Energy Flow

In a typical trophic system energy and nutrients pass from primary producers (plants) to primary consumers (herbivores) to secondary consumers (carnivores) to tertiary consumers to quaternary consumers.

In a typical trophic system the trophic level that ultimately supports all other trophic levels is the autotrophs also known as primary producers. Most autotrophs are photosynthetic organisms that use light energy to synthesize sugars and other organic compounds, which they then use as fuel for cellular respiration and as building material for growth. Above the autotrophs are the heterotrophs, which depend on the photosynthetic output of primary consumers. Herbivores eat plants and other primary producers are primary consumers. Carnivores that eat the herbivores are secondary consumers. Carnivores that eat other carnivores are tertiary consumers. Another group of heterotrophs are the Detritivores also known as decomposers. Detritivores get their energy from detritus which is nonliving organic material such as the remains of dead organisms. Prokaryotes, fungi and other organisms that feed as detritivores form a major link between primary producers and consumers. Detritivores decompose the organic material and transfer the chemical elements in organic forms to abiotic reservoirs. Producers then recycle these elements into organic compounds. Fungi and prokaryotes are an ecosystems main decomposers which secrete enzymes and digest organic material. These decomposers than absorb the breakdown products. Tropic efficiency is the percentage of production transferred from one trophic level to the next. Trophic efficiency usually ranges from 5%-20%. Which means 80-95% of the energy available at one trophic level is not transferred to the next. Another factor that limits the number of trophic levels is the amount of solar radiation reaching the surface of the earth. This limits the photosynthetic output of the ecosystem.