| Phylum | # of species | Description |
| Pyrrophyta | ~2,000 | Dinoflagellates (they have two flagella). Pectin and cellulose cell walls; mostly marine; chlorophylls a and c and carotenoids; food stored as starch. |
| Euglenophyta | ~800 | Euglena and its relatives. No cell wall; mostly freshwater; 1-3 anterior flagella; chlorophylls a and b and carotenoids. |
| Chrysophyta | ~10,000 | Diatoms and their allies. Cellulose and pectin cell walls, with silica in diatoms; marine or freshwater; chlorophylls a and c and carotenoids; food stored as oils. |
| Zoomastigina | Flagellates without chloroplasts. No cell wall; freshwater, symbiotic, or parasitic; one or more flagella; e.g., Trypanosoma. | |
| Sarcodina | ~40,000 | Amoebas, foraminiferans, heliozoans, and radiolarians. No cell wall but some secrete shells with silica, calcium carbonate, etc; marine and freshwater; they have pseudopodia (extensions of membrane and cytoplasm, used for locomotion). E.g., Amoeba proteus. |
| Sporozoa | Parasitic protists. They have flagella or pseudopodia; complex life history; e.g., Toxoplasma, Plasmodium. | |
| Ciliophora | ~8,000 | Ciliates. Two types of nuclei, cilia for locomotion and food collection; no cell wall; freshwater and marine, some parasites; e.g., Paramecium, Didinium. |