Protists, Greek protiston -a meaning the (most) first of all ones, are a diverse group of organisms, comprising those eukaryotes that can't be classified in any of the other eukaryotic kingdoms as fungi, animals, or plants. They are usually treated as the kingdom Protista or Protoctista. Protoctists (or protists) are a paraphyletic grade, rather than a natural, (monophyletic) group, and so don't have much in common besides a relatively simple organization -- either they're unicellular, or they'… (More on Protista)