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Euglenidae
Euglenaceae (also known as Euglenidae) is a family of flagellates in the phylum Euglenozoa. The family includes the most well-known euglenoid genus, ''Euglena''. Nomenclature The family Euglenaceae is also known by the name Euglenidae. The origin of this dual naming system is because of the history of protists. Euglenids have been treated as both algae and protozoans, which are governed by separate nomenclature codes. If treated as an alga, it would fall under the International Code of Nomenclature for algae, fungi, and plants (ICN) and its correct name would be Euglenaceae; if treated under the International Code of Zoological Nomenclature (ICZN) it is called Euglenidae. Euglenids such as these are considered to be ambiregnal protists due to their parallel naming systems. Morphology Euglenaceae show the most morphological diversity within the class Euglenophyceae. They are mostly single-celled organisms, except for the genus ''Colacium''. They are free-living or sometimes in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglenozoa
Euglenozoa are a large group of flagellate Discoba. They include a variety of common free-living species, as well as a few important parasites, some of which infect humans. Euglenozoa are represented by four major groups, ''i.e.,'' Kinetoplastea, Diplonemea, Euglenida, and Symbiontida. Euglenozoa are unicellular, mostly around in size, although some euglenids get up to long. Structure Most euglenozoa have two flagella, which are inserted parallel to one another in an apical or subapical pocket. In some these are associated with a cytostome or mouth, used to ingest bacteria or other small organisms. This is supported by one of three sets of microtubules that arise from the flagellar bases; the other two support the dorsal and ventral surfaces of the cell. Some other euglenozoa feed through absorption, and many euglenids possess chloroplasts, the only eukaryotes outside Diaphoretickes to do so without performing kleptoplasty, and so obtain energy through photosynthesis. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglenophyceae
Euglenophyceae (ICNafp, proposed as a class) or Euglenea (ICZN, proposed as a class) is an unranked clade of single-celled algae belonging to the phylum Euglenozoa. They have chloroplasts originated from an event of secondary endosymbiosis with a green alga. They are distinguished from other algae by the presence of paramylon as a storage product and three membranes surrounding each chloroplast. Description Euglenophyceae are unicellular algae, protists that contain chloroplasts. Their chloroplasts originated from a secondary endosymbiosis with a green alga, particularly from the order Pyramimonadales, and contain chlorophylls ''a'' and ''b''.Some have secondarily lost this ability and evolved toward osmotrophy. In addition to photosynthetic plastids, most species have a photosensitive eyespot. Ecology Euglenophyceae are mainly present in the water column of freshwater habitats. They are abundant in small eutrophic water bodies of temperate climates, where they ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Félix Dujardin
Félix Dujardin (5 April 1801 – 8 April 1860) was a French biologist born in Tours. He is remembered for his research on protozoans and other invertebrates. Biography In 1840 Dujardin was appointed professor of geology and mineralogy at the University of Toulouse, and during the following year was a professor of zoology and botany at Rennes. In regard to his educational background, Dujardin was largely self-taught, the son of a watchmaker. Dujardin worked with microscopic animal life, and in 1834 proposed that a new group of one-celled organisms be called Rhizopoda. He denied naturalist Christian Gottfried Ehrenberg's theory that microscopic organisms were "complete organisms" similar to higher animals, specifically noting that they had specialized structures unique to single-celled organisms, which meant that the foraminiferan he was studying was not, as his contemporaries believed it to be, a mollusc. In addition to his studies of microscopic life, he did extensive rese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglena Archaeoplastidiata
''Euglena'' is a genus of single-celled, flagellate eukaryotes. It is the best-known and most widely studied member of the class Euglenoidea, a diverse group containing some 54 genera and at least 200 species. Species of ''Euglena'' are found in fresh water and salt water. They are often abundant in quiet inland waters where they may bloom in numbers sufficient to color the surface of ponds and ditches green ('' E. viridis'') or red ('' E. sanguinea''). The species ''Euglena gracilis'' has been used extensively in the laboratory as a model organism. Most species of ''Euglena'' have photosynthesizing chloroplasts within the body of the cell, which enable them to feed by autotrophy, like plants. However, they can also take nourishment heterotrophically, like animals. Since ''Euglena'' have features of both animals and plants, early taxonomists, working within the Linnaean two-kingdom system of biological classification, found them difficult to classify. It was the quest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euglenales
Euglenales (also known as Euglenida) is an order of flagellates in the phylum Euglenozoa. The family includes the most well-known euglenoid genus, '' Euglena'', as well as other common genera like '' Phacus'' and '' Lepocinclis''. Nomenclature The order Euglenales is also known by the name Euglenida. The origin of this dual naming system is because of the history of protists. Euglenids have been treated as both algae and protozoans, which are governed by separate nomenclature codes. If classified as an alga, it would fall under the International Code of Botanical Nomenclature (ICBN) and its correct name would be Euglenales; if classified as a protozoan, it would fall under the International Code of Zoological Nomenclature (ICZN) and would be called Euglenida. Euglenids such as these are considered to be ambiregnal protists due to their parallel naming systems. Description Euglenales consists mostly of freshwater organisms, in contrast to its sister Eutreptiales which is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discoplastis
