Environmental Science Exam Prep

AP Environmental Science study planner for May 2027

Unit 9 carries 15–20% of the multiple choice, Units 3 to 6 10–15% each, Units 7 and 8 7–10% and Units 1 and 2 6–8%. Tell the planner how sure you are of each unit and it spends your time where the points are.

Hours a week for AP Environmental Science
Unit 1: The Living World: Ecosystems 6–8%
Unit 2: The Living World: Biodiversity 6–8%
Unit 3: Populations 10–15%
Unit 4: Earth Systems and Resources 10–15%
Unit 5: Land and Water Use 10–15%
Unit 6: Energy Resources and Consumption 10–15%
Unit 7: Atmospheric Pollution 7–10%
Unit 8: Aquatic and Terrestrial Pollution 7–10%
Unit 9: Global Change 15–20%

30 weeks to the exam on May 13, 2027

Start with Unit 9

Unit 9: Global Change: 19.9 of your 120 hours. It carries 15–20% of the multiple choice, about 14 of the 80 questions.

Hours per unit
UnitHoursAbout this many questions
Unit 9: Global Change19.914 of 80
Unit 3: Populations14.210 of 80
Unit 4: Earth Systems and Resources14.210 of 80
Unit 5: Land and Water Use14.210 of 80
Unit 6: Energy Resources and Consumption14.210 of 80
Unit 7: Atmospheric Pollution9.77 of 80
Unit 8: Aquatic and Terrestrial Pollution9.77 of 80
Unit 1: The Living World: Ecosystems86 of 80
Unit 2: The Living World: Biodiversity86 of 80

Week by week

  1. Week 1 · Oct 13Unit 9: Global Change
  2. Week 2 · Oct 20Unit 9: Global Change
  3. Week 3 · Oct 27Unit 9: Global Change
  4. Week 4 · Nov 3Unit 9: Global Change
  5. Week 5 · Nov 10Unit 9: Global Change, Unit 3: Populations
  6. Week 6 · Nov 17Unit 3: Populations
  7. Week 7 · Nov 24Unit 3: Populations
  8. Week 8 · Dec 1Unit 3: Populations
  9. Week 9 · Dec 8Unit 3: Populations, Unit 4: Earth Systems and Resources
  10. Week 10 · Dec 15Unit 4: Earth Systems and Resources
  11. Week 11 · Dec 22Unit 4: Earth Systems and Resources
  12. Week 12 · Dec 29Unit 4: Earth Systems and Resources
  13. Week 13 · Jan 5Unit 4: Earth Systems and Resources, Unit 5: Land and Water Use
  14. Week 14 · Jan 12Unit 5: Land and Water Use
  15. Week 15 · Jan 19Unit 5: Land and Water Use
  16. Week 16 · Jan 26Unit 5: Land and Water Use, Unit 6: Energy Resources and Consumption
  17. Week 17 · Feb 2Unit 6: Energy Resources and Consumption
  18. Week 18 · Feb 9Unit 6: Energy Resources and Consumption
  19. Week 19 · Feb 16Unit 6: Energy Resources and Consumption
  20. Week 20 · Feb 23Unit 6: Energy Resources and Consumption, Unit 7: Atmospheric Pollution
  21. Week 21 · Mar 2Unit 7: Atmospheric Pollution
  22. Week 22 · Mar 9Unit 7: Atmospheric Pollution, Unit 8: Aquatic and Terrestrial Pollution
  23. Week 23 · Mar 16Unit 8: Aquatic and Terrestrial Pollution
  24. Week 24 · Mar 23Unit 8: Aquatic and Terrestrial Pollution
  25. Week 25 · Mar 30Unit 8: Aquatic and Terrestrial Pollution, Unit 1: The Living World: Ecosystems
  26. Week 26 · Apr 6Unit 1: The Living World: Ecosystems
  27. Week 27 · Apr 13Unit 1: The Living World: Ecosystems, Unit 2: The Living World: Biodiversity
  28. Week 28 · Apr 20Unit 2: The Living World: Biodiversity
  29. Week 29 · Apr 27Timed practice exam, then review every miss
  30. Week 30 · May 4Timed practice exam, then review every miss

Check your units with the free diagnostic

ExamThursday, May 13, 2027
Unit 915–20% of the multiple choice
Units 3 to 610–15% each
Last weeksKept for timed practice exams

How the plan is made

  • Each unit starts from the middle of its published weight range.
  • A unit you have not started gets about one and a half times its share; a solid unit gets under half.
  • Units are ordered by need, and the final one or two weeks are timed practice exams with review of every miss.

Making the hours count

  • Start each unit with a few questions to find what you do not know, then the lesson, then more questions.
  • Do a few calculations every week: they appear in every unit and in the free response.
  • Answer one free-response question a week and check every point against its task verb.

Try 2 questions

Question 1
The diagram shows part of a food web along the Pacific coast. When hunters removed sea otters from parts of the coast, what happened to the kelp, and why?

Dissolved oxygen along River S

A sewage outfall empties into River S at 0 km. The graph shows dissolved oxygen measured along the river one afternoon in July; negative distances are upstream of the outfall.

Question 2
What best explains the drop in dissolved oxygen downstream of the outfall?

Next step

College Board's AP Environmental Science course page, with the unit weights

Questions people ask

Which AP Environmental Science unit is weighted most?

Unit 9, Global Change, at 15–20% of the multiple choice. Units 3 to 6 are 10–15% each.

How long should I study for AP Environmental Science?

It depends on how much of the course you know. The planner turns your weekly hours into hours per unit; steady weekly practice beats a final cram.

When should I start studying for the 2027 AP Environmental Science exam?

Now is best: steady weekly study through the school year leaves the final weeks for full practice exams before May 13, 2027.