Energy and Matter Flow in Ecosystems Many of the most important relationships between living organisms and the environment are controlled ultimately by the amount of available incoming energy received at the Earth's surface from the sun. It is this energy which helps to drive biotic systems. The sun's energy allows plants to convert inorganic chemicals into organic compounds. Only a very small proportion of the sunlight received at the Earth's surface is transformed into biochemical form. Several studies have been carried out to determine this amount.
Radiant energy exists in the form of electromagnetic energy , such as light.
Fixed energy is the potential chemical energy found in organic substances. This energy can be released through respiration . Organisms that can take energy from inorganic sources and fix it into energy rich organic molecules are called autotrophs . If this energy comes from light then these organisms are called photosynthetic autotrophs . In most ecosystems plants are the dominant photosynthetic autotroph.