Bacteria, Viruses, and ProtistsProtists |
How many species are in protist phyla, and what are some of their effects? |
Biologists estimate that millions of species of protists could exist. The following lists, to date, the protist phyla, the estimated number of species, and some examples of the protists, such as in human disease (note: as more protists—and numbers of species in the various phyla—are found each year, these numbers will no doubt change):
Phylum |
Number of Species |
Some Examples |
Rhizopoda |
Hundreds |
Amoebas (intestinal parasite Entamoeba histolytica; can cause amoebic dysentery) |
Foraminifera |
>4,000 |
Mostly oceans, for example, plankton |
Actinopoda |
Hundreds |
Radiolarians |
Chlorophyta |
7,000 |
Green algae |
Rhodophyta |
2,500–6,000 |
Red algae |
Phaeophyta |
1,500–2,000 |
Brown algae; for example, a kelp called |
Chrysophyta |
11,500 |
Diatoms |
Pyrrhophyta |
2,100 |
Dinoflagellates |
Euglenophyta |
1,000 |
Mostly single-celled aquatic algae |
Zoomastigophora (also called Zooflagellates) |
Thousands |
|
Apicomplexa |
>4,500 |
Plasmodium (malaria); Toxoplasma gondii (toxoplasmosis) |
Ciliophora |
8,000 |
Fresh or saltwater protozoa; paramecium |
Oomycota |
580 |
Water molds; downy mildew (for example, of grapes, Plasmopara viticola) |
Slime molds: |
|
|
Dictyosteliomycota (or in part, Acrasiomycota) |
>70 |
Cellular slime molds |
Myxogastria |
500 |
Plasmodial slime molds |