Eutrophication, endocrine disruptors, solid waste, and the human health effects of pollutants in water and on land.
📊 7–10% of exam
Start Unit 8 →
🌡️
Unit 9
The Big Picture
Global Change
Ozone depletion, climate change, invasive species, and ocean acidification — the largest unit on the exam.
📊 13–19% of exam
Start Unit 9 →

About AP Environmental Science

AP Environmental Science (APES) is a college-level interdisciplinary course that blends biology, chemistry, geology, and geography to study how the natural world works and how human activity affects it. The course builds from ecosystems and biodiversity, through populations and Earth's physical systems, to how humans use land, water, and energy — and the pollution and global change that result.

This page covers all 9 units — The Living World: Ecosystems, The Living World: Biodiversity, Populations, Earth Systems & Resources, Land & Water Use, Energy Resources & Consumption, Atmospheric Pollution, Aquatic & Terrestrial Pollution, and Global Change.

Every page on this site is aligned to the College Board's official AP Environmental Science Course and Exam Description and completely free. Use what works for your study style — flashcards for active recall, the cheat sheet for a one-page overview, or practice questions to test yourself before the exam.

What's included in each unit

Every unit has the same 6 study resources, designed for different learning styles.

🗂
Flashcards
Interactive cards per unit
🗺
Cheat Sheet
One-page visual summary
Essentials
Key terms and big ideas
🎨
Visual Review
Slide-by-slide walkthrough
📝
Practice MCQ
Exam-style questions
FRQ Practice
Free-response practice

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