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Myopus
The wood lemming (''Myopus schisticolor'') is a species of rodent in the family Cricetidae. It belongs to the rodent subfamily Arvicolinae, so is a relative of the voles, lemmings, and muskrats. It is found in the taiga biome of China, Estonia, Finland, Mongolia, Norway, Russia, and Sweden. Sex determination Wood lemmings produce about three times as many female as male offspring. This is due to an unusual genetic system where they have two different types of X chromosomes, the normal X and a mutated X*. Females with that mutation on their X*-chromosome inhibit the male determining effect of the Y chromosome. This leads to three genetic types of females: XX, X*X and X*Y and one genetic type of males XY. The X*Y females are fertile, but only produce X* ova, which means they only produce female offspring. It is not fully known the extent to which nature balances out the differences in the adult population, but sampling studies seem to suggest males do make up as little as 25% of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lemmini
Lemmini is a tribe of lemmings in the subfamily Arvicolinae. Species in this tribe are: Tribe Lemmini * Genus ''Lemmus'' - true lemmings ** Amur lemming (''L. amurensis'') ** Norway lemming (''L. lemmus'') ** Beringian lemming (''L. nigripes'') ** East Siberian lemming (''L. paulus'') ** West Siberian lemming (''L. sibiricus'') ** North American brown lemming (''L. trimucronatus'') * Genus ''Myopus'' - wood lemming ** Wood lemming (''M. schisticolor'') * Genus '' Synaptomys'' - bog lemmings ** Northern bog lemming (''S. borealis'') ** Southern bog lemming (''S. cooperi'') The fossil taxa '' Mictomys'', '' Tobienia'' (both thought to be allied with ''Synaptomys''), and '' Plioctomys'' (thought to be allied with ''Lemmus'' and ''Myopus'') are also thought to belong to this group. A 2021 phylogenetic study using mtDNA recovered Lemmini as being the most basal clade of the Arvicolinae, diverging during the late Miocene The Miocene ( ) is the first geological epoch of the Neog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arvicolinae
The Arvicolinae are a subfamily of rodents that includes the voles, lemmings, and muskrats. They are most closely related to the other subfamilies in the Cricetidae (comprising the hamsters and New World rats and mice). Some authorities place the subfamily Arvicolinae in the family Muridae along with all other members of the superfamily Muroidea. Some refer to the subfamily as the Microtinae (yielding the adjective "microtine") or rank the taxon as a full family, the Arvicolidae. The Arvicolinae are the most populous group of Rodentia in the Northern Hemisphere. They often are found in fossil occlusions of bones cached by past predators such as owls and other birds of prey. Fossils of this group are often used for biostratigraphic dating of paleontological and archeological sites in North America and Europe. Description The most convenient distinguishing feature of the Arvicolinae is the nature of their molar teeth, which have prismatic cusps in the shape of alternati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lemming
A lemming is a small rodent, usually found in or near the Arctic in tundra biomes. Lemmings form the subfamily Arvicolinae (also known as Microtinae) together with voles and muskrats, which form part of the superfamily Muroidea, which also includes rats, mice, hamsters, and gerbils. In popular culture, a longstanding myth holds that they exhibit herd mentality and jump off cliffs, committing mass suicide. Description and habitat Lemmings measure around in length and weigh around . Lemmings are quite rounded in shape, with brown and black, long, soft fur. They have a very short tail, a stubby, hairy snout, short legs, and small ears. They have a flattened claw on the first digit of their front feet, which helps them to dig in the snow. They are herbivorous, feeding mostly on mosses and grasses. They also forage through the snow surface to find berries, leaves, shoots, roots, bulbs, and lichens. Lemmings choose their preferred dietary vegetation disproportionately to its occurrenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerrit Smith Miller Jr
Gerrit is a Dutch male name meaning "''brave with the spear''", the Dutch and Frisian form of Gerard. People with this name include: * Gerrit Achterberg (1905–1962), Dutch poet * Gerrit van Arkel (1858–1918), Dutch architect * Gerrit Badenhorst (born 1962), South African powerlifter and professional strongman competitor * Gerrit Battem (c. 1636 – 1684), Dutch landscape painter * Gerrit Beneker (1882–1934), American painter and illustrator * Gerrit Berckheyde (1638–1698), Dutch painter * Gerrit Berkhoff (1901–1996), Dutch chemist and university rector * Gerrit Cornelis Berkouwer (1903–1996), Dutch theologian * Gerrit Berveling (born 1944), Dutch Esperanto author * Gerrit Blaauw (born 1924), Dutch computer engineer * Gerrit de Blanken (1894–1961), Dutch pottery artist * Gerrit van Bloclant (1578–1650), Dutch Renaissance painter * Gerrit Bol (1906–1989), Dutch mathematician * Gerrit Braamcamp (1699–1771), Dutch distiller, timber merchant and art collector * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Described In 1844
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fauna Of Scandinavia
Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is ''funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoologists and paleontologists use ''fauna'' to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess Shale fauna". Paleontologists sometimes refer to a sequence of faunal stages, which is a series of rocks all containing similar fossils. The study of animals of a particular region is called faunistics. Etymology ''Fauna'' comes from the name Fauna, a Roman goddess of earth and fertility, the Roman god Faunus, and the related forest spirits called Fauns. All three words are cognates of the name of the Greek god Pan, and ''panis'' is the Greek equivalent of fauna. ''Fauna'' is also the word for a book that catalogues the animals in such a manner. The term was first used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermogenesis
Thermogenesis is the process of heat production in organisms. It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage, the Voodoo lily (''Sauromatum venosum''), and the giant water lilies of the genus ''Victoria''. The lodgepole pine dwarf mistletoe, ''Arceuthobium americanum'', disperses its seeds explosively through thermogenesis.Rolena A.J. deBruyn, Mark Paetkau, Kelly A. Ross, David V. Godfrey & Cynthia Ross Friedman (2015)"Thermogenesis-triggered seed dispersal in dwarf mistletoe" Types Depending on whether or not they are initiated through locomotion and intentional movement of the muscles, thermogenic processes can be classified as one of the following: * Exercise-associated thermogenesis (EAT) * Non-exercise activity thermogenesis (NEAT), energy expended for everything that is not sleeping, eating or sports-like exercise. * Diet-induced thermogenesis (DIT) Shivering One method to raise temperature is thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kamchatka Peninsula
The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and western coastlines, respectively. Immediately offshore along the Pacific coast of the peninsula runs the Kuril–Kamchatka Trench. The Kamchatka Peninsula, the Commander Islands, and the Karaginsky Island, constitute the Kamchatka Krai of the Russia, Russian Federation. The vast majority of the 322,079 inhabitants are ethnic Russians, although about 13,000 are Koryaks (2014). More than half of the population lives in Petropavlovsk-Kamchatsky (179,526 in 2010) and nearby Yelizovo (38,980). The Kamchatka peninsula contains the volcanoes of Kamchatka, a World Heritage Site, UNESCO World Heritage Site. Geography Politically, the peninsula forms part of Kamchatka Krai. The southern tip is called Cape Lopatka. (Lopatka is Russian for s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaccinium
''Vaccinium'' is a common and widespread genus of shrubs or dwarf shrubs in the heath family (Ericaceae). The fruits of many species are eaten by humans and some are of commercial importance, including the cranberry, blueberry, bilberry (whortleberry), lingonberry (cowberry), and huckleberry. Like many other ericaceous plants, they are generally restricted to acidic soils. Description The plant structure varies between species: some trail along the ground, some are dwarf shrubs, and some are larger shrubs perhaps tall. Some tropical species are epiphytic. Stems are usually woody. Flowers are epigynous with fused petals, and have long styles that protrude from their bell-shaped corollas. Stamens have anthers with extended tube-like structures called "awns" through which pollen falls when mature. Inflorescences can be axillary or terminal. The fruit develops from an inferior ovary, and is a four- or five-parted berry; it is usually brightly coloured, often being red or bluish wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deschampsia
''Deschampsia'' is a genus of plants in the grass family, commonly known as hair grass or tussock grass. The genus is widespread across many countries.Palisot de Beauvois, Ambroise Marie François Joseph. 1812. Essai d'une Nouvelle Agrostographie 91 descriptions in Latin, etymology explained in French The genus is named for French physician and naturalist Louis Auguste Deschamps (1765–1842). ''Deschampsia'' species are used as food plants by the e of some species of , including |
Pleurozium Schreberi
''Pleurozium schreberi'', the red-stemmed feathermoss or Schreber's big red stem moss, is a moss with a loose growth pattern. The root name ''pleuro'' comes from the Latin for ribs, possibly describing how the parts branch from the stem. The species occurs on the floor of the boreal forests of Canada, Scandinavia and northern Russia; an example of this occurrence is within the black spruce/feathermoss climax forest, sometimes having moderately dense overstory canopy and featuring a forest floor of feathermosses including, ''Hylocomium splendens'' and ''Ptilium crista-castrensis''.C. Michael Hogan. 2008''Black Spruce: Picea mariana'', GlobalTwitcher.com, ed. Nicklas Stromberg In a study of the effect of the herbicide Asulam on moss growth, ''Pleurozium schreberi'' was shown to have intermediate sensitivity to Asulam exposure. Gallery Image:PleuroziumPiceaBorealForest.JPG, ''Pleurozium schreberi'' carpeting the floor of black spruce (''Picea mariana'') and balsam fir (''Abies ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
