AP® Environmental Science Study Guide
Comprehensive AP® Environmental Science guide covering all nine units of the 2025 CED: Ecosystems, Biodiversity, Populations, Earth Systems and Resources, Land and Water Use, Energy Resources and Consumption, Atmospheric Pollution, Aquatic and Terrestrial Pollution, and Global Change. Includes the four big ideas (energy transfer, Earth systems interactions, species-environment interactions, sustainability), the four science practices, and a dedicated FRQ-strategy capstone with dimensional-analysis calculations (calculator allowed) for the three FRQ types (design an investigation; analyze a problem + propose a solution; analyze + calculations).
The Prep Den AP® Environmental Science study guide is your complete companion for revising the course: full topic-by-topic coverage, interactive flashcards, practice quizzes with worked explanations, a key-terms bank, and exam-technique tips. Use it as your main study guide or as a supplement to your textbook and class notes.
Topics Covered
What you get
Unit 1: The Living World: Ecosystems
THE BIG PICTURE. Unit 1 (6–8%) opens APES with the foundational ecology toolkit: how energy and matter move through ecosystems. Three ideas dominate: biomes (the climate-defined regions that shape what lives where), energy flow (one-way, through trophic levels, governed by the 10% rule), and biogeochemical cycles (the cyclical movement of carbon, nitrogen, phosphorus, water, and other key elements).
Sample Flashcards
A grassland has 10,000 kcal/m²/yr of producer biomass. Using the 10% rule, how much energy is available at the secondary-consumer (carnivore) level?
100 kcal/m²/yr. Producer (10,000) → herbivore (1,000) → carnivore (100). Each transfer keeps 10%.
By the time you reach tertiary consumers, very little energy is left, explaining why apex predators are rare.
Distinguish GPP and NPP.
GPP (gross primary productivity) = total energy captured by photosynthesis. NPP = GPP minus the energy producers use for their own respiration (R): .
NPP is what is available to consumers as food.
Sample Key Terms
Ecosystem
Community of living (biotic) organisms plus their non-living (abiotic) environment, interacting as a system.
Biome
Large geographic region defined by climate (temperature + precipitation) and characteristic dominant vegetation. Examples: tropical rainforest, desert, tundra.
Autotroph (Producer)
Organism that produces its own food via photosynthesis (most) or chemosynthesis (some bacteria). Base of all food chains.
What's Covered
- Unit 1: The Living World: Ecosystems
- Unit 2: The Living World: Biodiversity
- Unit 3: Populations
- Unit 4: Earth Systems and Resources
- Unit 5: Land and Water Use
- Unit 6: Energy Resources and Consumption
- Unit 7: Atmospheric Pollution
- Unit 8: Aquatic and Terrestrial Pollution
- Unit 9: Global Change
- Exam Skills: Science Practices, Calculations & FRQ Strategy
10 topics · 120+ flashcards · quizzes included
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