The variety of life in Earths waters can sometimes be overwhelming. So overwhelming that classifying by type is often seen as one's only hope of getting a handle on just what is out there. There are many different types of watery environments, and for every environment there is a group of marine creatures adapted to it, Many creatures can only live in a fresh water environment. Even more are restricted to a salt water environment. And then there are others that can safely move back and forth. Some, such as Salmon, may even be required to move back and forth at various times in their lifespan.
Types of Marine LifeEdit
- Fish - These are what we usually think of as marine life. Typically have fins and gills.
- Marine Mammals - Mammals technically evolved from reptiles that in turned evolved from aquatic life. But this sub-group having started on land has since returned to the water. Not having gills they must stay reasonably near the surface so as to be able to breath in air from the atmosphere.
- Shellfish - The common characteristic is that the various creatures live in shells.
- Coral - Sometimes mistaken for plants, they are actually groups of polyps living in complex colony structures.