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Dactyly
In biology, dactyly is the arrangement of digits (fingers and toes) on the hands, feet, or sometimes wings of a tetrapod animal. The term is derived from the Greek word () meaning "finger." Sometimes the suffix "-dactylia" is used. The derived adjectives end with "-dactyl" or "-dactylous." As a normal feature Pentadactyly Pentadactyly (from Greek "five") is the condition of having five digits on each limb. It is traditionally believed that all living tetrapods are descended from an ancestor with a pentadactyl limb, although many species have now lost or transformed some or all of their digits by the process of evolution. However, this viewpoint was challenged by Stephen Jay Gould in his 1991 essay "Eight (or Fewer) Little Piggies," where he pointed out polydactyly in early tetrapods and described the specializations of digit reduction. Despite the individual variations listed below, the relationship is to the original five-digit model. In reptiles, the limbs are pentad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheme Human Hand Bones-en
Scheme or schemer may refer to: Arts and entertainment * '' The Scheme'', a BBC Scotland documentary TV series * The Scheme (band), an English pop band * ''The Scheme'', an action role-playing video game for the PC-8801, made by Quest Corporation * Schemer (comics), Richard Fisk, a Marvel Comics villain turned antihero * Horace Schemer, a fictional character in the TV series '' Shining Time Station'' * ''Schemers'' (film), a Scottish film Computing * Scheme (programming language), a minimalist dialect of Lisp * Scheme (URI), the front part of a web link, like "http" or "ftp" * Google Schemer, a former service allowing its users to share plans and interests Other uses * Classification scheme (information science), eg a thesaurus, a taxonomy, a data model or an ontology * Scheme (mathematics), a concept in algebraic geometry * Scheme (rhetoric), a figure of speech that changes a sentence's structure * Scam, an attempt to swindle or cheat people through deception * Scheme, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutionary history, evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, Evolution of birds, having evolved from earlier Theropoda, theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomy (biology), taxonomic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equidae
Equidae (commonly known as the horse family) is the Taxonomy (biology), taxonomic Family (biology), family of Wild horse, horses and related animals, including Asinus, asses, zebra, zebras, and many extinct species known only from fossils. The family evolved more than 50 million years ago, in the Eocene epoch, from a small, multi-toed ungulate into larger, single-toed animals. All Extant taxon, extant species are in the genus ''Equus (genus), Equus'', which originated in North America. Equidae belongs to the order Perissodactyla, which includes the extant tapirs and rhinoceros, and several extinct families. It is more specifically grouped within the superfamily (taxonomy), superfamily Equoidea, the only other family being the extinct Palaeotheriidae. The term equid refers to any member of this family, including any equinae, equine. Evolution The oldest known fossils assigned to Equidae were found in North America, and date from the early Eocene epoch, 54 million years ago. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, '' Eohippus'', into the large, single-toed animal of today. Humans began domesticating horses around 4000 BCE in Central Asia, and their domestication is believed to have been widespread by 3000 BCE. Horses in the subspecies ''caballus'' are domesticated, although some domesticated populations live in the wild as feral horses. These feral populations are not true wild horses, which are horses that have never been domesticated. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behavior. Horses are adapted to run, allowing them to quickly escape predator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostriches
Ostriches are large flightless birds. Two living species are recognised, the common ostrich, native to large parts of sub-Saharan Africa, and the Somali ostrich, native to the Horn of Africa. They are the heaviest and largest living birds, with adult common ostriches weighing anywhere between 63.5 and 145 kilograms and laying the largest eggs of any living land animal.Del Hoyo, Josep, et al. Handbook of the birds of the world. Vol. 1. No. 8. Barcelona: Lynx edicions, 1992. With the ability to run at 70 km/h (43.5 mph), they are the fastest birds on land. They are farmed worldwide, with significant industries in the Philippines and in Namibia. South Africa produces about 70% of global ostrich products, with the industry largely centered around the town of Oudtshoorn. Ostrich leather is a lucrative commodity, and the large feathers are used as plumes for the decoration of ceremonial headgear. Ostrich eggs and meat have been used by humans for millennia. Ostrich ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artiodactyla
Artiodactyls are placental mammals belonging to the order (biology), order Artiodactyla ( , ). Typically, they are ungulates which bear weight equally on two (an even number) of their five toes (the third and fourth, often in the form of a hoof). The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, most perissodactyls bear weight on an odd number of the five toes. Another difference between the two orders is that many artiodactyls (except for Suina) digest plant cellulose in one or more stomach chambers rather than in their intestine (as perissodactyls do). Molecular biology, along with new fossil discoveries, has found that cetaceans (whales, dolphins, and porpoises) fall within this taxonomic branch, being most closely related to Hippopotamidae, hippopotamuses. Some modern taxonomists thus apply the name Cetartiodactyla () to this group, while others opt to include cetaceans within the existing name of Artiodactyla. Some researchers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-toed Sloth
