AP Environmental Science: 300 Terms with Real Cases

The free-response marks go to the mechanism and the example, not to the definition alone.

300 cardsLast updated 2026-08-31

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Defining eutrophication earns nothing on its own. The point comes from saying that nutrient enrichment drives an algal bloom, that decomposing algae consume the oxygen, and that fish die in the resulting low-oxygen zone. Environmental science is a vocabulary course only on the surface. What it actually tests is whether you can name a cause, trace it to an effect, and attach a real case. This deck is 300 cards, one term per card, with the back giving the definition and, where it applies, a line on why it matters: what the term causes, prevents or explains. The sections follow the course: ecosystems and biodiversity, populations, earth systems and resources, land and water use, energy, and pollution and global change. No country's current statistic appears. Emissions figures and renewable shares change every year and a memorised number goes stale without warning, while the mechanism behind it does not. Once the deck is on a spaced-repetition schedule, the terms you can already explain stop coming back and the ones whose mechanism you keep reversing return until they stop being guesswork.

What happens when you add it

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What's inside

Showing 100 representative cards from the full 300-card deck.

Front	Back
Ecosystem — what is it?	A community of organisms together with the physical environment they interact with. It is the unit at which energy flow and nutrient cycling are studied.
Producer — what is it?	An organism that makes its own food from inorganic sources. Producers capture the energy that every other trophic level depends on.
Decomposer — what is it?	An organism that breaks down dead material into simpler compounds. Decomposition returns nutrients to the soil so that producers can reuse them.
Food web — what is it?	A network of interconnected food chains in a community. It shows how the loss of one species can affect many others.
Gross primary productivity — what is it?	The total rate at which producers capture energy. It sets the ceiling on how much energy can enter the ecosystem.
Carbon cycle — what is it?	The movement of carbon among the atmosphere, oceans, land and living things. Human interference with it is the main driver of climate change.
Nitrogen cycle — what is it?	The movement of nitrogen among the atmosphere, soil and organisms. Nitrogen availability limits plant growth in many ecosystems.
Denitrification — what is it?	The conversion of nitrates back into atmospheric nitrogen. It closes the nitrogen cycle and removes nitrogen from soils.
Water cycle — what is it?	The continuous movement of water through evaporation, condensation and precipitation. It redistributes fresh water and shapes the climate of every region.
Biome — what is it?	A large region defined by its climate and characteristic vegetation. Biomes explain why similar communities appear on different continents.
Temperate deciduous forest — what is it?	A biome with warm summers, cold winters and trees that shed their leaves. Its rich leaf litter builds fertile soils.
Desert — what is it?	A biome defined by very low precipitation. Slow recovery from disturbance makes desert soils easy to damage.
Aquatic life zones — what is it?	Divisions of water bodies based on depth, light and salinity. Light availability sets where photosynthesis is possible.
Ecological succession — what is it?	The gradual change in the species composition of a community over time. It explains how ecosystems recover after disturbance.
Secondary succession — what is it?	Succession on land where soil remains after a disturbance. It is much faster than primary succession because the seed bank survives.
Ecological niche — what is it?	The full role a species plays in its ecosystem. Species with identical niches cannot coexist indefinitely.
Specialist species — what is it?	A species with a narrow niche and specific requirements. Specialists are highly vulnerable to habitat change.
Resource partitioning — what is it?	The division of a shared resource so that competitors can coexist. It reduces direct competition and allows greater diversity.
Mutualism — what is it?	A symbiosis in which both species benefit. Mutualisms underpin many ecosystems, including pollination and nutrient uptake.
Keystone species — what is it?	A species whose effect on a community is far larger than its abundance suggests. Removing it causes disproportionate change throughout the ecosystem.
Biodiversity — what is it?	The variety of life at the genetic, species and ecosystem levels. Greater diversity generally increases resilience to disturbance.
Habitat fragmentation — what is it?	The division of a continuous habitat into smaller isolated patches. It reduces population sizes and blocks movement between them.
Island biogeography — what is it?	The theory relating species number on an island to its size and isolation. It guides how nature reserves are sized and connected.
Population — what is it?	A group of individuals of one species living in the same area. It is the level at which growth, density and limits are measured.
Population dispersion — what is it?	The spatial pattern in which individuals are arranged. The pattern reveals whether resources are patchy or individuals repel each other.
Exponential growth — what is it?	Growth in which population increases by a constant proportion each interval. It produces a J-shaped curve and cannot continue indefinitely.
Carrying capacity — what is it?	The largest population an environment can support indefinitely. Exceeding it damages the resource base and lowers it further.
