AP Environmental Science · Cram chart

APES cheat sheet: a unit-by-unit cram chart.

Nine units, one page. Each row gives you the idea the unit is really testing, the detail you have to know, and the mistake that costs the most marks. This APES cram chart is built for the last week, when you are revising an AP Environmental Science review you have already read once.

Updated September 2026By Mahmudul HasanPart of AP Environmental Science Review

What an APES cheat sheet is (and what you can bring)

A cheat sheet here means a condensed, high-yield study tool, not something you take into the exam. Most people searching for an AP Environmental Science cheat sheet want the nine units in one place rather than a textbook, and that is what this is: what you review the night before to lock in the vocabulary and the key ideas.

What the exam actually gives you

You cannot bring notes of any kind. The exam is fully digital, taken in the Bluebook app, so there is no paper booklet and nothing to hand back.

A calculator is allowed on both sections, and Bluebook has a Desmos scientific calculator built in, so you do not have to bring one at all. If you would rather use your own, check the model first. College Board permits a four-function calculator with a square root key, or a scientific nongraphing model. From the 2027 exam, handheld calculators with storage capabilities, including graphing calculators, are not allowed. That rule is new, so do not go by an older guide: it is the kind of thing that gets a calculator refused at the door.

One thing worth being clear about, because much of the internet has it wrong: College Board has never published an equation sheet for AP Environmental Science the way it does for Biology, Chemistry and Physics. There is reference information inside Bluebook, but its contents are unpublished and it is not in the course and exam description. Treat the equations as yours to know.

The shape of the exam

The whole thing runs 2 hours 40 minutes. Section I is 80 multiple-choice questions in 90 minutes and is worth 60% of your score. Section II is 3 free-response questions in 70 minutes, worth the other 40%: design an investigation, analyze and interpret quantitative data, and analyze an environmental problem doing calculations. Each is worth 10 points, and College Board suggests about 22 minutes on each. Full detail is on the AP Environmental Science exam page.

What makes a cram chart more useful than a fact dump is context: the one idea each unit is really testing, and the vague-answer trap that turns a right idea into a lost point on the free response.

Cheat sheet vs the formula sheet

They do different jobs. The AP Environmental Science formula sheet collects the population, energy, and pollution equations you use for the math questions, which matters more now that you know nobody hands them to you. This cheat sheet is broader and concept-first: it covers the key idea, must-know detail, and common mistake for every unit, which the formula sheet leaves out.

The unit-by-unit cram chart

Ordered as College Board weights them, Unit 9 is the heaviest at 15–20% and Units 1 and 2 the lightest at 6–8%. Every weighting below is the share of the multiple-choice section.

Exam weighting by unit, heaviest first. Solid shows the lower bound, the lighter extension the upper. Figures from the College Board course and exam description.

Unit 1 — The Living World: Ecosystems 6–8%

Idea: energy and matter move through ecosystems. Must-know: food webs, the 10% rule, and the carbon, nitrogen, phosphorus, and hydrologic cycles. Watch out: confusing the cycles, or naming one without describing its steps and its reservoir, the slowest stage.

Unit 2 — The Living World: Biodiversity 6–8%

Idea: diversity builds ecosystem resilience. Must-know: species vs genetic diversity, ecosystem services, ecological succession, and island biogeography. Watch out: confusing ecosystem services with ecological function, and biodiversity with genetic diversity.

Unit 3 — Populations 10–15%

Idea: how populations grow and are limited. Must-know: J- vs S-curves, carrying capacity, survivorship, the rule of 70, and the demographic transition. Watch out: forgetting to show the growth-rate working. math-heavy

Unit 4 — Earth Systems and Resources 10–15%

Idea: the physical planet and its resources. Must-know: plate tectonics, soil horizons and texture, atmospheric layers, and watersheds. Watch out: skimming the soil and atmosphere detail, then having to tell convergent, divergent and transform boundaries apart on a map.

Unit 5 — Land and Water Use 10–15%

Idea: how humans use land and what it costs. Must-know: agriculture, mining, urbanization, sustainability, and the Tragedy of the Commons. Watch out: answering with a vague practice instead of naming a specific one.

