Energy Transfer in Ecosystems
Energy enters an ecosystem when producers capture sunlight and convert it into chemical energy during photosynthesis.
This energy becomes stored in glucose and other organic molecules that form the base of all food webs.
When herbivores consume plants, the chemical energy in biomass is transferred to them.
Carnivores then receive energy by feeding on herbivores.
At each trophic level only a fraction of the available energy is passed on because organisms use most of it for movement, growth, repair and maintaining body temperature.
As a result, energy decreases along the food chain and limits the number of trophic levels an ecosystem can support.
Energy Transformation in Ecosystems
•As energy flows through the biotic components of an ecosystem it is continually transformed.
•Producers transform light energy into chemical energy and use it to build new biomass.
•This process fixes carbon from the atmosphere and links directly to the carbon cycle.
•When consumers feed on producers, the chemical energy in plant biomass becomes part of their own tissues.
•Through respiration, both producers and consumers release carbon dioxide back into the atmosphere as some chemical energy is transformed into heat.
•Decomposers also return carbon to the environment as they break down dead biomass.
•At every stage in this cycle energy transformations result in heat loss, which means energy cannot be recycled and must be continually supplied by the Sun.