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The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a large group of flagellate protists that constitute the phylum Dinoflagellata. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on temperature, salinity, or depth. Many dinoflagellates are known to be photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey (phagotrophy). In terms of number of species, dinoflagellates form one of the largest groups of marine eukaryotes, although this group is substantially smaller than the diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are colorless predators on other protozoa, and a few forms are parasitic (see for example ''Oodinium'', ''Pfiesteria''). Some dinoflagellates produce resting stages, called dinoflagellate cysts or dinocysts, as part of their life cycles. Dinoflagellates are considered to be protists, with their own division, Dinoflagellata. About 1,555 species of free-living marine dinoflagellates are currently described. Another estimate suggests ca. 2,000 living species, of which more than 1,700 are marine (free-living as well as benthic) and about 220 are from freshwater. The latest estimates suggest a total of 2,294 living dinoflagellate species, which includes marine, freshwater and parasitic dinoflagellates. An algal bloom of dinoflagellates can result in a visible coloration of the water colloquially known as red tide. ==History== In 1753, the first modern dinoflagellates were described by Henry Baker as "Animalcules which cause the Sparkling Light in Sea Water",〔Baker, M., 1753. Employment for the microscope. Dodsley, London, 403 pp.〕 and named by Otto Friedrich Müller in 1773.〔Müller, O.F. 1773. Vermium terrestrium et fluviatilium, seu Animalium Infusoriorum, Helmithicorum et Testaceorum, non marinorum, succincta historia, vol. 1. Pars prima. p. 34, 135. Faber, Havniae, et Lipsiae 1773.〕 The term derives from the Greek word δῖνος (''dinos''), meaning 'whirling', and Latin ''flagellum'', a diminutive term for a whip or scourge. In the 1830s, the German microscopist Christian Gottfried Ehrenberg examined many water and plankton samples and proposed several dinoflagellate genera that are still used today including ''Peridinium, Prorocentrum'' and ''Dinophysis''.〔Ehrenberg C.G. (1832) Beiträge zur Kenntnis der Organisation der Infusorien und ihrer geographischer Verbreitung, besonders in Sibirien. — Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin. Aus dem Jahre 1830. Physikalische Abhandlungen 1830: 1-88, Pls 1-8.〕 These same dinoflagellates were first defined by Otto Bütschli in 1885 as the flagellate order Dinoflagellida.〔Bütschli O. (1885) 3. Unterabtheilung (Ordnung) Dinoflagellata. – In: Dr. H.G. Bronn's Klassen und Ordnungen des Thier-Reichs, wissenschaftlich dargestellt in Wort und Bild. Erster Band Protozoa. – C.F. Winter'sche Verlagshandlung, Leipzig und Heidelberg. Pp. 906-1029; Pl.〕 Botanists treated them as a division of algae, named Pyrrophyta or Pyrrhophyta ("fire algae"; Greek ''pyrr(h)os'', fire) after the bioluminescent forms, or Dinophyta. At various times, the cryptomonads, ebriids, and ellobiopsids have been included here, but only the last are now considered close relatives. Dinoflagellates have a known ability to transform from noncyst to cyst-forming strategies, which makes recreating their evolutionary history extremely difficult. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「dinoflagellate」の詳細全文を読む スポンサード リンク
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