AP Environmental Science: Unit 1 & Global Change Review

Vocabulary practice flashcards covering AP Environmental Science topics including biogeochemical cycles, ecosystem ecology, biomes, energy transfers, and global change phenomena.

Turbidity

A water quality parameter indicating water cloudiness caused by suspended particulates.

Acidity

A water sample property measured on the pH scale that reflects the concentration of hydrogen ions.

Denitrification

The biological process in which soil nitrate ($\text{NO}_3^-$) is reduced by bacteria and released back to the atmosphere as nitrogen gas ($\text{N}_2$).

Nitrification

The multi-step conversion of ammonia or ammonium ($\text{NH}_4^+$) into nitrite ($\text{NO}_2^-$) and then into plant-accessible nitrate ($\text{NO}_3^-$) by soil bacteria.

Nitrogen Fixation

The conversion of atmospheric nitrogen ($\text{N}_2$) into biologically accessible ammonia ($\text{NH}_3$) or ammonium ($\text{NH}_4^+$), carried out by specialized bacteria in soil and root nodules or abiotic processes like lightning.

Chlorofluorocarbons (CFCs)

Potent greenhouse gases of exclusively anthropogenic origin that absorb thermal infrared radiation with high efficiency and deplete stratospheric ozone.

Gross Primary Productivity (GPP)

The total amount of solar energy captured by primary producers through photosynthesis over a given unit of time.

Net Primary Productivity (NPP)

The rate at which energy is stored as plant biomass after subtracting the energy consumed by producer respiration ($NPP = GPP - R$).

Second Law of Thermodynamics

The physical principle dictating that energy transformations increase entropy (disorder), resulting in the loss of usable energy as heat between successive trophic levels.

Permafrost

Underground soil that remains frozen for more than two consecutive years, acting as a major Arctic carbon store that releases methane and carbon dioxide upon thawing.

Albedo

The reflectivity of Earth's surface; when high-albedo polar snow and ice melt, exposed darker ground or water absorbs more heat, driving a positive climate feedback loop.

Ocean Acidification

The reduction in ocean pH caused by the absorption of anthropogenic atmospheric carbon dioxide ($\text{CO}_2$), which elevates hydrogen ion concentrations and limits carbonate availability for shell-building organisms.

Competitive Exclusion Principle

The ecological rule stating that two species competing for the exact same limiting resource cannot stably coexist, leading to the local extinction or suppression of the weaker competitor.

Resource Partitioning

The ecological strategy where competing species divide limited resources by utilizing different foraging zones, microhabitats, or times of activity to minimize direct competition.

Biomass Trophic Pyramid

A graphical model demonstrating the total dry weight of organisms across trophic levels, reflecting the typical 90% loss of usable biomass and energy from one tier to the next.

Carbon Sink

A natural or artificial reservoir that absorbs and stores carbon compounds from the atmosphere over long periods, such as deep-sea sediments, limestone rocks, and mature forests.

Phosphorus Cycle

A major sedimentary biogeochemical cycle whose largest reservoir is sedimentary rock; it lacks an atmospheric or gaseous phase under normal environmental conditions.

Mutualism

A symbiotic ecological relationship in which both participating species derive a fitness or survival benefit, such as bees pollinating flowers while gathering nectar.

Parasitism

An ecological relationship where one organism lives on or in a host organism to acquire nutrients, causing harm to the host's fitness, growth, or reproduction.

Commensalism

A type of symbiotic interaction in which one organism benefits while the other organism is neither positively nor negatively affected.

Intertidal Zone

The coastal ocean biome spanning the area between high and low tide, subjected to extreme daily fluctuations in water coverage, temperature, and sunlight.

Littoral Zone

The shallow, nutrient-rich nearshore zone of a lake or pond where sunlight penetrates to the bottom, supporting rooted emergent aquatic vegetation like cattails and rushes.

Abyssal Zone

The very deep, completely dark benthic layer of the ocean characterized by near-freezing temperatures, intense hydrostatic pressure, and an absence of photosynthetic producers.

Trophic Cascade

An indirect ecological interaction where the removal or reintroduction of a top predator (such as the gray wolf in Yellowstone) cascades downward to regulate prey populations and restructure lower trophic levels.

Tropical Rain Forest

A terrestrial biome found near the equator that receives warm temperatures and abundant rainfall year-round, resulting in the highest terrestrial net primary productivity and species diversity despite nutrient-poor soils.

Tundra

A cold, low-precipitation biome characterized by a permanently frozen subsoil layer (permafrost), short growing seasons, and treeless vegetation dominated by lichens, mosses, and dwarf shrubs.

Taiga (Boreal Forest)

A subarctic biome dominated by dense evergreen coniferous forests adapted to short, cool summers and long, harsh winters; Russia possesses the world's largest expanse.

Keeling Curve

A graph plotting atmospheric $\text{CO}_2$ concentration measured continuously at Mauna Loa Observatory since 1958, highlighting steady multi-decade increases due to fossil fuel combustion alongside annual seasonal photosynthetic oscillations.