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Shelduck
The shelducks, most species of which are found in the genus ''Tadorna'' (except for the Radjah shelduck, which is now found in its own monotypic genus ''Radjah''), are a group of large birds in the Tadorninae subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans. Biology Shelducks are a group of large, often semi-terrestrial waterfowl, which can be seen as intermediate between geese (''Anserinae'') and ducks. They are mid-sized (some 50–60 cm) Old World waterfowl. The sexes are colored slightly differently in most species, and all have a characteristic upperwing coloration in flight: the tertiary remiges form a green speculum, the secondaries and primaries are black, and the coverts (forewing) are white. Their diet consists of small shore animals ( winkles, crabs etc.) as well as grasses and other plants. They were originally known as "sheldrakes", which remained the most common name until the late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Shelduck
The common shelduck (''Tadorna tadorna'') is a waterfowl species of the shelduck genus, ''Tadorna''. It is widespread and common in the Euro-Siberian region of the Palearctic, mainly breeding in temperate and wintering in subtropical regions; in winter, it can also be found in the Maghreb. Fossil bones from Dorkovo (Bulgaria) described as ''Balcanas pliocaenica'' may actually belong to this species. More likely, they are an extinct species of ''Tadorna'' (if not a distinct genus) due to their Early Pliocene age; the present species is not unequivocally attested from the fossil record until some 2–3 million years later (Late Pliocene/ Early Pleistocene). Taxonomy The common shelduck was formally named by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his '' Systema Naturae'' under the binomial name ''Anas tadorna''. Linnaeus largely based his description on "The Sheldrake or Burrough-Duck" that had been described and illustrated in 1731 by the English ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Shelduck
The common shelduck (''Tadorna tadorna'') is a waterfowl species of the shelduck genus, ''Tadorna''. It is widespread and common in the Euro-Siberian region of the Palearctic, mainly breeding in temperate and wintering in subtropical regions; in winter, it can also be found in the Maghreb. Fossil bones from Dorkovo (Bulgaria) described as ''Balcanas pliocaenica'' may actually belong to this species. More likely, they are an extinct species of ''Tadorna'' (if not a distinct genus) due to their Early Pliocene age; the present species is not unequivocally attested from the fossil record until some 2–3 million years later (Late Pliocene/ Early Pleistocene). Taxonomy The common shelduck was formally named by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his '' Systema Naturae'' under the binomial name ''Anas tadorna''. Linnaeus largely based his description on "The Sheldrake or Burrough-Duck" that had been described and illustrated in 1731 by the English ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radjah Shelduck
The radjah shelduck (''Radjah radjah''), is a species of shelduck found mostly in New Guinea and Australia, and also on some of the Moluccas. It is known alternatively as the raja shelduck, black-backed shelduck, or in Australia as the Burdekin duck. Taxonomy The specific name ''radjah '' is from the Moluccan name ''Radja'' for the radjah shelduck on the island of Buru in Indonesia. Formerly placed in the genus ''Tadorna'', it differs markedly from other members in external morphology and mtDNA cytochrome ''b'' sequence data, suggesting its status should be reinvestigated.Sraml, M.; Christidis, L.; Easteal, S.; Horn, P. & Collet, C. (1996): Molecular Relationships Within Australasian Waterfowl (Anseriformes). ''Australian Journal of Zoology'' 44(1): 47–58. Current classification places it in its own monotypic genus ''Radjah''. Description Both the male and female of the species are mostly white, with dark wing-tips and a distinctive "collar" of dark feathers. Seen from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grass
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and pasture. The latter are commonly referred to collectively as grass. With around 780 genera and around 12,000 species, the Poaceae is the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae. The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, barley, and millet as well as feed for meat-producing animals. They provide, through direct human consumption, just over one-half (51%) of all dietary energy; rice provides 20%, wheat supplies 20%, maize (corn) 5.5%, and other grains 6%. Some members of the Poaceae are used as building materials (bamboo, thatch, and straw); others can provide a source of biofuel, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome B
Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes. Function In the mitochondrion of eukaryotes and in aerobic prokaryotes, cytochrome b is a component of respiratory chain complex III () — also known as the bc1 complex or ubiquinol-cytochrome c reductase. In plant chloroplasts and cyanobacteria, there is an analogous protein, cytochrome b6, a component of the plastoquinone-plastocyanin reductase (), also known as the b6f complex. These complexes are involved in electron transport, the pumping of protons to create a proton-motive force ( PMF). This proton gradient is used for the generation of ATP. These complexes play a vital role in cells. Structure Cytochrome b/b6 is an integral membrane protein of approximately 400 amino acid residues that probably has 8 transmembrane segments. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MtDNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus and, in plants and algae, also in plastids such as chloroplasts. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that the human mtDNA includes 16,569 base pairs and encodes 13 proteins. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits an examination of the relatedness of populations, and so has become important in anthropology and biogeography. Origin Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic groups are typically characterised by shared derived characteristics ( synapomorphies), which distinguish organisms in the clade from other organisms. An equivalent term is holophyly. The word "mono-phyly" means "one-tribe" in Greek. Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic group'' consists of all of the descendants of a common ancestor minus one or more monophyletic groups. A '' polyphyletic group'' is characterized by convergent features or habits of scientific interest (for example, night-active primates, fruit trees, aquatic insects). The features by which a polyphyletic group is differentiated from others are not inherited from a common ancestor. These definitions have tak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alopochen
''Alopochen'' is a genus of the bird family Anatidae, part of the subfamily Tadorninae along with the shelducks. It contains one extant species, the Egyptian goose (''Alopochen aegyptiaca''), and two or three species which became extinct in the last 1000 years or so. The Egyptian goose is native to mainland Africa, and the extinct species are from Madagascar and the Mascarene Islands. mtDNA cytochrome ''b'' sequence data suggest that the relationships of ''Alopochen'' to ''Tadorna'' need further investigation. Species * Egyptian goose, ''Alopochen aegyptiaca'' The extinct species of the genus are: * Malagasy shelduck or Madagascar shelduck, ''Alopochen sirabensis'' (Andrews 1897) (may be subspecies of ''A. mauritiana'') – Madagascar, prehistoric: see Late Quaternary prehistoric birds * Mauritius sheldgoose, ''Alopochen mauritiana'' (Newton & Gadow 1893)– Mauritius, late 1690s * Réunion sheldgoose or Kervazo's Egyptian goose, ''Alopochen kervazoi'' (Cowles 1994) Mourer-Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa across the Mozambique Channel. At Madagascar is the world's List of island countries, second-largest island country, after Indonesia. The nation is home to around 30 million inhabitants and consists of the island of Geography of Madagascar, Madagascar (the List of islands by area, fourth-largest island in the world), along with numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from the Indian subcontinent around 90 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, Madagascar is a biodiversity hotspot; over 90% of wildlife of Madagascar, its wildlife is endemic. Human settlement of Madagascar occurred during or befo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egyptian Goose
The Egyptian goose (''Alopochen aegyptiaca'') is a member of the duck, goose, and swan family Anatidae. It is native to Africa south of the Sahara and the Nile Valley. Egyptian geese were considered sacred by the Ancient Egyptians, and appeared in much of their artwork. Because of their popularity chiefly as an ornamental bird, escapees are common and feral populations have become established in Western Europe, the United States, and New Zealand. Taxonomy The Egyptian goose is believed to be most closely related to the shelducks (genus ''Tadorna'') and their relatives, and is placed with them in the subfamily Tadorninae. It is the only extant member of the genus ''Alopochen'', which also contains closely related prehistoric and recently extinct species. mtDNA cytochrome ''b'' sequence data suggest that the relationships of ''Alopochen'' to ''Tadorna'' need further investigation. Etymology The generic name ''Alopochen'' (literally, ''fox-goose'') is based on Greek (''alōpós ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harleian Library
The Harleian Library, Harley Collection, Harleian Collection and other variants ( la, Bibliotheca Harleiana) is one of the main "closed" collections (namely, historic collections to which new material is no longer added) of the British Library in London, formerly the library of the British Museum. The collection comprises 7,660 manuscripts, including 2,200 illuminated manuscripts, more than 14,000 original legal documents; and more than 500 rolls. It was assembled by Robert Harley (1661–1724) and his son Edward (1689–1741). In 1753, it was purchased for £10,000 by the British government. Together with the collections of Sir Robert Cotton (the Cotton library) and Hans Sloane (the Sloane library) it formed the basis of the British Museum's collection of manuscripts, which were transferred to the new British Library in 1973.British Library.History of the Harley Library. The collection contains illuminated manuscripts spanning the early Middle Ages to the Renaissance. There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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