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Anas Moschata
The Muscovy duck (''Cairina moschata'') is a large duck native to the Americas, from the Rio Grande Valley of Texas and Mexico south to Argentina and Uruguay. Small wild and feral breeding populations have established themselves in the United States, particularly in Florida, Louisiana, Massachusetts, the Big Island of Hawaii, as well as in many other parts of North America, including southern Canada. Feral Muscovy ducks are found in New Zealand, Australia, and in parts of Europe. It is a large duck, with the males about long, and weighing up to . Females are noticeably smaller, and only grow to , roughly half the males' size. The bird is predominantly black and white, with the back feathers being iridescent and glossy in males, while the females are more drab. The amount of white on the neck and head is variable, as well as the bill, which can be yellow, pink, black, or any mixture of these colors. It may have white patches or bars on the wings, which become more noti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Fleming (naturalist)
John Fleming FRSE FRS FSA (10 January 1785 – 18 November 1857) was a Scottish Free Church minister, naturalist, zoologist and geologist. He named and described a number of species of molluscs. During his life he tried to reconcile theology with science. Fleming Fjord in Greenland was named after him. Life He was born on Kirkroads Farm near Bathgate in Linlithgowshire, the son of Alexander Fleming and his wife Catherine Nimmo. After studying divinity at the University of Edinburgh he graduated in 1805. He was licensed to preach by the Church of Scotland and ordained as minister of Bressay in the Shetland Islands in 1808. In 1810 he translated to the parish of Flisk in Fife and in 1832 translated to Clackmannan. In 1808, he participated in founding the Wernerian Society, a learned society devoted to the study of natural history. John Fleming became a Member of the Royal Society of London on 25 February 1813 (he was not granted Fellowship). In 1814, he was awarded an hon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Culinary
Culinary arts are the cuisine arts of outline of food preparation, food preparation, cooking and food presentation, presentation of food, usually in the form of meals. People working in this field – especially in establishments such as restaurants – are commonly called chefs or Cook (profession), cooks, although, at its most general, the terms culinary artist and culinarian are also used. Table manners (the table arts) are sometimes referred to as a culinary art. Expert chefs are in charge of making meals that are both aesthetically beautiful and delicious, which requires understanding of food science, nutrition, and diet. Delicatessens and relatively large institutions like hotels and hospitals rank as their principal workplaces after restaurants. History The origins of culinary arts began with primitive humans roughly 2 million years ago. Various theories exist as to how early humans used fire to cook meat. According to anthropologist Richard Wrangham, author of ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submetacentric
The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore. The physical role of the centromere is to act as the site of assembly of the kinetochores – a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation – i.e. binding microtubules and signaling to the cell cycle machinery when all chromosomes have adopted correct attachments to the spindle, so that it is safe for cell division to proceed to completion and for cells to enter anaphase. There are, broadly speaking, two types of centromeres. "Point centromeres" bind to specific proteins that recognize particular DNA sequences with high efficiency. Any piece of DNA with the point centromere DNA sequence on it will typically form a centromere if pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex Chromosome
A sex chromosome (also referred to as an allosome, heterotypical chromosome, gonosome, heterochromosome, or idiochromosome) is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical pair of mammal allosomes, determine the sex of an individual created in sexual reproduction. Autosomes differ from allosomes because autosomes appear in pairs whose members have the same form but differ from other pairs in a diploid cell, whereas members of an allosome pair may differ from one another and thereby determine sex. Nettie Stevens and Edmund Beecher Wilson both independently discovered sex chromosomes in 1905. However, Stevens is credited for discovering them earlier than Wilson. Differentiation In humans, each cell nucleus contains 23 pairs of chromosomes, a total of 46 chromosomes. The first 22 pairs are called autosomes. Autosomes are homologous chromosomes i.e. chromosomes which contain the same genes (regions of DNA) i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microchromosome
A microchromosome (μChr) is a type of very small chromosome which is a typical component of the karyotype of birds, some reptiles, fish, and amphibians; they have yet to be found in mammals. They are less than 20 Mb in size; chromosomes which are greater than 40 Megabase, Mb in size are known as macrochromosomes (MChrs), while those between 20 and 40 Mb are classified as intermediate chromosomes. Microchromosomes are characteristically very small and often cytogenetically indistinguishable in a karyotype. While originally thought to be insignificant fragments of chromosomes, in species where they have been studied they have been found to be rich in genes and high in GC content. In chickens, microchromosomes have been estimated to contain between 50 and 75% of all genes. The presence of microchromosomes makes ordering and identifying chromosomes into a coherent karyotype particularly difficult. During metaphase, they appear merely as 0.5-1.5 μm long specks. Their small size and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrochromosome
