Friedland, Environmental Science for AP® Course, Units 1-4

Upwelling

The upward movement of ocean water toward the surface as a result of diverging currents.

Rock cycle

The geologic cycle governing the constant formation, alteration, and destruction of rock material that results from tectonics, weathering, and erosion, among other processes.

Collision zone

An area where two continental plates are pushed together and the colliding forces push up the crust to form a mountain range.

C horizon

The least-weathered soil horizon, which always occurs beneath the B horizon and is similar to the parent material.

B horizon

Commonly known as subsoil, a soil horizon is composed primarily of mineral material with very little organic matter.

Lithosphere

The outermost layer of Earth, including the solid upper mantle and crust.

Acid precipitation (Acid rain)

Precipitation high in sulfuric acid and nitric acid.

Ozone

A pale blue gas composed of molecules made up of three oxygen atoms (O3).

Aqueducts

Pipes and canals that move water from where it is abundant to areas where it is scarce.

Island arc

A chain of islands formed by volcanoes as a result of two tectonic plates coming together and experiencing subduction.

Mesosphere

The layer of the atmosphere above the stratosphere, extending roughly 50 to 85 km (31-53 miles) above the surface of Earth.

Base saturation

The proportion of soil bases to soil acids, expressed as a percentage.

Ferrell cell

A convection current in the atmosphere that lies between Hadley cells and polar cells.

Water holding capacity

The amount of water a soil can hold against the draining force of gravity.

Coriolis effect

The deflection of an object's path due to the rotation of Earth.

La Niña

Following an El Niño event, trade winds in the South Pacific reverse strongly, causing regions that were hot and dry to become cooler and wetter.

Troposphere

A layer of the atmosphere closest to the surface of Earth, extending up to approximately 16 km (10 miles).

Core

The innermost zone of Earth's interior, composed mostly of iron and nickel. It includes a liquid outer layer and a solid inner layer.

Intertropical convergence zone (ITCZ)

The latitude that receives the most intense sunlight, which causes the ascending branches of the two Hadley cells to converge.

O horizon

The organic horizon at the surface of many soils, composed of organic detritus in various stages of decomposition.

Magma

Molten rock.

Porosity

The size of the air spaces between particles.

Chemical weathering

The breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both these processes.

Thermohaline circulation

An oceanic circulation pattern that drives the mixing of surface water and deep water.

Volcano

A vent in the surface of Earth that emits ash, gases, or molten lava.

Humus

The most fully decomposed organic matter in the lowest section of the O horizon.

Seafloor spreading

Caused by a divergent boundary, in which rising magma forms new ocean crust on the seafloor at the boundaries between those plates.

Watershed

All land in a given landscape that drains into a particular stream, river, lake, or wetland.

Tsunami

A series of waves in the ocean caused by seismic activity or an undersea volcano that causes a massive displacement of water.

Cation exchange capacity (CEC)

The ability of a particular soil to adsorb and release cations.

Carbon sequestration

The capture and long-term storage of carbon dioxide from the atmosphere.

A horizon (Topsoil)

Frequently the top layer of soil, a zone of organic material and minerals that have been mixed together.

Polar cell

A convection current in the atmosphere, formed by air that rises at 60° N and 60° S and sinks at the poles, 90° N and 90° S.

Thermosphere

The layer of the atmosphere above the mesosphere, extending 85 to 600 km (53-375 miles) above the surface of Earth.

Adiabatic heating

The heating effect of increased pressure on air as it sinks toward the surface of Earth and decreases in volume.

Plate tectonics

The theory that the lithosphere of Earth is divided into plates, most of which are in constant motion.

Albedo

The percentage of incoming sunlight reflected from a surface.

Exosphere

The outermost layer of the atmosphere which extends from 600 to 10,000 km (375-6,200 miles) above the surface of Earth.

Divergent boundary

An area below the ocean where tectonic plates move away from each other.

Insolation

Incoming solar radiation, which is the main source of energy on Earth.

Transform boundary

An area where tectonic plates move sideways past each other.

Subduction

The process in which the edge of an oceanic plate moves downward beneath the continental plate and is pushed toward the center of Earth.

Hot spot

In geology, a place where molten material from Earth's mantle reaches the lithosphere.

Asthenosphere

The layer of Earth located in the outer part of the mantle, composed of semi-molten rock.

Adiabatic cooling

The cooling effect of reduced pressure on air as it rises higher in the atmosphere and expands.

