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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 lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruddy Shelduck
The ruddy shelduck (''Tadorna ferruginea''), known in India as the Brahminy duck, is a bird species in the family Anatidae. It is a distinctive waterfowl, in length with a wingspan of . It has orange-brown body plumage with a paler head, while the tail and the flight feathers in the wings are black, contrasting with the white wing-coverts. It is a migratory bird, wintering in the Indian subcontinent and breeding in southeastern Europe and central Asia, though there are small resident populations in North Africa. It has a loud honking call. The ruddy shelduck mostly inhabits inland water-bodies such as lakes, reservoirs and rivers. The male and female form a lasting pair bond and the nest may be well away from water, in a crevice or hole in a cliff, tree or similar site. A clutch of about eight eggs is laid and is incubated solely by the female for about four weeks. The young are cared for by both parents and fledge about eight weeks after hatching. In central and eastern As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Shelduck
The common shelduck (''Tadorna tadorna'') is a waterfowl species of the shelduck genus, ''shelduck, Tadorna''. It is widespread and common in the Euro-Siberian region of the Palearctic realm, 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 Species description, formally named by the Swedish naturalist Carl Linnaeus in 1758 in the 10th edition of Systema Naturae, tenth edition of his ''Systema Naturae'' under the binomial nomenclature, binomial name ''Anas tadorna''. Linnaeus largely based his description o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological Type (biology), type wiktionary:en:specimen, specimen (or specimens). Article 67.1 A similar concept is used for suprageneric groups and called a type genus. In botanical nomenclature, these terms have no formal standing under the International Code of Nomenclature for algae, fungi, and plants, code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name with that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic grouping (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics, having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia (reptiles), which is paraphyletic with respect to birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Sequence
A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the nucleotides. By convention, sequences are usually presented from the 5' end to the 3' end. For DNA, with its double helix, there are two possible directions for the notated sequence; of these two, the sense strand is used. Because nucleic acids are normally linear (unbranched) polymers, specifying the sequence is equivalent to defining the covalent structure of the entire molecule. For this reason, the nucleic acid sequence is also termed the primary structure. The sequence represents genetic information. Biological deoxyribonucleic acid represents the information which directs the functions of an organism. Nucleic acids also have a secondary structure and tertiary structure. Primary structure is sometimes mistakenly referred to as "prim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome B
Cytochrome b is a protein found in the membranes of aerobic cells. In eukaryotic mitochondria (inner membrane) 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 a homologous 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 and function Cytochrome b/b6 is an integral membrane protein of approximately 400 amino acid residues that probably has 8 transmembrane segments. In plants and cyanobacteria, cytochrome b6 consists of two protein subunits encoded by the petB and petD genes. Cytochrome b/b6 non-covalently binds two heme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MtDNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in a eukaryotic cell; most of the DNA is in the cell nucleus, and, in plants and algae, the DNA also is found in plastids, such as chloroplasts. Mitochondrial DNA is responsible for coding of 13 essential subunits of the complex oxidative phosphorylation (OXPHOS) system which has a role in cellular energy conversion. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that human mtDNA has 16,569 base pairs and encodes 13 proteins. As in other vertebrates, the human mitochondrial genetic code differs slightly from nuclear DNA. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyletic
In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent common ancestor (or more precisely an ancestral population), i.e. excludes non-descendants of that common ancestor # the grouping contains all the descendants of that common ancestor, without exception Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic'' grouping meets 1. but not 2., thus consisting of the descendants of a common ancestor, excepting one or more monophyletic subgroups. A '' polyphyletic'' grouping meets neither criterion, and instead serves to characterize convergent relationships of biological features rather than genetic relationships – for example, night-active primates, fruit trees, or aquatic insects. As such, these characteristic features of a polyphyletic grouping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alopochen
''Alopochen'' is a genus of the bird family (biology), family Anatidae, part of the subfamily Tadorninae along with the shelducks. It contains one extant species, the Egyptian goose (''Alopochen aegyptiaca''), and three which became extinct in the last 1,000 years or so. The Egyptian goose is native to mainland Africa, and the recently extinct species are from Madagascar and the Mascarene Islands. mtDNA cytochrome b, cytochrome ''b'' DNA sequence, 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 a subspecies of ''A. mauritiana'') – Madagascar, Late Pleistocene: see Late Quaternary prehistoric birds * †Mauritius sheldgoose (''Alopochen mauritiana'') (Newton & Gadow 1893) – Mauritius, late 1690s * †Réunion sheldgoose or Kervazo's Eg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Madagascar
Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, fourth largest island, the List of island countries, second-largest island country, and the List of countries and dependencies by area, 46th largest country overall. Its capital and List of cities in Madagascar, largest city is Antananarivo. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from Africa during the Early Jurassic period, around 180 million years ago, and separated from the Indian subcontinent approximately 90 million years ago. This isolation allowed native plants and animals to evolve in relative seclusion; as a result, Madagascar is a biodiversity hotspot and one of the world's 17 megadiverse countries, with over 90% of its wildlife of Madagascar, wildlife being endemic. The island has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and recover. As a species' potential Range (biology), range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxon, Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the Fossil, fossil record) after a period of apparent absence. Over five billion species are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryotes globally, possibly many times more if microorganisms are included. Notable extinct animal species include Dinosaur, non-avian dinosaurs, Machairodontinae, saber-toothed cats, and mammoths. Through evolution, species arise through the process of specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
