Fragilaria Gracilis

	Fragilaria Gracilis ''Fragilaria gracilis'' is a species of freshwater pennate diatoms. ''F. gracilis'' is reported from many parts of Europe, in Sweden even as one of the dominant freshwater diatom taxa. Identification Despite its frequent occurrence, there has been some confusion about the identification of this taxon. However, a recent study using both molecular and morphological data has shown that ''F. gracilis'' is separated from other similar long ''Fragilaria'' taxa, and can be identified by both its rbcL barcode, and by using light microscopy (LM). In LM, is can be identified by its quite stable character of almost parallel valve sides (in the long cells) and the clear opposite arrangement of the striae giving the impression of regularly arranged parallel lines across the valve in LM. These characters are also in agreement with Østrup's original description of 1910 of almost linear valves, and Tuji's Tuji, A. (2007) Type examination of ''Fragilaria gracilis'' Østrup (Bacillariophyceae). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	SAR Supergroup The SAR supergroup, also just SAR or Harosa, is a clade that includes stramenopiles (heterokonts), alveolates, and Rhizaria. The name is an acronym derived from the first letters of each of these clades; it has been alternatively spelled "RAS". The term "Harosa" (at the subkingdom level) has also been used. The SAR supergroup is a node-based taxon. Note that as a formal taxon, "Sar" has only its first letter capitalized, while the earlier abbreviation, SAR, retains all uppercase letters. Both names refer to the same group of organisms, unless further taxonomic revisions deem otherwise. Members of the SAR supergroup were once included under the separate supergroups Chromalveolata ( Chromista and Alveolata) and Rhizaria, until phylogenetic studies confirmed that stramenopiles and alveolates diverged with Rhizaria. This apparently excluded haptophytes and cryptomonads, leading Okamoto ''et al.'' (2009) to propose the clade Hacrobia to accommodate them. Phylogeny Based on a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Heterokont Heterokonts are a group of protists (formally referred to as Heterokonta, Heterokontae or Heterokontophyta). The group is a major line of eukaryotes. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which are a primary component of plankton. Other notable members of the Stramenopiles include the (generally) parasitic oomycetes, including ''Phytophthora'', which caused the Great Famine of Ireland, and ''Pythium'', which causes seed rot and damping off. The name "heterokont" refers to the type of motile life cycle stage, in which the flagellated cells possess two differently arranged flagella (see zoospore). History In 1899, Alexander Luther created the term "Heterokontae" for some algae with unequal flagella, today called Xanthophyceae. Later, some authors (e.g., Copeland, 1956) included other groups in Heterokonta, expanding the name's sense. The term continues to be applied in different ways, leading to Heterokontophyta being applied al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Bacillariophyceae Bacillariophyceae is a group of pennate diatoms with a raphe (raphids). According to Ruggiero et al., 2015, the diatoms are treated as follows. This treatment largely reflects that used by Algaebase as at 2015, and is also reflected in the current (mid 2020) treatment used iDiatomBase the World Register of Marine Species (WoRMS) of which DiatomBase is a part, and the Catalogue of Life. This treatment is identical to that of Round et al., 1990, except that all diatoms are treated as a single class, Round et al.'s classes are reduced to subclasses, and the latter's original subclasses are omitted. It has 3 subclasses, '' Bacillariophycidae'', '' Coscinodiscophycidae'' and '' Fragilariophycidae'' Subclass Bacillariophycidae Contains the following orders; * Achnanthales (2k) * Bacillariales (3k) * Cymbellales (4k) * Dictyoneidales (17) * Eunotiales (2k) * Lyrellales (38) * Mastogloiales (825) * Naviculales (18k) * Rhopalodiales (527) * Surirellales (2k) * Thalassiophysales ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Fragilariales Fragilariophyceae is a group of pennate diatoms