''Discoplastis'' is a genus of euglenoid algae belonging to the family Phacaceae. The species of this genus are found in Europe, Northern America, Southeastern Asia and Australia. ''Discoplastis'' consists of solitary, free-living cells with one emergent flagellum. The cells have a flexible, spirally striated pellicle and are therefore capable of metaboly. When swimming, the cells are a variety of different but characteristic shapes (cylindrical, fusiform, hourglass-shaped, etc.). The posterior of the cell ends in a pointed, colorless cell. Within each cell there are numerous small, discoid chloroplast lacking pyrenoids. Cells have paramylon grains; the paramylon grains may be monomorphic (all small) or dimorphic (some large, some small). As with other euglenoids, the cell has a reddish eyespot (stigma). ''Discoplastis'' can be distinguished by to the combination of small, discoid parietal chloroplasts without pyrenoids (a synapomorphy for the family Phacaceae), and its fle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phacus
''Phacus'' is a genus of unicellular euglenoids, of the phylum Euglenozoa (also known as Euglenophyta), characterized by its flat, leaf-shaped structure, and rigid cytoskeleton known as a pellicle. These eukaryotes are mostly green in colour, and have a single flagellum that extends the length of their body. They are morphologically very flat, rigid, leaf-shaped, and contain many small discoid chloroplasts. ''Phacus'' are commonly found in freshwater habitats around the globe and include several hundred species that continue to be discovered to this day. There are 564 species of ''Phacus'' in the database, but only 171 have been accepted taxonomically. It is a large and complex genus, with ongoing species revisions continuing to the present. Etymology The genus name is believed to have originated from the Greek word φακός (''phakós''), meaning lentil or lens. This may be due to the general round or oval shape of the many species that are part of this genus. Its origins d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepocinclis
''Lepocinclis'' is a genus of algae belonging to the family Phacaceae. The genus has a cosmopolitan distribution, and is primarily part of the plankton in freshwater habitats (rarely brackish ones). Description ''Lepocinclis'' consists of single, free-swimming cells, with the flagella, eyespot (stigma), and flagellar swelling similar to that of ''Euglena''. The cells are rigid or semi-rigid (they may bend somewhat, but are not metabolic). The cell shape is variable but species-specific: they may be ovoid, fusiform, cylindrical, sometimes twisted; the cell is usually not flattened (rarely flattened or triangular) in cross section. Cells often with a tapering posterior spine; the cell is surrounded by a pellicle with spiral striations. Cells are typically filled with numerous small, discoid chloroplasts without pyrenoids, which give the cell a green color. A few species have secondarily lost their chloroplasts, and are therefore colorless. Cells are also filled with paramylon gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyletic
In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent common ancestor (or more precisely an ancestral population), i.e. excludes non-descendants of that common ancestor # the grouping contains all the descendants of that common ancestor, without exception Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic'' grouping meets 1. but not 2., thus consisting of the descendants of a common ancestor, excepting one or more monophyletic subgroups. A '' polyphyletic'' grouping meets neither criterion, and instead serves to characterize convergent relationships of biological features rather than genetic relationships – for example, night-active primates, fruit trees, or aquatic insects. As such, these characteristic features of a polyphyletic grouping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumscription (taxonomy)
In biological taxonomy, circumscription is the content of a taxon, that is, the delimitation of which subordinate taxa are parts of that taxon. For example, if we determine that species X, Y, and Z belong in genus A, and species T, U, V, and W belong in genus B, those are our circumscriptions of those two genera. Another systematist might determine that T, U, V, W, X, Y, and Z all belong in genus A. Agreement on circumscriptions is not governed by the Codes of Zoological or Botanical Nomenclature, and must be reached by scientific consensus. A goal of biological taxonomy is to achieve a stable circumscription for every taxon. This goal conflicts, at times, with the goal of achieving a natural classification that reflects the evolutionary history of divergence of groups of organisms. Balancing these two goals is a work in progress, and the circumscriptions of many taxa that had been regarded as stable for decades are in upheaval in the light of rapid developments in molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrenoid
Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''Annu. Rev. Plant Biol.'', 56, 99-131. and in a single group of land plants, the hornworts.Villarreal, J. C., & Renner, S. S. (2012) Hornwort pyrenoids, carbon-concentrating structures, evolved and were lost at least five times during the last 100 million years. ''Proceedings of the National Academy of Sciences'',109(46), 1873-1887. Pyrenoids are associated with the operation of a carbon-concentrating mechanism (CCM). Their main function is to act as centres of carbon dioxide (CO2) fixation, by generating and maintaining a CO2-rich environment around the photosynthesis, photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Pyrenoids therefore seem to have a role analogous to that of carboxysomes in cyanobacteria. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
