AP Environmental Science - Unit 1: The Living World

Vocabulary practice flashcards covering biomes, biogeochemical cycles, ecological relationships, thermodynamic principles, and ecosystem dynamics from AP Environmental Science Unit 1.

Hot Desert

A biome containing plants adapted to prevent water loss due to low average rainfall and high temperatures year-round.

Flux

The rate at which materials move between the areas they are stored in; may be affected by human activities.

First Law of Thermodynamics

A physical law stating that all energy is neither created nor destroyed.

Second Law of Thermodynamics

A physical law stating that in an energy conversion, some energy will be lost to the environment.

Producer

An organism that serves as the basis of every food chain or food web.

Tropical Rainforest

The most diverse yet most threatened terrestrial biome, situated at the equator and characterized by hot temperatures, heavy precipitation, poor soil nutrients, broadleaf evergreen trees, primates, and poison dart frogs.

Parasitism

A symbiotic interaction in which one organism benefits while harming the host, exemplified by intestinal hookworms feeding on a human.

Commensalism

A relationship between two organisms where one benefits and the other is unaffected, exemplified by cattle egrets feeding on insects stirred up by foraging cattle.

Scientific Law

A well-tested and widely accepted description of what we find happening repeatedly and in the same way in nature.

Model

An approximate representation or simulation of a system.

Boreal Forest

Forests with cold, dry winters and short, cool, wet summers; primarily alpine and characterized by thick growth of coniferous trees, sheltering over $85$ mammal species such as wood bison, elk, moose, woodland caribou, and grizzly bears.

Denitrification

The nitrogen cycle process where nitrate ions and nitrite ions are converted to nitrous oxide gas and nitrogen gas ($N_2$).

Nitrogen Fixation

The process by which nitrogen gas is converted into ammonium by bacteria in the soil or cyanobacteria in aquatic ecosystems.

Assimilation

The process where plant roots absorb ammonium ions and nitrate ions to synthesize molecules such as DNA, amino acids, and proteins.

Nitrification

The chemical process in which ammonia is converted into nitrite ($NO_2$) and subsequently into nitrate ($NO_3$).

The Sun

The ultimate source of energy for ecological systems.

Formation of Carbonate Deposits

A geochemical process that indirectly removes carbon from Earth's atmosphere.

Cyanobacteria

Aquatic microorganisms that fix atmospheric nitrogen into ammonium.

Rhizobium

A genus of nitrogen-fixing bacteria that lives symbiotically within the roots of legumes.

Eutrophication

The progressive enrichment of an entire body of water (or portions of it) with minerals and nutrients such as nitrogen and phosphorus.

Photosynthesis

A process occurring in plants and microbes that converts carbon dioxide, water, and energy into sugars and oxygen.

Aquifer

A porous underground rock formation that allows groundwater to flow through it.

Watershed

An area of land where precipitation falls and drains into a common river or body of water.

Phosphorus Cycle

A biogeochemical cycle that lacks an atmospheric gaseous phase; its main reservoir is rocks, and its initial extraction occurs through weathering.

Lightning

An atmospheric event providing the electrical energy needed to convert nitrogen gas, allowing it to enter ecosystems via rainfall.

Decomposition

The biological breakdown of dead organic matter by fungi and bacteria into carbon dioxide, recycling nutrients back into their cycles.

Hydrologic Cycle

The global biogeochemical system of water movement, whose largest reservoir is the oceans.

Taiga

A cold and wet biome situated between $50^\text{o}\text{--}60^\text{o}\text{ N}$ latitudes, dominated by perennials, conifer trees, moose, wolves, and bears.

Temperate Grassland

A biome found at $30^\text{o}\text{--}40^\text{o}\text{ N}$ characterized by hot, dry summers and cold, wet winters, supporting grasses, scattered trees, bison, prairie dogs, and ferrets.

Chaparral

A warm and moderate biome located around $30^\text{o}\text{ N and S}$, dominated by drought-resistant small shrubs, reptiles, coyotes, and squirrels.

Savanna

A warm and wet biome featuring broadleaf grasses, zebras, lions, and elephants, located in coastal or midlatitude transition zones.

Temperate Deciduous Forest

A warm and wet transitional biome characterized by deciduous trees, flowers, deer, chipmunks, squirrels, and songbirds.

Tundra

A polar desert biome located north of $60^\text{o}\text{ N}$ and near the poles, characterized by permafrost, low precipitation, lichen, mosses, caribou, and hares.

Tolerance

The range of environmental conditions (such as temperature or pH) within which an organism can survive and withstand, such as brook trout thriving in cold water within a specific temperature range.

Limiting Factor

Any resource or environmental condition that is in the shortest supply and restricts the growth of a population, such as phosphorus controlling algal populations in freshwater lakes.

Long-Term Stores

Reservoirs such as fossil fuels whose nutrient reintroduction by human activity produces a more disruptive ecological effect than short-term stores, which cycle rapidly through living organisms.