APES Unit 1:The Living World

Ecosystem

All living organisms and nonliving components interacting in an area.

Biotic factor

A living or once-living part of an ecosystem.

Abiotic factor

A nonliving physical or chemical part of an ecosystem.

Population

All individuals of the same species living in an area.

Community

All populations of different species living and interacting in an area.

Biome

A large region characterized by its climate and typical plants and animals.

Climate

Long-term patterns of temperature and precipitation.

Tropical rainforest

Warm, wet biome with high biodiversity and productivity.

Temperate seasonal forest

Biome with seasonal temperatures, moderate precipitation, and deciduous trees.

Boreal forest (taiga)

Cold forest biome dominated by coniferous trees.

Grassland

Biome dominated by grasses with moderate precipitation.

Desert

Dry biome with very low precipitation.

Tundra

Cold, treeless biome with a short growing season and often permafrost.

Salinity

Concentration of dissolved salts in water.

Freshwater

Aquatic environment with very little dissolved salt.

Marine

Saltwater environment such as an ocean or sea.

Wetland

Land saturated with water for at least part of the year.

Estuary

Coastal area where freshwater mixes with saltwater.

Coral reef

Highly diverse marine ecosystem formed by corals.

Carbon cycle

Movement of carbon among the atmosphere, organisms, oceans, soil, and rocks.

Photosynthesis

Producers use sunlight to convert CO₂ and water into glucose and oxygen.

Cellular respiration

Organisms break down glucose for energy and release CO₂.

Combustion

Burning fuels or organic matter, releasing CO₂ into the atmosphere.

Carbon sink

Reservoir that absorbs more carbon than it releases.

Nitrogen fixation

Conversion of atmospheric nitrogen (N₂) into ammonia/ammonium.

Nitrification

Conversion of ammonia/ammonium into nitrite and then nitrate.

Assimilation

Uptake of nitrogen compounds by plants.

Ammonification

Conversion of organic nitrogen from wastes and dead organisms into ammonia/ammonium.

Denitrification

Conversion of nitrate into nitrogen gas, returning nitrogen to the atmosphere.

Phosphorus cycle

Movement of phosphorus among rocks, soil, water, and organisms.

Weathering

Breakdown of rock that releases phosphate into soil and water.

Phosphate

Form of phosphorus that can be taken up by organisms.

Limiting nutrient

A nutrient in short supply that restricts biological productivity.

Hydrologic cycle

Continuous movement of water through Earth's systems.

Evaporation

Conversion of liquid water into water vapor.

Transpiration

Release of water vapor from plants.

Precipitation

Water falling from the atmosphere to Earth's surface.

Infiltration

Movement of water from the surface into the soil.

Runoff

Water flowing over Earth's surface into waterways.

Aquifer

Underground layer of rock or sediment that stores groundwater.

Primary productivity

Rate at which producers convert solar energy into stored chemical energy.

Gross primary productivity (GPP)

Total energy captured by producers through photosynthesis.

Net primary productivity (NPP)

Energy remaining after producers use energy for respiration. Formula:GPP − respiration

Biomass

Total mass of living material in an area or trophic level.

Trophic level

An organism's feeding position in a food chain or food web.

Producer

Organism that makes its own food.

Primary consumer

Organism that eats producers.

Secondary consumer

Organism that eats primary consumers.

Decomposer

Organism that breaks down dead material and recycles nutrients.

10% rule

About 10% of the energy at one trophic level is available to the next trophic level.

Ecological efficiency

Percentage of energy transferred between trophic levels.

Energy pyramid

Diagram showing that available energy decreases at higher trophic levels.

Heat loss

Energy released to the environment as heat during metabolism.

Food chain

A single pathway showing energy transfer between organisms.

Food web

A network of interconnected food chains.

Predator

An organism that hunts and consumes another organism.

Prey

Organism that is hunted and consumed.

Energy flow

One-way movement of energy through an ecosystem.