Density-dependent factor — what is it?	A limiting factor whose effect strengthens as density rises. It stabilises populations near carrying capacity.
Biotic potential — what is it?	The maximum rate at which a population could grow under ideal conditions. It sets the upper bound that environmental resistance reduces.
r-selected species — what is it?	A species with many offspring, little parental care and a short life. These species colonise disturbed areas quickly.
Type one survivorship — what is it?	A pattern of low mortality until old age. It is typical of species with heavy parental care.
Demography — what is it?	The statistical study of human populations. It provides the data used to project future population size and needs.
Infant mortality rate — what is it?	The number of deaths of infants under one year per thousand live births. It is a sensitive indicator of health care and living conditions.
Demographic transition — what is it?	The shift from high birth and death rates to low ones as a country develops. It explains why population growth peaks partway through development.
Stage two of the demographic transition — what is it?	A stage where death rates fall but birth rates remain high. It produces the fastest population growth of any stage.
Age structure diagram — what is it?	A graph showing the number of people in each age group by sex. Its shape predicts future growth even when current rates are known.
Doubling time — what is it?	The time a population takes to double at a given growth rate. It makes small differences in growth rate easier to grasp.
Ecological footprint — what is it?	The area of productive land and water needed to support a person or population. It compares consumption against what the planet can regenerate.
IPAT equation — what is it?	A framework describing impact as population times affluence times technology. It shows that consumption per person matters as much as headcount.
Plate tectonics — what is it?	The theory that the Earth's outer shell is divided into moving plates. It explains the distribution of earthquakes, volcanoes and mountain ranges.
Convergent boundary — what is it?	A boundary where plates move toward each other. It produces subduction zones, deep trenches and explosive volcanoes.
Subduction — what is it?	The sinking of one plate beneath another. It recycles crust and drives volcanic arcs above the descending plate.
Earthquake — what is it?	Ground shaking caused by a sudden release of stress in the crust. Building codes and land-use planning determine how much damage results.
Weathering — what is it?	The physical and chemical breakdown of rock at the Earth's surface. It is the first step in soil formation and releases mineral nutrients.
Soil permeability — what is it?	The rate at which water moves through soil. It determines runoff, infiltration and the risk of waterlogging.
Layers of the atmosphere — what is it?	The vertical divisions of the atmosphere by temperature behaviour. Each layer has distinct effects on weather, ozone and radiation.
Ozone layer — what is it?	A region of the stratosphere with a high concentration of ozone. It shields the surface from harmful ultraviolet radiation.
Coriolis effect — what is it?	The apparent deflection of moving air and water caused by the Earth's rotation. It sets the direction of prevailing winds and ocean gyres.
Weather and climate — what is it?	Short-term atmospheric conditions and long-term average patterns. Confusing the two leads to misreading single events as trends.
Upwelling — what is it?	The rise of deep, nutrient-rich water toward the surface. It supports some of the world's most productive fisheries.
Watershed — what is it?	The land area that drains into a particular body of water. Everything that happens on that land affects the water quality downstream.
Aquifer depletion — what is it?	The withdrawal of groundwater faster than it is recharged. It causes wells to fail and the land surface to subside.
Surface water and groundwater — what is it?	Water in rivers and lakes and water stored beneath the ground. They are connected, so pumping one can reduce the other.
Floodplain — what is it?	The flat land beside a river that floods periodically. Building on it puts property in the path of predictable flooding.
Renewable resource — what is it?	A resource replenished on a human timescale. It remains available only if used no faster than it regenerates.
Industrial agriculture — what is it?	Large-scale farming using machinery, fertiliser and chemical inputs. It raises yields per hectare while increasing energy use and runoff.
Crop rotation — what is it?	Growing different crops in a field in successive seasons. It breaks pest cycles and restores soil nitrogen.
Soil salinisation — what is it?	The accumulation of salts in soil, usually from irrigation. It reduces yields and can make land unusable.
Pesticide — what is it?	A chemical used to kill organisms that damage crops. It raises short-term yields but harms non-target species and selects for resistance.
Biological pest control — what is it?	The use of natural enemies to suppress pests. It avoids chemical residues but can go wrong if the control agent spreads.
Biomagnification — what is it?	The increase in the concentration of a chemical at successive trophic levels. Top predators receive the highest doses.
Contour ploughing — what is it?	Ploughing across a slope rather than up and down it. It slows runoff and reduces soil loss.
Overfishing — what is it?	Harvesting fish faster than the population can reproduce. It reduces catches over time and can collapse a fishery entirely.