lacking a raphe. Examples It includes the following genera: Fragilariales '' Ardissonea'' ''Asterionella'' ''Asterionellopsis'' '' Catacombas'' '' Diatoma'' ''Fragilaria'' '' Fragilariforma'' '' Grammonema'' '' Hyalosynedra'' '' Neofragilaria'' '' Opephora'' '' Pseudostaurosira'' '' Punctastriata'' '' Staurosira'' '' Staurosirella'' '' Synedra'' '' Synedropsis'' '' Tabularia'' '' Ulnaria'' Striatellales '' Hyalosira'' '' Striatella'' '' Toxarium'' Other ''Climacosphenia'' '' Cyclophora'' '' Delphineis'' '' Protoraphis'' '' Rhabdonema'' '' Rhaphoneis'' ''Tabellaria ''Tabellaria'' is a genus of freshwater diatoms (Bacillariophyta). They are cuboid in shape, and the frustules (siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in natu ...'' '' Thalassionema'' References Heterokont classes {{Diatom-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Fragilaria ''Fragilaria'' is a genus of freshwater and saltwater diatoms. It is usually a colonial diatom, forming filaments of cells mechanically joined by protrusions on the face and in the center of their valves. The individual diatoms appear swollen in their centers where they are joined to the colonial ribbon. the genus grows as both plankton and benthic species, free living in colonies or epiphytic. Some species are bloom forming diatoms in eutrophic lakes. The type species is '' Fragilaria pectinalis'' Lyngbye from designating a lectotype from ''Conferva pectinalis'' O.F.Müller. The taxonomy of the genus is still uncertain. ''Fragilaria'' has been the dominant genus of diatoms in Lake Mývatn A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ... in Iceland for at least 1200 years. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Diatom A diatom (New Latin, Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of the Earth's Biomass (ecology), biomass: they generate about 20 to 50 percent of the oxygen produced on the planet each year, take in over 6.7 billion metric tons of silicon each year from the waters in which they live, and constitute nearly half of the organic material found in the oceans. The Protist shell, shells of dead diatoms can reach as much as a half-mile (800 m) deep on the ocean floor, and the entire Amazon basin is fertilized annually by 27 million tons of diatom shell dust transported by transatlantic winds from the African Sahara, much of it from the Bodélé Dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Model Organisms A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Model organisms are widely used to research human disease when human experimentation would be unfeasible or unethical. This strategy is made possible by the common descent of all living organisms, and the conservation of metabolic and developmental pathways and genetic material over the course of evolution. Studying model organisms can be informative, but care must be taken when generalizing from one organism to another. In researching human disease, model organisms allow for better understanding the disease process without the added risk of harming an actual human. The species chosen will usually meet a determined taxonomic equivalency to humans, so as to react to disease or its treatment in a way that resembles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Fragilariophyceae Fragilariophyceae is a group of pennate diatoms lacking a raphe. Examples It includes the following genera: Fragilariales '' Ardissonea'' ''Asterionella'' ''Asterionellopsis'' '' Catacombas'' '' Diatoma'' ''Fragilaria'' '' Fragilariforma'' '' Grammonema'' '' Hyalosynedra'' '' Neofragilaria'' '' Opephora'' '' Pseudostaurosira'' '' Punctastriata'' '' Staurosira'' '' Staurosirella'' '' Synedra'' '' Synedropsis'' '' Tabularia'' '' Ulnaria'' Striatellales '' Hyalosira'' '' Striatella'' '' Toxarium'' Other ''Climacosphenia'' '' Cyclophora'' '' Delphineis'' '' Protoraphis'' '' Rhabdonema'' '' Rhaphoneis'' '' Tabellaria'' ''Thalassionema ''Thalassionema'' is a genus of Chromista belonging to the family Thalassionemataceae. The genus was described in 1902 by Albert Grunow, Grunow ex Mereschkowsky. Species: * ''Thalassionema nitzschioides'' Grunow, 1862 References Fragi ...'' References Heterokont classes {{Diatom-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]