''Choloepus'' is a genus of xenarthran mammals from Central and South America within the monotypic family Choloepodidae, consisting of two-toed sloths, sometimes also called two-fingered sloths. The two species of ''Choloepus'' (which means "lame foot" in Ancient Greek), Linnaeus's two-toed sloth (''Choloepus didactylus'') and Hoffmann's two-toed sloth (''Choloepus hoffmanni''), were formerly believed on the basis of morphological studies to be the only surviving members of the sloth family Megalonychidae, but have now been shown by molecular results to be closest to extinct ground sloths of the family Mylodontidae. Extant species Evolution A study of retrovirus and mitochondrial DNA suggests that ''C. didactylus'' and ''C. hoffmani'' diverged 6 to 7 million years ago. Furthermore, based on cytochrome c oxidase subunit I sequences, a similar divergence date ( years ago) between the two populations of ''C. hofmanni'' separated by the Andes has been reported. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertragulidae
Hypertragulidae is an extinct family (biology), family of Paleogene ruminants endemic to North America from the Eocene until the Oligocene. The Hypertragulidae are Basal (phylogenetics), basal ruminants that resembled small deer or musk deer in life. However, neither deer, nor musk deer are considered to be closely related to the hypertragulids. Instead, the chevrotains are probably the closest living relatives to these ancient deer-like animals. Taxonomy Hypertragulidae was named by Edward Drinker Cope and considered paraphyletic by W. D. Matthew. It was assigned to Ruminantia by Matthew and William King Gregory; to Pecora by H.J. Cook; and to Traguloidea by Carroll.H. J. Cook. 1934. New artiodactyls from the Oligocene and Lower Miocene of Nebraska. American Midland Naturalist 15(2):148-165 Morphology Hypertragulidae have tetradactyl front feet and didactyl rear feet, which is specific to this family and no other ruminants. They ranged in body mass from as small as with ''Par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quail
Quail is a collective name for several genera of mid-sized birds generally placed in the order Galliformes. The collective noun for a group of quail is a flock, covey, or bevy. Old World quail are placed in the family Phasianidae, and New World quail are placed in the family Odontophoridae. The species of buttonquail are named for their superficial resemblance to quail, and form the family Turnicidae in the order Charadriiformes. The king quail, an Old World quail, often is sold in the pet trade, and within this trade is commonly, though mistakenly, referred to as a "button quail". Many of the common larger species are farm-raised for table food or egg consumption, and are hunted on game farms or in the wild, where they may be released to supplement the wild population, or extend into areas outside their natural range. In 2007, 40 million quail were produced in the United States. New World *Genus '' Callipepla'' ** Scaled quail, (commonly called blue quail) ''Callip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bustards
Bustards, including floricans and korhaans, are large, terrestrial birds living mainly in dry grassland areas and in steppe regions. They range in length from . They make up the family Otididae (, formerly known as Otidae). Bustards are omnivorous and opportunistic, eating leaves, buds, seeds, fruit, small vertebrates, and invertebrates.del Hoyo, J. Elliott, A. & Sargatal, J. (editors). (1996) ''Handbook of the Birds of the World. Volume 3: Hoatzin to Auks''. Lynx Edicions. There are 26 species currently recognised. Etymology The word ''bustard'' comes from the Old French ''bistarda'' and some other languages: ''abetarda'' ( pt), ''abetarda'' ( gl), ''avutarda'' ( es) used for the great bustard. The naturalist William Turner listed the English spelling "bustard" and "bistard" in 1544. All of the common names above are derived from Latin ''avis tarda'' or ''aves tardas'' given by Pliny the Elder, these names were mentioned by the Pierre Belon in 1555 and Ulisse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perissodactyla
Perissodactyla (, ), or odd-toed ungulates, is an order of ungulates. The order includes about 17 living species divided into three families: Equidae (horses, asses, and zebras), Rhinocerotidae (rhinoceroses), and Tapiridae (tapirs). They typically have reduced the weight-bearing toes to three or one of the five original toes, though tapirs retain four toes on their front feet. The nonweight-bearing toes are either present, absent, vestigial, or positioned posteriorly. By contrast, artiodactyls (even-toed ungulates) bear most of their weight equally on four or two (an even number) of the five toes: their third and fourth toes. Another difference between the two is that perissodactyls digest plant cellulose in their intestines, rather than in one or more stomach chambers as artiodactyls, with the exception of Suina, do. The order was considerably more diverse in the past, with notable extinct groups including the brontotheres, palaeotheres, chalicotheres, and the paracer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparion
''Hipparion'' is an extinct genus of three-toed, medium-sized equine belonging to the extinct tribe Hipparionini, which lived about 10-5 million years ago. While the genus formerly included most hipparionines, the genus is now more narrowly defined as hipparionines from North Africa spanning the Late Miocene. ''Hipparion'' was a mixed-feeder who ate mostly grass, and lived in the savannah biome. ''Hipparion'' evolved from '' Cormohipparion'', and went extinct due to environmental changes like cooling climates and decreasing atmospheric carbon dioxide levels. Taxonomy "Hipparion" in sensu lato The genus "Hipparion" was used for over a century as a form classification to describe over a hundred species of Holartic hipparionines from the Pliocene and Miocene eras that had three toes and isolated protocones''.'' Since then, groups such as the genera '' Cormohipparion'' ''and Neohipparion'' were proposed to further sort these species, typically based on differences in skull mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