Hadley cell

A convection current in the atmosphere that cycles between the equator and 30° N and 30° S.

Convergent boundary

An area where one plate moves toward another plate and collides.

Fault

A fracture in rock caused by a movement of Earth's crust.

E horizon

A zone of leaching, or eluviation, found in some acidic soils under the O horizon or, less often, the A horizon.

Permeability

The ability of water to move through the soil.

Igneous rock

Rock formed directly from magma.

Sedimentary rock

Rock that forms when sediments such as muds, sands, or gravels are compressed by overlying sediments.

Saturation point

The maximum amount of water vapor in the air at a given temperature.

Gyre

A large-scale pattern of water circulation that moves clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Erosion

The physical removal of rock fragments from a landscape or ecosystem.

Mantle

The layer of Earth above the core, containing magma, the asthenosphere, and the solid upper mantle.

Physical weathering

The mechanical breakdown of rocks and minerals.

Latent heat release

The release of energy when water vapor in the atmosphere condenses into liquid water.

Parent material

The underlying rock material from which the inorganic components of a soil are derived.

Atmospheric convection current

Global patterns of air movement that are initiated by the unequal heating of Earth.

Stratosphere

The layer of the atmosphere above the troposphere, extending roughly 16 to 50 km (10-31 miles) above the surface of Earth.

Rain shadow

A region with dry conditions found on the leeward side of a mountain range as a result of humid winds from the ocean causing precipitation on the windward side.

Metamorphic rock

Rock that forms when sedimentary rock, igneous rock, or other metamorphic rock is subjected to high temperature and pressure.

Earthquake

A sudden movement of Earth's crust caused by a release of potential energy from the movement of tectonic plates.

Horizon

A horizontal layer in a soil defined by distinctive physical features such as color and texture.

El Niño-Southern Oscillation (ENSO)

A reversal of wind and water currents in the South Pacific.

Abiotic

Nonliving.

Accuracy

How close a measured value is to the actual or true value.

Biotic

Living.

Control group

In a scientific investigation, a group that experiences exactly the same conditions as the experimental group, except for the single variable under study.

Deductive reasoning

The process of applying a general statement to specific facts or situations.

Dependent variable

A variable that is dependent on other factors.

Ecosystem

A particular location on Earth with interacting biotic and abiotic components.

Environment

The sum of all the conditions surrounding us that influence life.

Environmental science

The field of study that looks at interactions among human systems and those found in nature.

Environmental studies

The field of study that includes environmental science and additional subjects such as environmental policy, economics, literature, and ethics.

Environmentalism

A social movement that seeks to protect the environment through lobbying, activism, and education.

First law of thermodynamics

A theory with no known exception that states that energy is neither created nor destroyed but it can change from one form to another.

Hypothesis

A testable conjecture about how something works.

Independent variable

A variable that is not dependent on other factors.

Inductive reasoning

The process of making general statements from specific facts or examples.

Natural experiment

A natural event that acts as an experimental treatment in an ecosystem.

Null hypothesis

A prediction that there is no difference between the groups or conditions that are being compared.

Precision

How close the repeated measurements of a sample are to one another.

Replication

The data collection procedure of taking repeated measurements.

Sample size (n)

The number of times a measurement is replicated in data collection.

Scientific method

An objective method to explore the natural world, draw inferences from it, and predict the outcome of certain events, processes, or changes.

Second law of thermodynamics

The physical law stating that when energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes.

Sustainability

Living on Earth in a way that allows humans to use its resources without depriving future generations of those resources.

Theory

A hypothesis that has been repeatedly tested and confirmed by multiple groups of researchers and has reached wide acceptance.

Uncertainty

An estimate of how much a measured or calculated value differs from a true value.

Variable

Any categories, conditions, factors, or traits that differ in the natural world or in experimental situations.

Aerobic

An environment with abundant oxygen.

Aerobic respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Algal bloom

A rapid increase in the algal population of a waterway.

Anaerobic

An environment that lacks oxygen.

Anaerobic respiration

The process by which cells convert glucose into energy in the absence of oxygen.

Aphotic zone

The deeper layer of ocean water that lacks sufficient sunlight for photosynthesis.

Aquatic biome

An aquatic region characterized by a particular combination of salinity, depth, and water flow.

Assimilation

A process by which plants and algae incorporate nitrogen into their tissues.