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Alula Records
The alula , or bastard wing, (plural ''alulae'') is a small projection on the anterior edge of the wing of modern birds and a few non-avian dinosaurs. The word is Latin and means "winglet"; it is the diminutive of ''ala'', meaning "wing". The alula is the freely moving first digit, a bird's "thumb", and typically bears three to five small flight feathers, with the exact number depending on the species. There also are minor covert feathers overlying the flight feathers. Like the larger flight feathers found on the wing's trailing edge, these alula feathers are asymmetrical, with the shaft running closer to anterior edge. Function In most situations, the alula is held flush against the wing; however, it can be manipulated. When flying at slow speeds or landing, the bird moves its alula slightly upwards and forward, which creates a small slot on the wing's leading edge. This functions in the same way as the slats on the leading edge of the wing of an aircraft, allowing the wing to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peregrine Falcon
The peregrine falcon (''Falco peregrinus''), also known simply as the peregrine, is a Cosmopolitan distribution, cosmopolitan bird of prey (raptor) in the family (biology), family Falconidae renowned for its speed. A large, Corvus (genus), crow-sized falcon, it has a blue-grey back, barred white underparts, and a black head. As is typical for avivore, bird-eating (avivore) raptors, peregrine falcons are Sexual dimorphism, sexually dimorphic, with females being considerably larger than males. Historically, it has also been known as "black-cheeked falcon" in Australia, and "duck hawk" in North America. The breeding range includes land regions from the Arctic tundra to the tropics. It can be found nearly everywhere on Earth, except extreme polar regions, very high mountains, and most tropical rainforests; the only major ice-free landmass from which it is entirely absent is New Zealand. This makes it the world's most widespread Raptor (bird), raptor and one of the most widely found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leading Edge Slot
A leading-edge slot is a fixed aerodynamics, aerodynamic feature of the wing of some aircraft to reduce the Stall (flight), stall speed and promote good low-speed handling qualities. A leading-edge slot is a spanwise gap in each wing, allowing air to flow from below the wing to its upper surface. In this manner they allow flight at higher angle of attack, angles of attack and thus reduce the stall speed. Purpose and development At an angle of attack above about 15° many airfoils enter the stall (flight), stall. Modification of such an airfoil with a fixed leading-edge slot can increase the stalling angle to between 22° and 25°.Clancy, L.J., ''Aerodynamics'', Section 6.9 Slots were first developed by Handley Page in 1919 and the first aircraft to fly with them was the experimental H.P.17, a modified Airco DH.9A. Their invention is credited jointly to Sir Frederick Handley Page and Gustav Lachmann. The first aircraft fitted with controllable slots was the Handley Page H.P.20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Flight
Bird flight is the primary mode of animal locomotion, locomotion used by most bird species in which birds take off and flight, fly. Flight assists birds with feeding, Sexual reproduction, breeding, avoiding predation, predators, and Bird migration, migrating. Bird flight includes multiple types of motion, including hovering, taking off, and landing, involving many complex movements. As different bird species adapted over millions of years through evolution for specific environments, prey, predators, and other needs, they developed Generalist and specialist species, specializations in their wing (bird), wings, and acquired different forms of flight. Various theories exist about how bird flight evolution, evolved, including flight from falling or gliding (the ''trees down'' hypothesis), from running or leaping (the ''ground up'' hypothesis), from ''wing-assisted incline running'' or from '' proavis'' (pouncing) behavior. Basic mechanics of bird flight Lift, drag and thrust The f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Origin Of Birds
The scientific question of which larger group of animals birds evolved within has traditionally been called the "origin of birds". The present scientific consensus is that birds are a group of maniraptoran theropod dinosaurs that originated during the Mesozoic era. A close relationship between birds and dinosaurs was first proposed in the nineteenth century after the discovery of the primitive bird '' Archaeopteryx'' in Germany. Birds and extinct non-avian dinosaurs share many unique skeletal traits. Moreover, fossils of more than thirty species of non-avian dinosaur with preserved feathers have been collected. There are even very small dinosaurs, such as ''Microraptor'' and ''Anchiornis'', which have long, vaned arm and leg feathers forming wings. The Jurassic basal avialan '' Pedopenna'' also shows these long foot feathers. Paleontologist Lawrence Witmer concluded in 2009 that this evidence is sufficient to demonstrate that avian evolution went through a four-winged stage. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolved
Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. The process of evolution has given rise to biodiversity at every level of biological organisation. The scientific theory of evolution by natural selection was conceived independently by two British naturalists, Charles Darwin and Alfred Russel Wallace, in the mid-19th century as an explanation for why organisms are adapted to their physical and biological environments. The theory was first set out in detail in Darwin's book ''On the Origin of Species''. Evolution by natural selection is established by observable facts about living organisms: (1) more offspring are often produced than can possibly survive; (2) phenotypic variatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protopteryx Fengningensis
''Protopteryx'' is an extinct bird and possibly the basalmost enantiornithean, from the Cretaceous period.Zhou, Zhonghe. (2002). "A new and primitive enantiornithine bird from the Early Cretaceous of China." ''Journal of Vertebrate Paleontology'', 22(1): 49-57. The type species is ''P. fengningensis''. It was first discovered in the Sichakou Member of the Yixian Formation or Huajiying Formation of Hebei Province, northern China, dating from 131 Ma ago.O'Connor, J.K., Zhou Z. and Zhang F. (In press). "A reappraisal of ''Boluochia zhengi'' (Aves: Enantiornithes) and a discussion of intraclade diversity in the Jehol avifauna, China." ''Journal of Systematic Palaeontology'', (published online before print 16 December 2010). ''Protopteryx ''has been found in the Daibeigou formation, as well.Zhiheng Li, Zhonghe Zhou, Min Wang, Julia A. Clarke, (2014). "A New Specimen of Large-Bodied Basal Enantiornithine ''Bohaiornis'' from the Early Cretaceous of China and the Inference of Feeding Eco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mya (unit)
Mya or MYA may refer to: Brands and product names * Mya (TV channel), an Italian Television channel * Mya (program), an intelligent personal assistant created by Motorola * Midwest Young Artists, a comprehensive youth music program Codes * Burmese language (ISO 639-3: ) * Moruya Airport (IATA code: MYA), New South Wales, Australia * The IOC, license plate, and UNDP country code for Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ... People * Mya (given name) * Mya (singer) (Mya Marie Harrison, born 1979), American R&B singer-songwriter and actress * Bo Mya (1927–2006), Myanmar rebel leader and chief commander of the Karen National Union Other uses * ''Mýa'' (album), a 1998 album by Mýa * ''Mya'' (bivalve), a genus of soft-shell clams * Million years a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geological period of the entire Phanerozoic. The name is derived from the Latin , 'chalk', which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation . The Cretaceous was a period with a relatively warm climate, resulting in high Sea level#Local and eustatic, eustatic sea levels that created numerous shallow Inland sea (geology), inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was largely ice-free, although there is some evidence of brief periods of glaciation during the cooler first half, and forests extended to the poles. Many of the dominant taxonomic gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiornithes
The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct Avialae, avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over seventy species of Enantiornithes have been named, but some names represent only single bones, so it is likely that not all are valid. The Enantiornithes became extinct at the Cretaceous–Paleogene boundary, along with Hesperornithes and all other non-avian dinosaurs. Discovery and naming The first Enantiornithes to be discovered were incorrectly referred to modern bird groups. For example, the first known species of Enantiornithes, ''Gobipteryx minuta'', was originally considered a paleognath related to ostriches and tinamou. The Enantiornithes were first recognized as a distinct lineage, or "subclass" of birds, by Cyril A. Walker in 1981. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eoalulavis Hoyasi
''Eoalulavis'' (from the Ancient Greek: Eos, ''Éōs'', "dawn"; ''alula'', alula, "bastard wing"; ''avis'', "bird") is a monotypic taxon, monotypic genus of Enantiornithines, enantiornithean bird that lived during the Barremian, in the Lower Cretaceous around 125 million years ago. The only known species is ''Eoalulavis hoyasi''. (1996)An Early Cretaceous bird from Spain and its implications for the evolution of avian flight ''Nature (journal), Nature'' 382(6590): 442-445. (HTML abstract) (2002): "The birds from the lower Cretaceous of las hoyas (Province of Cuenca, Spain)", Mesozoic Birds: Above the Heads of the Dinosaurs.University of California Press, Berkeley, pp. 209-229. Discovery Its remains came from the Lagerstätte, Konservat-Lagerstätte of Las Hoyas, Cuenca, Spain, Cuenca, Spain. The holotype (LH13500), housed in the collection of , consists on both slab and counterslab preserving mainly the thoracic region, part of the neck and both almost complete forelimbs of an ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
