Trophic Levels

• Trophic level of an organism refers to its position in the food chain, food web or pyramid of biomass.
• Transfer of biomass occurs through the food chain, food web or pyramid of biomass.
• Pyramids of biomass show the total mass of organisms in each trophic level of a food chain.
• Level one in a food chain is occupied by producers, photosynthetic organisms which use energy from light to produce biomass, about 1% of light is used.
• Level two in a food chain is occupied by primary consumers, herbivores that eat plants or algae.
• Level three in a food chain is occupied by secondary consumers, carnivores that eat herbivores.
• Level four in a food chain is occupied by tertiary consumers, carnivores that eat secondary consumers.
• The final trophic level in a food chain is made from apex predators which are carnivores with no predators, such as humans.
• Decomposers break down dead organisms using extracellular digestion.
• Biomass is lost between trophic levels due to not all plant or animal material being digested, biomass lost through excretion or decay, and biomass used in other processes such as movement and keeping warm.
• About 10% of biomass is transferred to the next level.
• Biomass is created by producers and is passed along the food chain through feeding.