Protista

The Kingdom Protista (one of the five kingdoms in Linnaean Taxonomy) includes all the Eukaryotes except for the Plantae, Fungi, and Animalia. A few forms are multicellular, ie the Phaeophyta (brown algae) and Rhodophyta (red algae). The vast majority, though, are single-celled and are typically only 0.01-0.5 mm in size, too small to be seen without a microscope. Protists are ubiquitous throughout aqueous environments and the soil, commonly surviving dry periods in the form of cysts; a few are important parasites.

Traditionally protists have been divided into:

Plant-like forms that have chloroplasts, the Algae;
Fungus-like forms, the Slime molds and Oomycota;
Animal-lie forms, the Protozoa, generally divided on the basis of morphology and locomotion into:

Except for the ciliates and Oomycota, these are all polyphyletic and frequently overlapping. More recently protists have been divided into more genuine groups on the basis of ultrastructural and chemical features. Aside from basal forms, these can be assorted into a few broad categories on the basis of the the form of the mitochondria and in particular the cristae within them.

One of the standard, and heavily inadequate, break-ups into phyla:

Phylum Caryoblastea=Pelobionta (Pelobionts)

Phylum Dinoflagellata

Phylum Rhizopoda (polyphyletic - see Amoeboid, especially Ramicristates)

Phylum Chrysophyta (basal Stramenopiles

Phylum Haptophyta=Prymnesiophyta (Haptophytes)

Phylum Euglenophyta (Euglenids)

Phylum Cryptophyta (Cryptomonads)

Phylum Zoomastigina (polyphyletic - see Flagellate for now)

Phylum Xanthophyta

Phylum Eustigmatophyta

Phylum Bacillariophyta (Diatoms)

Phylum Phaeophyta (brown algae)

Phylum Rhodophyta (red algae)

Phylum Chlorophyta (basal Plantae)

Phylum Actinopoda (polyphyletic - see Amoeboid for now)

Phylum Granuloreticulosa

Phylum Ciliophora

Phylum Apicomplexa

Phylum Myxozoa=Cnidosporidia

Phylum Labyrinthulomycota=Labyrinthulida (Labyrinthulida)

Phylum Acrasiomycota (polyphyletic)

Phylum Myxomycota

Phylum Plasmodiophoromycota=Plasmodiophorida

Phylum Hyphochytridiomycota

Phylum Oomycota