They live in the sea, on land, and in fresh water.
Many species are of economic interest or important as indicators of environmental quality.
Furthermore, consequentially to their long and well documented paleontological history they play an important role in stratigraphy and evolutionary research. The molluscs comprise chitons, gastropods, bivalves, octopuses and squids, tusk shells and the two less well known groups Monoplacophora and Aplacophora. Some further information can be found at the sites below.