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Tardigrade
Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them Kleiner Wasserbär ("little water bear"). In 1777, the Italian biologist Lazzaro Spallanzani named them Tardigrada (), which means "slow steppers". They have been found in diverse regions of Earth's biospheremountaintops, the deep sea, tropical rainforests, and the Antarctic. Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions – such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation – that would quickly kill most other known forms of life. Tardigrades have survived exposure to outer space. There are about 1,300 known species in the phylum Tardigrada, a part of the superphylum Ecdysozoa consisting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milnesium Tardigradum
''Milnesium tardigradum'' is a cosmopolitan species of tardigrade that can be found in a diverse range of environments. It has also been found in the sea around Antarctica. ''M. tardigradum'' was described by Louis Michel François Doyère in 1840. It contains unidentified osmolytes that could potentially provide important information in the process of cryptobiosis. Description Morphology ''M. tardigradum'' has a symmetrical body with a total of eight legs; it uses claws—a distinctive feature for this tardigrade species. The total length of the body varies, with some measuring up to 0.7 mm in length. ''M. tardigradum'' have been found to possess a high level of radioresistance. In 2007, individuals of two tardigrade species, '' Richtersius coronifer'' and ''M. tardigradum'', were subject to the radiation, near-vacuum, and near-absolute zero conditions of outer space as part of the European Space Agency's Biopan-6 experiment. Three specimens of ''M. tardigradum'' surviv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutardigrade
Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendices. Primarily freshwater bound, some species have secondarily gained the ability to live in marine environments ('' Halobiotus''). By cryptobiosis many species are able to live temporarily in very dry environments. More than 700 species have been described. The order Apochela consists of only one family, Milnesiidae, with two genera: '' Milnesium'' and '' Limmenius''. ''Milnesium tardigradum'' can be found worldwide and is one of the biggest species among tardigrades (up to 1.4 mm); similar-looking species have been found in Cretaceous amber. The mouth of this predator has a wide opening, so the animal can eat rotifers and larger protist A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exclu ...s. Other eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutardigrada
Eutardigrada are a class of tardigrades (Tardigrada) without lateral appendices. Primarily freshwater bound, some species have secondarily gained the ability to live in marine environments ('' Halobiotus''). By cryptobiosis many species are able to live temporarily in very dry environments. More than 700 species have been described. The order Apochela consists of only one family, Milnesiidae, with two genera: '' Milnesium'' and '' Limmenius''. ''Milnesium tardigradum'' can be found worldwide and is one of the biggest species among tardigrades (up to 1.4 mm); similar-looking species have been found in Cretaceous amber. The mouth of this predator has a wide opening, so the animal can eat rotifers and larger protist A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exclu ...s. Other eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotardigrade
The class Heterotardigrada includes tardigrades (water bears) that have cephalic appendages and legs with four separate but similar digits or claws on each. 444 species have been described. Anatomy The anatomy of the reproductive system is an important defining feature in distinguishing the different groups of tardigrades. Heterotardigrades have gonoducts that open to the outside through a preanal gonopore, rather than opening into the rectum as in the only other confirmed class of tardigrades, the Eutardigrada. The third class, Mesotardigrada Mesotardigrada is one of three classes of tardigrades, consisting of a single species, ''Thermozodium esakii''. The animal reportedly has six claws of equal length at each foot. This species was described in 1937 by German zoologist Gilbert Ra ..., is represented by a single species known from a single specimen that is now lost, and the location from which that specimen was collected has since been destroyed by an earthquake, so its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotardigrada
The class Heterotardigrada includes tardigrades (water bears) that have cephalic appendages and legs with four separate but similar digits or claws on each. 444 species have been described. Anatomy The anatomy of the reproductive system is an important defining feature in distinguishing the different groups of tardigrades. Heterotardigrades have gonoducts that open to the outside through a preanal gonopore, rather than opening into the rectum as in the only other confirmed class of tardigrades, the Eutardigrada. The third class, Mesotardigrada Mesotardigrada is one of three classes of tardigrades, consisting of a single species, ''Thermozodium esakii''. The animal reportedly has six claws of equal length at each foot. This species was described in 1937 by German zoologist Gilbert Ra ..., is represented by a single species known from a single specimen that is now lost, and the location from which that specimen was collected has since been destroyed by an earthquake, so its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesotardigrada
Mesotardigrada is one of three classes of tardigrades, consisting of a single species, ''Thermozodium esakii''. The animal reportedly has six claws of equal length at each foot. This species was described in 1937 by German zoologist Gilbert Rahm from a hot spring near Nagasaki, Japan. The inability of taxonomists to replicate Rahm's finding has cast doubt on the accuracy of the description, making ''T. esakii'', and by extension the entire class Mesotardigrada, a ''taxon inquirendum''. Taxonomic ambiguity The type specimen Rahm used as the basis of his description has either been lost or it was never preserved in the first place, which Grothman ''et al''. (2017) suggest is consistent with the lax taxonomic standards of the 1930s. Thus, re-examination of the original specimen is not possible. Complicating matters further, the type locality from which Rahm collected his specimen may have been destroyed by an earthquake and subsequent searches for additional specimens matching ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann August Ephraim Goeze
Johann August Ephraim Goeze (; 28 May 1731 – 27 June 1793) was a German zoologist, born in Aschersleben. He is known for the discovery of tardigrades, also called water bears. He was the son of Johann Heinrich and Catherine Margarete (née Kirchhoff). He studied theology at University of Halle. He married Leopoldine Maria Keller in 1770, by whom he had four children. In 1751, he became a pastor in Aschersleben, in Quedlinburg, and later of in Quedlinburg in 1762, finally becoming first deacon of the seminary of Quedlinburg in 1787. He died in Quedlinburg. He did much work with aquatic invertebrates, particularly insects and worms. In 1773, he was the first to describe tardigrades. In 1784, Goeze perceived the similarities between the heads of tapeworms found in the human intestinal tract and the invaginated heads of ''Cysticercus cellulosae'' in pigs. Works *Goeze, J. A. E. 1776. Verzeichnisse der Namen von Insecten und Wurmern, welche in dem Rosel, Kleemann und De Geer vorko ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echiniscus
''Echiniscus'' is a genus of tardigrade Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them Kleiner Wasserbär ...s in the family Echiniscidae. The genus was named and described by Karl August Sigismund Schultze in 1840. Species The genus includes the following species: * '' Echiniscus africanus'' Murray, 1907 * '' Echiniscus aliquantillus'' Grigarick, Schuster & Nelson, 1983 * '' Echiniscus angolensis'' da Cunha & do Nascimento Ribeiro, 1964 * '' Echiniscus apuanus'' Bertolani, 1946 * '' Echiniscus arcangelii'' Maucci, 1973–74 * '' Echiniscus arctomys'' Ehrenberg, 1853 * '' Echiniscus arthuri'' Pilato, Binda & Lisi, 2005 * '' Echiniscus azoricus'' Fontoura, Pilato & Lisi, 2008 * '' Echiniscus baius'' Marcus, 1928 * '' Echiniscus baloghi'' Iharos, 1973 * '' Echiniscus barbarae'' Kaczmarek & Michal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecdysozoa
Ecdysozoa () is a group of protostome animals, including Arthropoda ( insects, chelicerata, crustaceans, and myriapods), Nematoda, and several smaller phyla. They were first defined by Aguinaldo ''et al.'' in 1997, based mainly on phylogenetic trees constructed using 18S ribosomal RNA genes. A large study in 2008 by Dunn ''et al.'' strongly supported the Ecdysozoa as a clade, that is, a group consisting of a common ancestor and all its descendants. The group is also supported by morphological characters, and includes all animals that grow by ecdysis, moulting their cuticle. The group was initially contested by a significant minority of biologists. Some argued for groupings based on more traditional taxonomic techniques, while others contested the interpretation of the molecular data. Etymology The name ''Ecdysozoa'' stems etymologically . Characteristics The most notable characteristic shared by ecdysozoans is a three-layered cuticle (four in Tardigrada) composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broad range of environments. Less formally, they are categorized as Helminths, but are taxonomically classified along with arthropods, tardigrades and other moulting animals in the clade Ecdysozoa, and unlike flatworms, have tubular digestive systems with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species described to date vary by author and may change rapidly over time. A 2013 survey of animal biodiversity published in the mega ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outer Space
Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is . The plasma between galaxies is thought to account for about half of the baryonic (ordinary) matter in the universe, having a number density of less than one hydrogen atom per cubic metre and a kinetic temperature of millions of kelvins. Local concentrations of matter have condensed into stars and galaxies. Studies indicate that 90% of the mass in most galaxies is in an unknown form, called dark matter, which interacts with other matter through gravitational but not electromagnetic forces. Observa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