A microchromosome (μChr) is a type of very small chromosome which is a typical component of the karyotype of birds, some reptiles, fish, and amphibians; they have yet to be found in mammals. They are less than 20 Mb in size; chromosomes which are greater than 40 Mb in size are known as macrochromosomes (MChrs), while those between 20 and 40 Mb are classified as intermediate chromosomes. Microchromosomes are characteristically very small and often cytogenetically indistinguishable in a karyotype. While originally thought to be insignificant fragments of chromosomes, in species where they have been studied they have been found to be rich in genes and high in GC content. In chickens, microchromosomes have been estimated to contain between 50 and 75% of all genes. The presence of microchromosomes makes ordering and identifying chromosomes into a coherent karyotype particularly difficult. During metaphase, they appear merely as 0.5-1.5 μm long specks. Their small size and poor co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karyotype
A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of chromosomes and any abnormalities. A karyogram or idiogram is a graphical depiction of a karyotype, wherein chromosomes are organized in pairs, ordered by size and position of centromere for chromosomes of the same size. Karyotyping generally combines light microscopy and photography, and results in a photomicrographic (or simply micrographic) karyogram. In contrast, a schematic karyogram is a designed graphic representation of a karyotype. In schematic karyograms, just one of the sister chromatids of each chromosome is generally shown for brevity, and in reality they are generally so close together that they look as one on photomicrographs as well ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precocial
In biology, altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. Precocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normally nidifugous, meaning that they leave the nest shortly after birth or hatching. These categories form a continuum, without distinct gaps between them. Altriciality Etymology The word is derived from the Latin root ''alere'', meaning "to nurse, to rear, or to nourish" and indicates the need for young to be fed and taken care of for a long duration. By contrast, species whose young are immediately or quickly mobile are called ''precocial''. Precociality Etymology The word "precocial" is derived from the same root as ''precocious'', implying early maturity in both cases. Superprecociality Extremely precocial species are called "superprecocial". Examples are the megapode birds, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mallard
The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, Colombia, the Falkland Islands, and South Africa. This duck belongs to the subfamily Anatinae of the waterfowl family Anatidae. Males have purple patches on their wings, while the females (hens or ducks) have mainly brown-speckled plumage. Both sexes have an area of white-bordered black or iridescent blue feathers called a speculum on their wings; males especially tend to have blue speculum feathers. The mallard is long, of which the body makes up around two-thirds the length. The wingspan is and the bill is long. It is often slightly heavier than most other dabbling ducks, weighing . Mallards live in wetlands, eat water plants and small animals, and are social animals preferring to congregate in groups or flocks of varyi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crest (feathers)
The crest is a prominent feature exhibited by several bird and other dinosaur species on their heads. It is distinct from features such as casques and cockscombs - sometimes erroneously referred to as "crests", which are bony and fleshy structures respectively. The crest is made up of semiplume feathers: a long rachis with barbs on either side. These are plumulaceous feathers, meaning that they are soft and bendable. In birds, these semiplumes are common along the head, neck, and upper back, and may be used for buoyancy and sensing vibrations. Crests on birds are generally used for display purposes. Cockatoos and their smaller cousins, cockatiels, are part of the parrot family Cacatuidae found in Australia, the Bismarck Archipelago and the Philippines, and are probably the most recognizable birds to feature crests. Cockatoos and cockatiels possess crests which may be raised or lowered at will. Their crests are used to communicate with fellow members of their species, or as a fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caruncle (bird Anatomy)
A caruncle is defined as 'a small, fleshy excrescence that is a normal part of an animal's anatomy'. Within this definition, caruncles in birds include wattles (or dewlaps), combs, snoods, and earlobes. The term ''caruncle'' is derived from Latin ''caruncula'', the diminutive of ''carō'', "flesh". Taxonomy Caruncles are carnosities, often of bright colors such as red, blue, yellow or white. They can be present on the head, neck, throat, cheeks or around the eyes of some birds. They may be present as combs or crests and other structures near the beak, or, hanging from the throat or neck. Caruncles may be featherless, or, have small scattered feathers. In some species, they may form pendulous structures of erectile tissue, such as the snood of the domestic turkey. Caruncles are sometimes secondary sexual characteristics, having a more intense color or even a different color, developing as the male reaches sexual maturity. Function Caruncles are also ornamental elements used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claw
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus for gripping a surface as they walk. The pincers of crabs, lobsters and scorpions, more formally known as their chelae, are sometimes called claws. A true claw is made of a hard protein called keratin. Claws are used to catch and hold prey in carnivorous mammals such as cats and dogs, but may also be used for such purposes as digging, climbing trees, self-defense and grooming, in those and other species. Similar appendages that are flat and do not come to a sharp point are called nails instead. Claw-like projections that do not form at the end of digits but spring from other parts of the foot are properly named spurs. Tetrapods In tetrapods, claws are made of keratin and consist of two layers. The unguis is the harder external layer, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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