C4.2 Energy flow

Autotroph (or producer)

an organism that is able to form organic substances from simple inorganic substances such as carbon dioxide.

Biomass

the total dry mass of living matter/ unit area

Cell respiration

the controlled release of energy from organic compounds to produce ATP; results in heat loss to the environment in every trophic level

Chemical energy

form of energy in organic molecules

Ecosystem

a system that includes all biotic factors (living organisms) in an area as well as its abiotic factors (physical environment) functioning together as a unit.

Energy flow

ONE way movement of energy through an ecosystem's trophic levels.

primary consumer

eats plants / producers (herbivore)

food chain

A model for energy flow in an ecosystem where organisms transfer energy through feeding relationships

Heterotroph

an organism that obtains organic molecules from other organisms, living or dead.

Light energy

the energy produced by the sun that can be captured by photoautotrophs.

Photosynthesis

process in which producers capture light energy and convert it to chemical energy in organic molecules.

Producer (or autotroph)

an organism that is able to form organic substances from simple inorganic substances such as carbon dioxide and water.

Pyramids of energy

a graphical model to show how the energy flows through a food chain

Secondary consumer

an organism that feeds on primary consumers.

Trophic level

the position in a food chain occupied by an organism / population.

primary productivity

the rate at which energy is converted by photosynthetic and chemosynthetic autotrophs into chemical energy in organic molecules (kJ or kg/area/time)

secondary productivity

rate of increase in biomass by organisms that eat plants (herbivores) kJ or kg/area/time

Energy losses in food chains

uneaten material, undigested material & cell respiration

Calorimetry

The precise measurement of heat flow from combustion of organic matter to determine its energy content

Egestion

removal of undigested waste by consumers (faeces)

Assimilation

storage or use of organic molecules in cells of organisms

Excretion

Process by which metabolic wastes (produced in cells) are eliminated from the body

Digestion

process of hydrolysis of macromolecules carried out by heterotrophs for absorption of monomers

ingestive heterotrophs

consume / eat / ingest food and digest it inside their bodies (internally)

Saprotrophs

heterotrophs that obtain organic nutrients from detritus by external digestion.