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Vitreochlamys Pinguis
''Vitreochlamys'' is a genus of green algae in the family Chlamydomonadaceae.See the NCBIbr>webpage on Vitreochlamys Data extracted from the It is sometimes known by the name ''Sphaerellopsis'', published by Aleksandr Arkadievich Korshikov. However, that name is an illegitimate later homonym, preceded by ''Sphaerellopsis'' . It is commonly found in freshwater habitats. ''Vitreochlamys'' is a unicellular, free-living organism. Cells are spherical, ovoidal, or ellipsoidal, with two equal flagella at one end, and two or three contractile vacuoles at the base of the flagella. The cell wall is swollen, giving the appearance of a layer surrounding the protoplast. Cells contain a single large chloroplast filling the cell, with pyrenoids and a stigma. Asexual reproduction occurs by the formation of zoospores within the parent cell wall; sexual reproduction has not been observed. Species are distinguished from each other by their cell shape, number of contractile vacuoles and py ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreochlamys Aulata
''Vitreochlamys'' is a genus of green algae in the family Chlamydomonadaceae.See the NCBIbr>webpage on Vitreochlamys Data extracted from the It is sometimes known by the name ''Sphaerellopsis'', published by Aleksandr Arkadievich Korshikov. However, that name is an illegitimate later homonym, preceded by ''Sphaerellopsis'' . It is commonly found in freshwater habitats. ''Vitreochlamys'' is a unicellular, free-living organism. Cells are spherical, ovoidal, or ellipsoidal, with two equal flagella at one end, and two or three contractile vacuoles at the base of the flagella. The cell wall is swollen, giving the appearance of a layer surrounding the protoplast. Cells contain a single large chloroplast filling the cell, with pyrenoids and a stigma. Asexual reproduction occurs by the formation of zoospores within the parent cell wall; sexual reproduction has not been observed. Species are distinguished from each other by their cell shape, number of contractile vacuoles and py ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomen Illegitimum
''Nomen illegitimum'' (Latin for illegitimate name) is a technical term, used mainly in botany. It is usually abbreviated as ''nom. illeg.'' Although the International Code of Nomenclature for algae, fungi, and plants uses Latin terms for other kinds of name (e.g. ''nomen conservandum'' for " conserved name"), the glossary defines the English phrase "illegitimate name" rather than the Latin equivalent.''Melbourne Code''Glossary/ref> However, the Latin abbreviation is widely used by botanists and mycologists. A superfluous name is often an illegitimate name. Again, although the glossary defines the English phrase, the Latin equivalent ''nomen superfluum'', abbreviated ''nom. superfl.'' is widely used by botanists. Definition A ''nomen illegitimum'' is a validly published name, but one that contravenes some of the articles laid down by the International Botanical Congress. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyphyletic
A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of convergent evolution. The arrangement of the members of a polyphyletic group is called a polyphyly .. ource for pronunciation./ref> It is contrasted with monophyly and paraphyly. For example, the biological characteristic of warm-bloodedness evolved separately in the ancestors of mammals and the ancestors of birds; "warm-blooded animals" is therefore a polyphyletic grouping. Other examples of polyphyletic groups are algae, C4 photosynthetic plants, and edentates. Many taxonomists aim to avoid homoplasies in grouping taxa together, with a goal to identify and eliminate groups that are found to be polyphyletic. This is often the stimulus for major revisions of the classification schemes. Researchers concerned more with ecology than with systema ... [...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. 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 molecular phylogenetics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volvocaceae
The Volvocaceae are a family of unicellular or colonial biflagellates, including the typical genus ''Volvox''. The family was named by Ehrenberg in 1834,From p. 281: ''"VOLVOCINA Nova Familia."'' (Volvocina New Family.) ote: According to p. 145, Ehrenberg's paper was first presented in 1832, revised somewhat, and published in 1834./ref> and is known in older classifications as the Volvocidae. All species are colonial and inhabit freshwater environments. Description The simplest of the Volvocaeans are ordered assemblies of cells, each similar to the related unicellular protist ''Chlamydomonas'' and embedded in a gelatinous matrix. In the genus ''Gonium'', for example, each individual organism is a flat plate consisting of 4 to 16 separate cells, each with two flagella. Similarly, the genera ''Eudorina'' and ''Pandorina'' form hollow spheres, the former consisting of 16 cells, the latter of 32 to 64 cells. In these genera each cell can reproduce a new organism by mitosis.Scot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Diversity Flagella types Zoospores may possess one or more distinct types of flagella - tinsel or "decorated", and whiplash, in various combinations. *Tinsellated (straminipilous) flagella have lateral filaments known as mastigonemes perpendicular to their main axis, which allow for more surface area, and disturbance of the medium, giving them the property of a rudder, that is, used for steering. *Whiplash flagella are straight, to power the zoospore through its medium. Also, the "default" zoospore only has the propelling, whiplash flagella. Both tinsel and whiplash flagella beat in a sinusoidal wave pattern, but when both are present, the tinsel beats in the opposite direction of the whiplash, to give two axes of control of motility. Morphological types In eukaryotes, the four main types ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyespot Apparatus
