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Rotifer Genera
The rotifers (, from Latin 'wheel' and 'bearing'), sometimes called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic Coelom#Pseudocoelomates, pseudocoelomate animals. They were first described by John Harris (writer), Rev. John Harris in 1696, and other forms were described by Antonie van Leeuwenhoek in 1703. Most rotifers are around long (although their size can range from to over ), and are common in freshwater environments throughout the world with a few Seawater, saltwater species. Some rotifers are free swimming and truly planktonic, others move by inchworming along a substrate, and some are Sessility (zoology), sessile, living inside tubes or gelatinous holdfast (biology), holdfasts that are attached to a substrate. About 25 species are colonial (e.g., ''Sinantherina semibullata''), either sessile or planktonic. Rotifers are an important part of the freshwater zooplankton, being a major foodsource and with many specie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bdelloidea
Bdelloidea (from Greek language, Greek βδέλλα, ''bdella'' 'leech') is a Class (biology), class of rotifers found in freshwater habitats all over the world. There are over 450 described species of bdelloid rotifers (or 'bdelloids'), distinguished from each other mainly on the basis of Morphology (biology), morphology. The main characteristics that distinguish bdelloids from #Evolutionary Relationships, related groups of rotifers are exclusively parthenogenesis, parthenogenetic reproduction and the ability to survive in dry, harsh environments by entering a state of desiccation-induced dormancy (anhydrobiosis) at any life stage. They are often referred to as "ancient asexuals" due to their unique asexual history that spans back to over 25 million years ago through fossil evidence. Bdelloid rotifers are microscopic organisms, typically between 150 and 700 μm in length. Most are slightly too small to be seen with the naked eye, but appear as tiny white dots through even ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seawater
Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately of dissolved salts (predominantly sodium () and chloride () ions). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at ) because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about . The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was . Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measuremen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lecane Bulla
''Lecane'' is a genus of rotifers belonging to the family Lecanidae. It is the only genus in the monotypic family Lecanidae and has a cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ... Species The following species are recognised in the genus ''Lecane'': *'' Lecane abanica'' *'' Lecane acanthinula'' *'' Lecane aculeata'' *'' Lecane acus'' *'' Lecane aeganea'' *'' Lecane affinis'' *'' Lecane agilis'' *'' Lecane althausi'' *'' Lecane amazonica'' *'' Lecane arcuata'' *'' Lecane arcula'' *'' Lecane armata'' *'' Lecane aspasia'' *'' Lecane asymmetrica'' *'' Lecane baimaii'' *'' Lecane balatonica'' *'' Lecane batillifer'' *'' Lecane bidactyla'' *'' Lecane bifastigata'' *'' Lecane bifurca'' *'' Lecane blachei'' *'' Lecane boettgeri'' *'' L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachionus Calyciflorus
''Brachionus calyciflorus'' is a planktonic rotifer species occurring in freshwater. It is commonly used as a model organism in toxicology, ecology and evolutionary biology. Its advantages include the small size and short generation time (average generation time of ''B. calyciflorus'' is around 2.2 days at 24 °C). Taxonomy The taxonomy of Brachionus calyciflorus is well-established based on morphological and molecular characteristics. As a member of the phylum Rotifera, it shares many features with other rotifers, including a ciliated corona and a characteristic rotary motion. Within the genus Brachionus, there are several species, including B. plicatilis, which is also commonly used in research and aquaculture. Brachionus calyciflorus is distinct from other species in the genus due to its unique calyx-shaped lorica. Morphology Brachionus calyciflorus has a characteristic morphology that distinguishes it from other rotifer species. The body of Brachionus calyciflorus is elo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachionus Plicatilis
''Brachionus plicatilis'' is a euryhaline (tolerate a wide range of salinity) rotifer in the family '' Brachionidae'', and is possibly the only commercially important rotifer, being raised in the aquaculture industry as food for fish larvae. It has a broad distribution in salt lakes around the world and has become a model system for studies in ecology and evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re .... Reproduction ''Brachionus'' species can normally reproduce asexually and sexually (cyclical parthenogenesis). Sexual reproduction (termed Mixis) is usually induced when population density increases. Mixis in Brachionus plicatilis has been shown to be induced by a density-dependent chemical cue. Genome size Haploid '1C' genome sizes in the ''Brachionus plicatilis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Barcoding
DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections (also called " sequences"), an individual sequence can be used to uniquely identify an organism to species, just as a supermarket scanner uses the familiar black stripes of the UPC barcode to identify an item in its stock against its reference database. These "barcodes" are sometimes used in an effort to identify unknown species or parts of an organism, simply to catalog as many taxa as possible, or to compare with traditional taxonomy in an effort to determine species boundaries. Different gene regions are used to identify the different organismal groups using barcoding. The most commonly used barcode region for animals and some protists is a portion of the cytochrome ''c'' oxidase I (COI or COX1) gene, found in mitochondrial DNA. Other genes suitable for DNA barcoding a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Baikal
Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia between the Federal subjects of Russia, federal subjects of Irkutsk Oblast, Irkutsk Oblasts of Russia, Oblast to the northwest and the Republic of Buryatia to the southeast. At —slightly larger than Belgium—Lake Baikal is the world's List of lakes by area, seventh-largest lake by surface area, as well as the second largest lake in Eurasia after the Caspian Sea. However, because it is also the List of lakes by depth, deepest lake, with a maximum depth of , Lake Baikal is the world's List of lakes by volume, largest freshwater lake by volume, containing of water or 22–23% of the world's fresh surface water, more than all of the North American Great Lakes combined. It is also the world's ancient lake, oldest lake at 25–30 million years, and among the clearest. It is estimated that the lake contains around 19% of the unfrozen fresh water on the planet. Lake Baikal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalodella Vittata
''Cephalodella'' is a genus of rotifers in the family Notommatidae, with 190 species worldwide. '' Cephalodella vittata'' is a species endemic to Lake Baikal Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia between the Federal subjects of Russia, federal subjects of Irkutsk Oblast, Irkutsk Oblasts of Russia, Oblast to the northwest and the Repu ....Hendrik Segers (2007). Annotated checklist of the rotifers (Phylum Rotifera), with notes on nomenclature, taxonomy Selected species * '' Cephalodella auritculata'' * '' Cephalodella catellina'' * '' Cephalodella elegans'' * '' Cephalodella forficata'' * '' Cephalodella forficula'' * '' Cephalodella gibba'' (Ehrenberg, 1830) * '' Cephalodella hoodi'' * '' Cephalodella marina'' Myers, 1924 * '' Cephalodella sterea'' * '' Cephalodella vittata'' References * O'Reilly, M. (2001). Rotifera, in: Costello, M.J. et al. (Ed.) (2001). European register of marine species: a check- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmopolitan Distribution
In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and environmental conditions, though this is not always so. Killer whales ( orcas) are among the most well-known cosmopolitan species on the planet, as they maintain several different resident and transient (migratory) populations in every major oceanic body on Earth, from the Arctic Circle to Antarctica and every coastal and open-water region in-between. Such a taxon (usually a species) is said to have a ''cosmopolitan'' distribution, or exhibit cosmopolitanism, as a species; another example, the rock dove (commonly referred to as a ' pigeon'), in addition to having been bred domestically for centuries, now occurs in most urban areas around the world. The extreme opposite of a cosmopolitan species is an endemic (native) species, or one foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zooplankton
Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequently, they drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers. Zooplankton can be contrasted with phytoplankton (cyanobacteria and microalgae), which are the plant-like component of the plankton community (the " phyto-" prefix comes from , although taxonomically ''not'' plants). Zooplankton are heterotrophic (other-feeding), whereas phytoplankton are autotrophic (self-feeding), often generating biological energy and macromolecules through chlorophyllic carbon fixation using sunlightin other words, zooplankton cannot manufacture their own food, while phytoplankton can. As a result, zooplankton must acquire nutrients by feeding on other organisms such as phytoplankton, which are generally smaller t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinantherina Semibullata
''Sinantherina'' is a genus of rotifers belonging to the family Flosculariidae. The genus has almost cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en .... Species: *'' Sinantherina ariprepes'' *'' Sinantherina procera'' *'' Sinantherina semibullata'' *'' Sinantherina socialis'' *'' Sinantherina spinosa'' *'' Sinantherina triglandularis'' References {{Taxonbar, from=Q4179687 Rotifers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
