APES test

Biosphere

The region of our planet where life resides; the combination of all ecosystems on Earth.

Producer

An organism that uses the energy of the Sun to produce usable forms of energy; also known as Autotroph.

Photosynthesis

The process by which producers use solar energy to convert carbon dioxide and water into glucose.

Cellular respiration

The process by which cells unlock the energy of chemical compounds.

Aerobic respiration

Respiration that requires oxygen and produces more energy.

Anaerobic respiration

Respiration that does not require oxygen.

Consumer

An organism that is incapable of photosynthesis and must obtain its energy by consuming other organisms; also known as Heterotroph.

Herbivore

A consumer that eats producers; also known as Primary consumer.

Carnivore

A consumer that eats other consumers.

Secondary consumer

A carnivore that eats primary consumers.

Tertiary consumer

A carnivore that eats secondary consumers.

Trophic levels

The successive levels of organisms consuming one another.

Food chain

The sequence of consumption from producers through tertiary consumers.

Food web

A complex model of how energy and matter move between trophic levels.

Scavenger

An organism that consumes dead animals.

Detritivore

An organism that specializes in breaking down dead tissues and waste products into smaller particles.

Decomposers

Fungi and bacteria that convert organic matter into small elements and molecules that can be recycled back into the ecosystem.

Gross primary productivity (GPP)

Total amount of solar energy that producers in an ecosystem capture via photosynthesis over a given time.

Net primary productivity (NPP)

The energy captured by producers in an ecosystem minus the energy producers respire.

Biomass

The total mass of all living matter in a specific area.

Ecological efficiency

The proportion of consumed energy that can be passed from one trophic level to another, often expressed as a rule of 10%.

Trophic pyramid

A representation of the distribution of biomass, numbers, or energy among trophic levels.

Transpiration

The release of water from leaves during photosynthesis.

Evapotranspiration

The combined amount of evaporation and transpiration.

Runoff

Water that moves across the land surface and into streams and rivers.

Human impacts

Factors such as withdrawal, overuse, dam construction, irrigation, deforestation, and urbanization that affect ecosystems.

Pollution

The introduction of contaminants into the natural environment that can cause harm.

Carbon cycle

The movement of carbon around the biosphere.

Sinks

Reservoirs where carbon is stored, such as oceans, rocks, and biomass.

Sources

Processes that release carbon, including emissions from combustion, deforestation, and respiration.

Nitrogen cycle

The movement of nitrogen around the biosphere.

Limiting nutrient

A nutrient required for the growth of an organism but available in lower quantity than other nutrients.

Nitrogen fixation

A process by which some organisms convert nitrogen gas molecules directly into ammonia.

Nitrification

The conversion of ammonia (NH₄⁺) into nitrite (NO₂⁻) and then into nitrate (NO₃⁻).

Assimilation

The process by which producers incorporate elements into their tissues.

Mineralization

The process by which decomposers break down organic matter into inorganic compounds.

Ammonification

The conversion of organic nitrogen in dead bodies and waste into inorganic ammonium (NH₄⁺) by decomposers.

Denitrification

The conversion of nitrate (NO₃⁻) into nitrogen gas (N₂) emitted into the atmosphere.

Leaching

The transportation of dissolved molecules through the soil via groundwater.

Phosphorus cycle

The movement of phosphorus around the biosphere.

Algal bloom

A rapid increase in the algal population of a waterway.

Hypoxic

Low in oxygen.

Sulfur cycle

The movement of sulfur around the biosphere.

Disturbance

An event causing changes in population size or community composition due to physical, chemical, or biological agents.

Resistance

A measure of how much a disturbance can affect flows of energy and matter in an ecosystem.

Resilience

The rate at which an ecosystem returns to its original state after a disturbance.

Restoration ecology

The study and implementation of restoring damaged ecosystems.

Watershed

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

Intermediate disturbance hypothesis

The hypothesis that ecosystems with intermediate disturbance levels are more diverse than those with high or low disturbance levels.