AP Environmental Science

Units and exam weighting

1. Unit 1: The Living World: Ecosystems 6–8% of the exam
   Ecosystem structure, biomes, carbon, nitrogen, phosphorus and water cycles, primary productivity, trophic levels, energy flow and food webs.
2. Unit 2: The Living World: Biodiversity 6–8% of the exam
   Biodiversity, ecosystem services, island biogeography, ecological tolerance, natural disruptions, adaptation, succession.
3. Unit 3: Populations 10–15% of the exam
   Generalist and specialist species, K- and r-selected species, survivorship curves, carrying capacity, population growth, age structure, human population dynamics.
4. Unit 4: Earth Systems and Resources 10–15% of the exam
   Plate tectonics, soil formation and composition, the atmosphere, global wind patterns, watersheds, solar radiation and seasons, El Niño and La Niña.
5. Unit 5: Land and Water Use 10–15% of the exam
   Tragedy of the commons, agriculture and irrigation, pest control, meat production, fishing, mining, urbanisation, ecological footprints, sustainability, aquaculture, forestry.
6. Unit 6: Energy Resources and Consumption 10–15% of the exam
   Renewable and non-renewable resources, global energy use, fossil fuels, nuclear power, biomass, solar, hydroelectric, geothermal, wind, energy conservation.
7. Unit 7: Atmospheric Pollution 7–10% of the exam
   Air pollutants, photochemical smog, thermal inversion, indoor air pollution, pollution reduction, acid rain, noise pollution.
8. Unit 8: Aquatic and Terrestrial Pollution 7–10% of the exam
   Sources of pollution, human impacts on ecosystems, endocrine disruptors, thermal pollution, solid waste, sewage treatment, LD50 and dose-response, pathogens.
9. Unit 9: Global Change 15–20% of the exam
   Stratospheric ozone, the greenhouse effect, global climate change, ocean warming and acidification, invasive species, endangered species, human impacts on biodiversity.