In ecology, a food chain is a succession of organisms in an ecosystem that serves as continuation of food energy. An organism lower in food chain is a source of food energy (is consumed) for another organism on a higher level.

Example of a food chain:

algae --> protists --> squid --> seal --> orca

Sometimes the term food web rather than food chain is used. This is a more accurate description when looking at the more complex nature of food chains, that is most animals feed on more than one source. The relationship between organisms is underlined.

The line Phytoplankton --> Herbivorous Zooplankton --> Carnivorous Zooplankton --> Arctic Char --> Chapelin at the right hand side of the illustration below is a food chain.


Example food web