Clear-cutting — what is it?	Removing all trees from an area at once. It is cheap but causes erosion, habitat loss and stream warming.
Reforestation — what is it?	Replanting trees on land that was recently forested. It restores carbon storage and reduces erosion.
Surface mining — what is it?	Extracting minerals by removing the overlying soil and rock. It is cheaper than underground mining but destroys the surface entirely.
Acid mine drainage — what is it?	Acidic water flowing from mines when sulphide minerals are exposed. It kills aquatic life and mobilises toxic metals.
Urban sprawl — what is it?	Low-density expansion of a city into surrounding land. It consumes farmland, increases driving and raises infrastructure costs.
Smart growth — what is it?	Planning that concentrates development and preserves open space. It reduces sprawl and driving distances.
Ecological reserve — what is it?	An area set aside primarily to protect ecosystems and species. Reserve size and connectivity determine how much biodiversity survives.
Ecotourism — what is it?	Travel to natural areas managed to minimise impact and support conservation. It gives local communities an economic reason to protect habitat.
Fossil fuel — what is it?	A fuel formed from the buried remains of ancient organisms. Burning it releases carbon that had been stored underground for millions of years.
Natural gas — what is it?	A gaseous fossil fuel that is mostly methane. It emits less carbon dioxide per unit of energy than coal but leaks a potent greenhouse gas.
Cogeneration — what is it?	Using the waste heat from electricity generation for heating. It raises the overall efficiency of a fuel far above electricity alone.
Passive solar design — what is it?	Designing a building to use sunlight for heating and lighting without machinery. It cuts energy demand for the entire life of the building.
Nuclear fission — what is it?	The splitting of heavy atomic nuclei to release energy. It generates large amounts of electricity with almost no carbon dioxide.
Half-life — what is it?	The time for half of a radioactive sample to decay. It determines how long waste must be isolated.
Hydroelectric power — what is it?	Electricity generated from flowing or falling water. It provides reliable low-carbon power but alters river ecosystems.
Solar photovoltaic — what is it?	Technology that converts sunlight directly into electricity. It has no emissions in operation and can be installed at any scale.
Wind power — what is it?	Electricity generated by turbines driven by moving air. It has low operating emissions and land beneath turbines stays usable.
Geothermal energy — what is it?	Energy drawn from heat within the Earth. It provides steady output but is limited to areas with accessible heat.
Biomass energy — what is it?	Energy from burning or processing organic material. It can be near carbon neutral if the material is regrown.
Hydrogen fuel — what is it?	A fuel that releases only water when burned or used in a fuel cell. Its emissions depend entirely on how the hydrogen was produced.
Pumped storage — what is it?	Storing energy by pumping water uphill and releasing it later. It is the largest-scale storage method currently in use.
Point source pollution — what is it?	Pollution entering the environment from a single identifiable place. It is easier to regulate because the source can be measured directly.
Primary pollutant — what is it?	A pollutant released directly into the air from a source. It can be reduced by controlling emissions at the source.
Sulphur dioxide — what is it?	A gas released mainly by burning sulphur-containing fuels. It irritates airways and forms acid deposition downwind.
Volatile organic compounds — what is it?	Carbon-based chemicals that evaporate easily at room temperature. They react with nitrogen oxides in sunlight to form ozone.
Industrial smog — what is it?	A grey haze of sulphur compounds and particulates from coal burning. It is associated with cold, damp conditions rather than sunlight.
Acid deposition — what is it?	The fall of acidic compounds from the atmosphere as rain, snow or dry particles. It acidifies lakes and soils and damages forests and buildings.
Indoor air pollution — what is it?	Contamination of the air inside buildings. People spend most of their time indoors, so exposure can exceed outdoor levels.
Formaldehyde — what is it?	A volatile chemical released from some building materials and furnishings. It irritates eyes and airways and is classified as a carcinogen.
Eutrophication — what is it?	Nutrient enrichment of a water body that triggers excessive algal growth. Decomposing algae consume oxygen and kill aquatic life.
Thermal pollution of water — what is it?	The raising of water temperature by human activity. Warmer water holds less oxygen and stresses cold-adapted species.
Primary wastewater treatment — what is it?	The physical removal of solids from sewage. Screening and settling remove large material and suspended solids.
Sanitary landfill — what is it?	An engineered site for burying solid waste. Liners and leachate collection are meant to protect groundwater.
Waste reduction hierarchy — what is it?	The ranking of waste strategies from most to least preferred. Reducing comes before reusing, which comes before recycling and disposal.
Dose-response relationship — what is it?	The relationship between the amount of a substance and the effect observed. It underlies every risk assessment and exposure limit.
Ozone depletion — what is it?	The thinning of the stratospheric ozone layer. It allows more ultraviolet radiation to reach the surface.
Climate feedback — what is it?	A process that amplifies or dampens an initial climate change. Positive feedbacks make warming accelerate beyond the original cause.

