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Swedish Blue Duck
The Swedish Blue ( sv, Svensk blå anka, italic=no) or Blue Swedish is a Swedish breed of domestic duck. It emerged during the nineteenth century in what was then Swedish Pomerania, located in present-day north-east Germany. History The Swedish Blue emerged during the nineteenth century in what was then Swedish Pomerania, now located in north-east Germany; the first documented mention is from 1835. Some birds were exported to the United States in 1884, and it was added to the Standard of Perfection of the American Poultry Association in 1904 as the "Swedish", with the single color variety "blue". The population of the Swedish Blue in Sweden consists of only 148 breeding birds; its conservation status worldwide was listed as "critical" by the Food and Agriculture Organization of the United Nations in 2007Barbara Rischkowsky, D. Pilling (eds.) (2007). [ftp://ftp.fao.org/docrep/fao/010/a1250e/annexes/List%20of%20breeds%20documented%20in%20the%20Global%20Databank%20for%20Animal%20G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domestic Duck
The domestic duck or domestic mallard (''Anas platyrhynchos domesticus'') is a subspecies of mallard that has been domesticated by humans and raised for meat, eggs, and down feathers. A few are also kept for show, as pets, or for their ornamental value. Almost all varieties of domesticated ducks, apart from the domestic Muscovy duck (''Cairina moschata''), are descended from the mallard. Domestication Whole-genome sequencing indicate that domestic ducks originate from a single domestication event of mallards during the Neolithic, followed by rapid selection for lineages favoring meat or egg production. They were likely domesticated in Southeast Asia (most likely Southern China) by the rice paddy-farming ancestors of modern Southeast Asians. The date of domestication is unknown due to the scarcity of archaeological records. They spread outwards from the region, first being mentioned in Han Chinese written records in central China by around 500 BC. Duck farming for both meat an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Feathers
Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tail are called rectrices (), singular rectrix (). The primary function of the flight feathers is to aid in the generation of both thrust and lift, thereby enabling flight. The flight feathers of some birds have evolved to perform additional functions, generally associated with territorial displays, courtship rituals or feeding methods. In some species, these feathers have developed into long showy plumes used in visual courtship displays, while in others they create a sound during display flights. Tiny serrations on the leading edge of their remiges help owls to fly silently (and therefore hunt more successfully), while the extra-stiff rectrices of woodpeckers help them to brace against tree trunks as they hammer on them. Even flightless birds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duck Breeds
Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form taxon; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species), since swans and geese are not considered ducks. Ducks are mostly aquatic birds, and may be found in both fresh water and sea water. Ducks are sometimes confused with several types of unrelated water birds with similar forms, such as loons or divers, grebes, gallinules and coots. Etymology The word ''duck'' comes from Old English 'diver', a derivative of the verb 'to duck, bend down low as if to get under something, or dive', because of the way many species in the dabbling duck group feed by upending; compare with Dutch and German 'to dive'. This word replaced Old English / 'duck', possibly to avoid confusion with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mendelian Proportion
Mendelian inheritance (also known as Mendelism) is a type of biological inheritance following the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 by Hugo de Vries and Carl Correns, and later popularized by William Bateson. These principles were initially controversial. When Mendel's theories were integrated with the Boveri–Sutton chromosome theory of inheritance by Thomas Hunt Morgan in 1915, they became the core of classical genetics. Ronald Fisher combined these ideas with the theory of natural selection in his 1930 book ''The Genetical Theory of Natural Selection'', putting evolution onto a mathematical footing and forming the basis for population genetics within the modern evolutionary synthesis. History The principles of Mendelian inheritance were named for and first derived by Gregor Johann Mendel, a nineteenth-century Moravian monk who formulated his ideas after conducting simple hybridisation experiments with pea plants (' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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