Microbial Eukaryotes.
Microbial eukaryotes (Protist) are members of the four following major groups:
The "true nucleus" of eukaryotes is only one of their distinguising features. Taxonomic groupings of eukaryotes frequently are based on shared morphologic properties, and it is noteworthy that many taxonomically useful determinants are those associated with reproduction. Almost all of these succesful species are those in which closely related cells, members of the same species, can recombine to form viable offspring. Structures that contribute directly or indirectly to the reproductive event tend to be highly developed and, with minor modifications among closely related species, extensively consserved. It should be noted that these groupings are not necessarily phylogenetic, closely related organisms may have been categorized separately because underlying biochemical and genetic similarities may not have been recognized.