Frequently asked

What is in each section of the deck?

Ecosystems and biodiversity has 55 cards, populations 40, earth systems and resources 50, land and water use 55, energy 45, and pollution and global change 55, for 300 in total. Every card carries section and subtopic tags, so you can drill only the energy unit or only the pollution unit.

Why are there no current statistics on the cards?

Because they go out of date faster than the deck does, and a wrong number is worse than no number. Emissions totals, energy shares and population figures all shift yearly. What does not shift is why a thermal inversion traps pollutants or why a dead zone forms, and that is what the cards carry.

Does it cover the maths on the exam?

It covers the concepts the calculations are built on, such as what a doubling time means or how energy is lost between trophic levels, but not the arithmetic itself. The exam's calculations are simple once the setup is right, and getting the setup right is what these cards support.

Can I import the whole deck on the free plan?

Yes. Importing a saved deck runs no new AI generation and does not use your AI allowance, so the free plan imports all 300 cards. You can study, edit and delete them afterwards.

Will importing it twice create duplicates?

No. Cards you already have are skipped and only cards added in a revision come through. Including re-imports after deleting it, one official deck can be imported three times per account.

Can I use it on the web and in the mobile app?

Yes. The deck is added to your account rather than to a device, so the same cards and the same progress are there on the web, on iOS and on Android.

Can I edit the cards after importing?

Yes. Imported cards are yours: you can edit both sides, delete cards you do not need, change tags, and move cards to another deck.