Opisthokont

Flagella and other characteristicsA common characteristic of opisthokonts is that flagellate cells, such as the sperm of most animals and the spores of chytrid fungi, propel themselves with a single posterior flagellum. It is this feature that gives this group the name Opisthokonta. In contrast, flagellate cells in other eukaryote groups propel themselves with one or more anterior flagella. Flagellate cells however have been secondarily lost in some opisthokont groups, including most of the fungi. Opisthokont characteristics include synthesis of extracellular chitin in exoskeleton, cyst/spore wall, or cell wall of filamentous growth and hyphae; the extracellular digestion of substrates with osmotrophic absorption of nutrients; and other cell biosynthetic and metabolic pathways. Early opisthokonts were likely amoeboid and phagotrophic. HistoryThe close relationship between animals and fungi was suggested by Thomas Cavalier-Smith in 1987, who used the informal name opisthokonta (the formal name has been used for the chytrids by Herbert Copeland in 1956), and was supported by later genetic studies. Early phylogenies placed fungi near the plants and other groups that have mitochondria