Explain and define the roles of producers, primary, secondary and tertiary consumers, and decomposers

Every organism has a tropic relationship in a food chain. Producers are at the bottom of the food chain and they are autotrophs, meaning they get their nutrition through sunlight via photosynthesis, for example blackberry bushes. These are eaten by primary consumers such as rabbits, secondary consumers prey on primary consumers, an example in this case would be a fox. In some food chains there are no tertiary consumers. However food webs show the predator-prey relationship between a variety of organisms and it is possible for some organisms to have more than one role, for example a caterpillars and rabbits can both be primary consumers but a rabbit could be a secondary consumer to caterpillars. Usually ecosystems do not have enough energy to support more than 4 trophic levels (up to tertiary consumers).