Environmental Science & Ecosystems Vocabulary

Comprehensive vocabulary flashcards covering species interactions, biomes, biogeochemical cycles, hydrologic cycle, primary productivity, energy flow, trophic dynamics, and food webs.

Resource availability

Amount of food, water, space or nutrients available; limits population growth and competition.

Competition

Organisms compete when they need the same limited resource.

Predator-prey relationship

One organism hunts and eats another; their populations often rise and fall together.

Producer (autotroph)

Makes organic food from sunlight or inorganic chemicals.

Consumer (heterotroph)

Gets energy by eating other organisms.

Decomposer

Breaks down dead matter and waste, recycling nutrients.

Symbiosis

Close, long-term relationship between different species.

Commensalism (+/0)

One benefits; the other is unaffected.

Mutualism (+/+)

Both species benefit.

Parasitism (+/−)

Parasite benefits while harming its host.

Climate

Long-term patterns of temperature and precipitation.

Geography

Physical location and features that influence environmental conditions.

Latitude

Distance north or south of the equator; influences sunlight and climate.

Altitude

Height above sea level; higher elevations are generally colder.

Biome

Large ecosystem defined by its climate and typical organisms.

Taiga (boreal forest)

Subarctic conifer forest with long, cold winters and low biodiversity.

Temperate rainforest

Coastal biome with mild temperatures, heavy rainfall and large trees.

Temperate seasonal forest (deciduous forest)

Midlatitude forest with four seasons, moderate precipitation and trees that lose their leaves.

Tropical rainforest

Warm, wet equatorial forest with high productivity and biodiversity but nutrient-poor soil.

Shrubland (chaparral)

Hot, dry summers and mild, wet winters; dominated by fire-adapted shrubs.

Temperate grassland

Midlatitude grass biome with seasonal temperatures, fertile soil, fire and grazing.

Savanna (tropical grassland)

Warm grassland with scattered trees and distinct wet and dry seasons.

Desert

Biome with very low precipitation, sparse vegetation and low productivity.

Tundra

Cold, dry biome with permafrost, low plants and a short growing season.

Permafrost

Permanently frozen soil beneath the surface.

Aquatic biome

Water-based ecosystem shaped by salinity, depth, flow and nutrient availability.

Freshwater biome

Aquatic ecosystem with very low salinity.

Stream

Small, flowing freshwater ecosystem.

River

Large, flowing freshwater ecosystem that carries water and sediment downstream.

Lake

Large body of standing freshwater divided into light and depth zones.

Pond

Small, shallow body of standing freshwater where light often reaches the bottom.

Marine biome

Saltwater ecosystem with an average salinity of about $3.5\%$.

Open ocean

Deep marine water away from shore; generally nutrient-poor except near upwellings.

Coral reef

Warm, shallow, clear marine ecosystem with extremely high biodiversity.

Marshland

Wetland dominated by grasses; filters water and reduces flooding.

Estuary

Nutrient-rich coastal area where freshwater mixes with saltwater.

Brackish water

Water containing a mixture of fresh and salt water.

Algae

Photosynthetic aquatic organisms that act as producers.

Plankton

Small organisms that drift with water currents.

Phytoplankton

Photosynthetic plankton; major aquatic producers.

Zooplankton

Animal-like plankton that consume other organisms.

Salinity

Concentration of dissolved salts in water.

Turbidity

Water cloudiness caused by suspended particles; reduces light penetration.

Photic zone

Upper water layer receiving enough light for photosynthesis.

Aphotic zone

Deep water receiving too little light for photosynthesis.

Benthic zone

Bottom surface of an aquatic ecosystem.

Carbon cycle

Movement of carbon among organisms, atmosphere, water, soil and rock.

Photosynthesis

Producers use sunlight to convert $CO_2$ and water into glucose and oxygen.

Cellular respiration

Organisms break down glucose with oxygen, releasing energy, $CO_2$ and water.

