APES Chapter 3

Aerobic respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Algal bloom

A rapid increase in the algal population of a waterway.

Ammonification

The process by which fungal and bacterial decomposers break down the organic nitrogen found in dead bodies and waste products and convert it into inorganic ammonium (NH4+)

Anaerobic respiration

The process by which cells convert glucose into energy in the absence of oxygen.

Assimilation

The process by which producers incorporate elements into their tissues.

Autotroph

See 'producer.'

Biogeochemical cycle

The movements of matter within and between ecosystems.

Biomass

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

Biosphere

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

Carbon cycle

The movement of carbon around the biosphere.

Carnivore

A consumer that eats other consumers.

Cellular respiration

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

Consumer

An organism that is incapable of photosynthesis and must obtain its energy by consuming other organisms. (Also known as 'heterotroph.')

Dead zone

When oxygen concentration becomes so low that it kills fish and other aquatic animals.

Decomposers

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

Denitrification

The conversion of nitrate (NO3-) in a series of steps into the gases nitrous oxide (N2O) and, eventually, nitrogen gas (N2), which is emitted into the atmosphere.

Detritivore

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

Disturbance

An event, caused by physical, chemical, or biological agents, resulting in changes in population size or community composition.

Ecological efficiency

The proportion of consumed energy that can be passed from one trophic level to another.

Evapotranspiration

The combined amount of evaporation and transpiration.

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.

Gross primary productivity (GPP)

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

Herbivore

A consumer that eats producers. (Also known as 'primary consumer.')

Heterotroph

See 'consumer.'

Hydrologic cycle

The movement of water through the biosphere.

Hypoxic

Low in oxygen.

Intermediate disturbance hypothesis

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

Leaching

The transportation of dissolved molecules through the soil via groundwater.

Limiting nutrient

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

Macronutrient

One of six key elements that organisms need in relatively large amounts: nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.

Mineralization

The process by which fungal and bacterial decomposers break down the organic matter found in dead bodies and waste products and convert it into inorganic compounds.

Net primary productivity (NPP)

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

Nitrification

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

Nitrogen cycle

The movement of nitrogen around the biosphere.

Nitrogen fixation

The process that converts nitrogen gas in the atmosphere (N2) into forms of nitrogen that producers can use.

Phosphorus cycle

The movement of phosphorus around the biosphere.

Photosynthesis

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

Primary consumer

See 'herbivore.'

Producer

An organism that uses the energy of the Sun to produce usable forms of energy. (Also known as 'autotroph.')

Resilience

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

Resistance

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

Restoration ecology

The study and implementation of restoring damaged ecosystems.

Runoff

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

Scavenger

An organism that consumes dead animals.

Secondary consumer

A carnivore that eats primary consumers.

Standing crop

The amount of biomass present in an ecosystem at a particular time.

Sulfur cycle

The movement of sulfur around the biosphere.

Tertiary consumer

A carnivore that eats secondary consumers.

Transpiration

The release of water from leaves during photosynthesis.

Trophic levels

The successive levels of organisms consuming one another.

Trophic pyramid

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

Watershed

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