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Rotifer Genera
The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals. They were first described by 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 saltwater species. Some rotifers are free swimming and truly planktonic, others move by inchworming along a substrate, and some are sessile, living inside tubes or gelatinous 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 species also contributing to the decomposition of soil organic matter. Most species of the roti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georges Cuvier
Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French natural history, naturalist and zoology, zoologist, sometimes referred to as the "founding father of paleontology". Cuvier was a major figure in natural sciences research in the early 19th century and was instrumental in establishing the fields of comparative anatomy and paleontology through his work in comparing living animals with fossils. Cuvier's work is considered the foundation of vertebrate paleontology, and he expanded Linnaean taxonomy by grouping classes into phylum, phyla and incorporating both fossils and living species into the classification. Cuvier is also known for establishing extinction as a fact—at the time, extinction was considered by many of Cuvier's contemporaries to be merely controversial speculation. In his ''Essay on the Theory of the Earth'' (1813) Cuvier proposed that now-extinct species had been wiped out by periodic catastrophi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish and whales. Marine plankton include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in the freshwaters of lakes and rivers. Plankton are usually thought of as inhabiting water, but there are also airborne versions, the aeroplankton, that live part of their lives drifting in the atmosphere. These include plant spores, pollen and wind-scattered seeds, as well as microorganisms swept into the air from terrestrial dust storms and oceanic plankton swept into the air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use. Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as bacterial strains or plant varieties), that is complex but it is not a species complex. A species complex is in most cas ... [...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 In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ... family Lecanidae and has a cosmopolitan distribution Species The following species are recognised in the genus ''Colurella'': *'' 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'' * ... [...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). Reproduction ''Brachionus calyciflorus'' normally reproduces by cyclical parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development .... Transitions to obligate parthenogenesis have been described. Obligate parthenogens were homozygous for a recessive allele, which caused inability to respond to the chemical signals that normally induce sexual reproduction in this species. Species complex Like the ''Brachionus plicatilis'' cryptic species complex ''Brachionus c ... [...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. 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'' species complex range at least from 0.056 to 0.416 pg. The complete mitochondrial genome of B. plicatilis sensu stricto NH1L has been sequenced. Cryptic species complex Brachionus plicatilis strains have long been divided into ‘L-’ and ‘S-type ... [...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 ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Baikal
Lake Baikal (, russian: Oзеро Байкал, Ozero Baykal ); mn, Байгал нуур, Baigal nuur) is a rift lake in Russia. It is situated in southern Siberia, between the federal subjects of Irkutsk Oblast to the northwest and the Republic of Buryatia to the southeast. With of water, Lake Baikal is the world's largest freshwater lake by volume, containing 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 deepest lake, with a maximum depth of , and the world's oldest lake, at 25–30 million years. At —slightly larger than Belgium—Lake Baikal is the world's seventh-largest lake by surface area. It is among the world's clearest lakes. Lake Baikal is home to thousands of species of plants and animals, many of them endemic to the region. It is also home to Buryat tribes, who raise goats, camels, cattle, sheep, and horses on the eastern side of the lake, where the mean temperature var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalodella Vittata
''Cephalodella'' is a genus of rotifers in the family Notommatidae. '' Cephalodella vittata'' is a species endemic to Lake Baikal Lake Baikal (, russian: Oзеро Байкал, Ozero Baykal ); mn, Байгал нуур, Baigal nuur) is a rift lake in Russia. It is situated in southern Siberia, between the federal subjects of Irkutsk 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-list of the marine species i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemism
Endemism is the state of a species being found 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 be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmopolitan Distribution
In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The extreme opposite of a cosmopolitan species is an endemic one, being found only in a single geographical location. Qualification The caveat “in appropriate habitat” is used to qualify the term "cosmopolitan distribution", excluding in most instances polar regions, extreme altitudes, oceans, deserts, or small, isolated islands. For example, the housefly is highly cosmopolitan, yet is neither oceanic nor polar in its distribution. Related terms and concepts The term pandemism also is in use, but not all authors are consistent in the sense in which they use the term; some speak of pandemism mainly in referring to diseases and pandemics, and some as a term intermediate between endemism and cosmopolitanism, in effect regarding pandemism as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zooplankton
Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers. Zooplankton can be contrasted with phytoplankton, which are the plant component of the plankton community ("phyto" comes from the Greek word for ''plant''). Zooplankton are heterotrophic (other-feeding), whereas phytoplankton are autotrophic (self-feeding). This means zooplankton cannot manufacture their own food but must eat other plants or animals instead — in particular they eat phytoplankton. Zooplankton are generally larger than phytoplankton, most are microscopic, but some (such as jellyfish) are macroscopic and can be seen with the naked eye. Many protozoans (single-celled protists that prey on other microscopic life) are zooplankton, including zooflagellates, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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