What are Choanoflagellates?
The choanoflagellates (meaning “collared organism with a tail”) are thought to be similar to the unicellular organism from which all animals evolved, and the closest living unicellular relative to animals. Choanoflagellates are a type of protozoa, meaning a unicellular eukaryote (complex-celled organism), in contrast to other unicellular organisms such as bacteria and archaea. Like many other microbes, choanoflagellates form colonies, which may have been the precursors of the first multicelullar organisms. Most choanoflagellates are sessile, meaning they stay in one place, fastened to the ocean floor with a stalk. The flagellum whips rapidly, driving water upwards. This flagella is surrounded by microvilli that make up the “collar” that gives the microbe its name. As the flagellum propels upwards to create a suction current, causing bits of food to get stuck to the microvilli. This strategy is called filter feeding, and it is also used by baleen whales, krill, sponges, and other marine