Unit 6 — Energy Resources and Consumption 10–15%

Idea: where energy comes from and its trade-offs. Must-know: fossil fuels vs renewables, energy efficiency, and power × time. Watch out: dropping the units, or stopping halfway through a multi-step conversion. math-heavy

Unit 7 — Atmospheric Pollution 7–10%

Idea: air pollutants and their effects. Must-know: primary vs secondary pollutants, smog, thermal inversions, indoor air pollutants, acid rain, and the Clean Air Act. Watch out: confusing photochemical with industrial smog, and not naming the illness a pollutant causes.

Unit 8 — Aquatic and Terrestrial Pollution 7–10%

Idea: pollution in water and on land. Must-know: point vs nonpoint sources, eutrophication, dose response, and solid waste. Watch out: confusing bioaccumulation with biomagnification.

Unit 9 — Global Change 15–20%

Idea: large-scale human impact on the planet. Must-know: ozone depletion, greenhouse gases and global warming, ocean warming and acidification, and invasive species. Watch out: confusing ozone depletion with the greenhouse effect, or assuming a small population is automatically a threatened one.

The environmental laws you have to know

This is the one closed list in the course, which makes it the most efficient thing on the page to memorise. College Board names ten required policies, tied to proposing solutions to environmental problems.

Air and water

Clean Air Act. Clean Water Act. Safe Drinking Water Act.

Waste and toxics

Resource Conservation and Recovery Act (RCRA). Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the superfund law. The Delaney Clause of the Food, Drug, and Cosmetic Act.

Species and international agreements

Endangered Species Act. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Montreal Protocol. Kyoto Protocol.

Where students lose the most points

Most lost marks come from being too general. Graders want a named example and the mechanism behind it. On the calculation question they want your working, with units. “Pollution is bad for animals” earns nothing; “mercury biomagnifies up the food chain, harming top predators” earns the point. Our FRQ guide breaks down how each free-response question is scored.

How to use this in your last week

Take one unit at a time. Read its row, then answer a few multiple-choice questions and one free-response question from that unit. Mark yourself hard: if you did not name something specific, you would not have got the point.

Close the gaps with the Progress Check walkthroughs, keep the formula sheet nearby for the calculations, and check a practice raw score with the AP Enviro score calculator. If the exam still worries you, the numbers are friendlier than the reputation: our guide to whether is AP Environmental Science hard has the current score data.

Frequently asked questions

Quick answers, checked against College Board.

Can I bring a cheat sheet into the AP Environmental Science exam?

No. AP Environmental Science is a fully digital exam taken in the Bluebook app, so there are no notes to bring and no booklet to hand back. A calculator is allowed on both sections, and Bluebook has a Desmos scientific calculator built in. If you bring your own, note that from the 2027 exam handheld calculators with storage, including graphing calculators, are not allowed. Use a cheat sheet like this one in the week before, not on the day.

Does the AP Environmental Science exam give you a formula sheet?

Not the way AP Biology, Chemistry and Physics do. Those exams have published equation sheets and reference tables. College Board has never published one for AP Environmental Science, and it is not in the course and exam description. There is reference information inside Bluebook, but its contents are unpublished, so plan on knowing the equations yourself.

How much time do I get for each APES free-response question?

Section II is 70 minutes for three questions, and College Board suggests about 22 minutes each. All three are worth 10 points, so none of them is worth overspending on.

Is the Paris Agreement on the APES required legislation list?

No. College Board lists ten required policies and the international ones stop at the Kyoto Protocol. NEPA is not on the list either, although several study sites include both.

Which APES units should I revise first if I am short on time?

Unit 9, Global Change, is the single heaviest at 15–20%. Populations, Earth Systems and Resources, Land and Water Use, and Energy are each 10–15%, so together they can reach 60% of the multiple choice. Units 1 and 2 are 6–8% each and are the cheapest to skim.

Is AP Environmental Science hard?

Its reputation comes from an era that has ended. In 2026, 69% of students scored a 3 or higher and 13% earned a 5, up from 54% as recently as 2024. The content is broad rather than deep, which is why vague answers cost more marks than difficulty does.