Food Web, Food Chain, and Energy Pyramid

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.

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 only

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.

Gross primary productivity (GPP)

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

Trophic pyramid

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