The eyespot apparatus (or '' stigma'') is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids. It allows the cells to sense light direction and intensity and respond to it, prompting the organism to either swim towards the light (positive phototaxis), or away from it (negative phototaxis). A related response ("photoshock" or photophobic response) occurs when cells are briefly exposed to high light intensity, causing the cell to stop, briefly swim backwards, then change swimming direction. Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis. Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red red pigment granules. Signals relayed from the eyespot photoreceptors result in alteration of the beating pattern of the flagella, generating a pho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrenoid
Pyrenoids are sub-cellular 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 photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Pyrenoids therefore seem to have a role analogous to that of carboxysomes in cyanobacteria. Algae are restricted to aqueous env ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in the cells. The ATP and NADPH is then used to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. A chloroplast is characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis. Chloroplasts are highly dynamic—they circulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contractile Vacuole
A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae. It was previously known as pulsatile or pulsating vacuole. Overview The contractile vacuole is a specialized type of vacuole that regulates the quantity of water inside a cell. In freshwater environments, the concentration of solutes is hypotonic, lesser outside than inside the cell. Under these conditions, osmosis causes water to accumulate in the cell from the external environment. The contractile vacuole acts as part of a protective mechanism that prevents the cell from absorbing too much water and possibly lysing (rupturing) through excessive internal pressure. The contractile vacuole, as its name suggests, expels water out of the cell by contracting. The growth (water gathering) and contraction (water expulsion) of the contractile vacuole are periodical. One cycle takes several seconds, depending on the species and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aleksandr Arkadievich Korshikov
Alexander is a male given name. The most prominent bearer of the name is Alexander the Great, the king of the Ancient Greek kingdom of Macedonia who created one of the largest empires in ancient history. Variants listed here are Aleksandar, Aleksander and Aleksandr. Related names and diminutives include Iskandar, Alec, Alek, Alex, Alexandre, Aleks, Aleksa and Sander; feminine forms include Alexandra, Alexandria, and Sasha. Etymology The name ''Alexander'' originates from the (; 'defending men' or 'protector of men'). It is a compound of the verb (; 'to ward off, avert, defend') and the noun (, genitive: , ; meaning 'man'). It is an example of the widespread motif of Greek names expressing "battle-prowess", in this case the ability to withstand or push back an enemy battle line. The earliest attested form of the name, is the Mycenaean Greek feminine anthroponym , , (/Alexandra/), written in the Linear B syllabic script. Alaksandu, alternatively called ''Alakasandu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitreochlamys Fluviatilis
''Vitreochlamys'' is a genus of green algae in the family Chlamydomonadaceae.See the NCBIbr>webpage on Vitreochlamys Data extracted from the It is sometimes known by the name ''Sphaerellopsis'', published by Aleksandr Arkadievich Korshikov. However, that name is an illegitimate later homonym, preceded by ''Sphaerellopsis'' . It is commonly found in freshwater habitats. ''Vitreochlamys'' is a unicellular, free-living organism. Cells are spherical, ovoidal, or ellipsoidal, with two equal flagella at one end, and two or three contractile vacuoles at the base of the flagella. The cell wall is swollen, giving the appearance of a layer surrounding the protoplast. Cells contain a single large chloroplast filling the cell, with pyrenoids and a stigma. Asexual reproduction occurs by the formation of zoospores within the parent cell wall; sexual reproduction has not been observed. Species are distinguished from each other by their cell shape, number of contractile vacuoles and py ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
