What are the major groups of marine life?

Question

What are the major groups of marine life? Can anyone help me? I am learning the basics before we get into depth of whatever class this is.

Answer 1

Marine animals are divided into three groups: zooplankton, nekton, and benthos.

Zooplankton are drifting animals and are usually small, however, they can grow to fairly large size.

Nekton are the free swimmers and probably the largest portion of familiar animals found in the ocean belong to this class.

Benthos are sea animals that spend their entire lives on or in the ocean bottom.

Answer 2

Two groups: good to eat and not so good to eat :)

mammal (whale, dolphin)

reptile (turtle, alligator)

cetacean

...

mollusk

shell fish

No I'm not marine biologist.  Just a seafood lover.  yummy.

Answer 3

The two largest groups of marine life are the bacteria and everything else which includes the single and multicellular eukaryotic organisms.