Freshwater - the least common ecosystem. These system comprise lakes, rivers, streams, and springs; supports a variety of animals, plants, fungi, protists and prokaryotes.
Marine - most common ecosystem. Consist three basic type: shallow ocean, deep ocean water, and deep ocean bottom.
Terrestrial - The land, the surface of the earth, the ground, the surface of the sea, and the land beneath the sea, is also grouped called biomes