Carbohydrate

Energy-rich organic molecule made of carbon, hydrogen and oxygen.

Decomposition

Breakdown of dead matter that returns carbon to soil and atmosphere.

Combustion

Burning material, releasing stored carbon mainly as $CO_2$.

Fossil-fuel combustion

Burning coal, oil or natural gas, moving ancient carbon into the atmosphere.

Carbon dioxide (CO₂)

Greenhouse gas released by respiration, decomposition and combustion.

Carbon monoxide (CO)

Toxic gas produced by incomplete combustion.

Carbon reservoir

Place where carbon is stored.

Carbon sink

Reservoir that absorbs more carbon than it releases.

Organic matter

Carbon-containing material from living or once-living organisms.

Fossil fuels

Coal, oil and natural gas containing ancient stored carbon.

Limestone

Carbon-rich sedimentary rock and a major long-term carbon reservoir.

Ocean carbon sink

Ocean absorption and storage of atmospheric $CO_2$.

Nitrogen cycle

Movement and conversion of nitrogen among the atmosphere, soil and organisms.

Atmospheric nitrogen (N₂)

Largest nitrogen reservoir; about $78\%$ of the atmosphere.

Nitrogen fixation

Conversion of $N_2$ into ammonia/ammonium usable by plants.

Nitrogen-fixing bacteria

Bacteria that convert atmospheric $N_2$ into ammonia.

Ammonia (NH₃)

Nitrogen compound produced by fixation and decomposition.

Ammonium (NH₄⁺)

Soil nitrogen ion that plants can absorb.

Ammonification

Decomposers convert organic nitrogen into ammonia or ammonium.

Nitrification

Bacteria convert ammonium into nitrite and then nitrate.

Nitrite (NO₂⁻)

Intermediate nitrogen compound produced during nitrification.

Nitrate (NO₃⁻)

Plant-available nitrogen produced through nitrification.

Assimilation

Plants absorb inorganic nitrogen and build it into organic molecules.

Denitrification

Bacteria convert nitrate back into atmospheric $N_2$.

Nitrogen oxides (NOₓ)

Pollutant gases produced during combustion; contribute to smog and acid deposition.

Nitrogen reservoir

Location where nitrogen is stored, especially the atmosphere.

Phosphorus cycle

Movement of phosphorus through rock, soil, water and organisms; has no major atmospheric phase.

Weathering

Breakdown of rock that releases phosphate into soil and water.

Phosphate (PO₄³⁻)

Plant-available form of phosphorus.

Sedimentary rock

Main long-term reservoir of phosphorus.

Food-chain transfer

Consumers obtain phosphorus by eating plants or other animals.

Biological importance of phosphorus

Component of DNA, ATP, bones and cell membranes.

Limiting factor

Resource whose scarcity restricts population or ecosystem growth.

Phosphorus limitation

Phosphorus often limits productivity in freshwater ecosystems.

Fertilizer

Added plant nutrients, commonly nitrogen, phosphorus and potassium.

Fertilizer runoff

Nutrients washed into water, potentially causing excessive algal growth.

Hydrologic cycle (water cycle)

Continuous movement of water among Earth’s surface, atmosphere and groundwater.

Solar energy

Powers evaporation and drives the water cycle.

Evaporation

Liquid water changes into water vapor.

Transpiration

Plants release water vapor through their leaves.

Condensation

Water vapor cools into liquid droplets, forming clouds.

Precipitation

Water falls from the atmosphere as rain, snow, sleet or hail.

Runoff

Water flows across land into bodies of water.

Infiltration

Water enters the soil from the surface.

Percolation

Water moves downward through soil and rock.

Groundwater

Water stored underground in soil and rock spaces.

Aquifer

Permeable underground rock or sediment that stores groundwater.

Water reservoir

Place where water is stored.

Ocean

Earth’s largest water reservoir.

Ice caps and glaciers

Largest reservoir of Earth’s freshwater.

Groundwater reservoir

Largest available source of liquid freshwater.