A3.4.5 Food Chains & Food Webs


‘Food Chain’ is a commonly used term. It is a simplistic representation of the eating relationships between different species in an ecosystem. It will show the food energy being transferred from one organism to the next. At the bottom it will start with an organism that is able to manufacture its own food and at the top will often be the highest predator in that chain. However, some food chains continue after the highest predator with the species that is responsible for that predator’s decay upon death (e.g. bacteria and fungi), known as decomposers. Each level in a food chain is known as a ‘trophic level’.

They are simplistic because a food chain will usually only show one pathway of energy and material transfer, i.e. one predator eats an animal, which in turn feeds on another animal. However in reality, most consumers can feed on multiple species and, in turn, can be fed upon by multiple other species. An example is provided below:

Source: University of Maine Cooperative Extension, http://www.umaine.edu/umext/earthconnections/earth/chapter3.htm