Choanoflagellates: biology, classification, and evolutionary significance

¶ … life forms in the world. It is important to examine the biology of chonanoflagellates and how it occurs in nature.

Choanoflagellates

Choanoflagellates are colorless flagellates which are 5-10 micron and have a well-defined collar. They may be individual or live in colonies and "may live free in the water, or attached to substrates such as the spines of the Chaetoceros affinis (thalassa.gso.uri.edu/rines/ecology/choanofl.htm)."

Choanoflagellates are made up of only about 150 species and are not "a diverse group of protists. They are small single-celled protests, found in both fresh waters and the oceans, taking their name ("collar-flagellate") from the circle of closely packed microvilli, or slender fingerlike projections, that surrounds the single flagellum by which choanoflagellates both move and take in food (www.ucmp.berkeley.edu/protista/choanos.html)." The funnel-shaped collar is contractible and strains out the bacteria which the choanoflagellate feeds on (www.mhhe.com/biosci/genbio/biolink/student/olc2/chap31outline.htm).