The seas surrounding coral reefs have the most diversity of any of the aquatic ecosystems. With such a wide abundance of life, a wide variety of complex relationships can be seen between the different animals and plants within the ecosystem. This episode of Blue Planet illustrates examples of parasitism, mutualism, commensalism, competition, and predation.
Show the video to the class. Turn on closed captioning if possible so students do not miss any of the exact species named. Have students classify each of the relationships shown.
For a more formal worksheet, see the URL below.