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Phylogenetic Taxonomy
Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which can be a specimen or a taxon of lower rank, and a description in words. Phylogenetic nomenclature is currently regulated by the '' International Code of Phylogenetic Nomenclature'' (''PhyloCode''). Definitions Phylogenetic nomenclature ties names to clades, groups consisting of an ancestor and all its descendants. These groups can equivalently be called monophyletic. There are slightly different ways of specifying the ancestor, which are discussed below. Once the ancestor is specified, the meaning of the name is fixed: the ancestor and all organisms which are its descendants are included in the named taxon. Listing all these organisms (i.e. providing a full circumscription) requires the full phylogenetic tree to be known. In practice, ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade Names And Phylogenetic Hypotheses
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apatosaurus
''Apatosaurus'' (; meaning "deceptive lizard") is a genus of herbivorous sauropod dinosaur that lived in North America during the Late Jurassic period. Othniel Charles Marsh described and named the first-known species, ''A. ajax'', in 1877, and a second species, ''A. louisae'', was discovered and named by William H. Holland in 1916. ''Apatosaurus'' lived about 152 to 151 million years ago (mya), during the late Kimmeridgian to early Tithonian age, and are now known from fossils in the Morrison Formation of modern-day Colorado, Oklahoma, New Mexico, Wyoming, and Utah in the United States. ''Apatosaurus'' had an average length of , and an average mass of . A few specimens indicate a maximum length of 11–30% greater than average and a mass of approximately . The cervical vertebrae of ''Apatosaurus'' are less elongated and more heavily constructed than those of ''Diplodocus'', a diplodocid like ''Apatosaurus'', and the bones of the leg are much stockier despite being longer, imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Clade
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, which includes the most recent common ancestor of all modern birds, and all of its extant or extinct descendants. The concept was developed by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms relative to their extinct relatives in his "Die Stammesgeschichte der Insekten", and the "crown" and "stem" group terminology was coined by R. P. S. Jefferies in 1979. Though formulated in the 1970s, the term was not commonly used until its reintroduction in 2000 by Graham Budd and Sören Jensen. Contents of the crown gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stegosaurus Armatus
''Stegosaurus'' (; ) is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been found in the western United States and in Portugal, where they are found in Kimmeridgian- to early Tithonian-aged strata, dating to between 155 and 145 million years ago. Of the species that have been classified in the upper Morrison Formation of the western US, only three are universally recognized: ''S. stenops'', ''S. ungulatus'' and ''S. sulcatus''. The remains of over 80 individual animals of this genus have been found. ''Stegosaurus'' would have lived alongside dinosaurs such as ''Apatosaurus'', ''Diplodocus'', ''Brachiosaurus'', ''Ceratosaurus'', and ''Allosaurus''; the latter two may have preyed on it. They were large, heavily built, herbivorous quadrupeds with rounded backs, short fore limbs, long hind limbs, and tails held high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cacatua Galerita
The sulphur-crested cockatoo (''Cacatua galerita'') is a relatively large white cockatoo found in wooded habitats in Australia, New Guinea, and some of the islands of Indonesia. They can be locally very numerous, leading to them sometimes being considered pests. A highly intelligent bird, they are well known in aviculture, although they can be demanding pets. Distribution In Australia, sulphur-crested cockatoos can be found widely in the north and east, ranging from the Kimberley to as far south as Tasmania, but avoiding arid inland areas with few trees. They are numerous in suburban habitats in cities such as Adelaide, Melbourne, Canberra, Sydney and Brisbane. Except for highland areas, they occur throughout most of New Guinea and on nearby smaller islands such as Waigeo, Misool and Aru, and various islands in the Cenderawasih Bay and Milne Bay. There are four recognised subspecies: Introduced species Within Australia, sulphur-crested cockatoos of the nominate race have also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neornithes
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extant Taxon
Neontology is a part of biology that, in contrast to paleontology, deals with living (or, more generally, '' recent'') organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct. For example: * The moose (''Alces alces'') is an extant species, and the dodo (''Raphus cucullatus'') is an extinct species. * In the group of molluscs known as the cephalopods, there were approximately 600 extant species and 7,500 extinct species. A taxon can be classified as extinct if it is broadly agreed or certified that no members of the group are still alive. Conversely, an extinct taxon can be reclassified as extant if there are new discoveries of living species ("Lazarus species"), or if previously-known extant species are reclassified as members of the taxon. Most biologists, zoologists, and botanists are in practice neontologists, and the term neontologist is used large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The International Code Of Phylogenetic Nomenclature
''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of pronoun ''thee'') when followed by a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snakes
Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads (cranial kinesis). To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. Lizards have evolved elongate bodies without limbs or with greatly reduced limbs about twenty-five times independently via convergent evolution, leading to many lineages of legless lizards. These resemble snakes, but several common groups of legless lizards have eyelids and external ears, which snakes lack, although this rule is not universal (see Amphisbaenia, D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct therapsids and all extant mammals). Tetrapods evolved from a clade of primitive semiaquatic animals known as the Tetrapodomorpha which, in turn, evolved from ancient lobe-finned fish (sarcopterygians) around 390 million years ago in the Middle Devonian period; their forms were transitional between lobe-finned fishes and true four-limbed tetrapods. Limbed vertebrates (tetrapods in the broad sense of the word) are first known from Middle Devonian trackways, and body fossils became common near the end of the Late Devonian but these were all aquatic. The first crown-tetrapods (last common ancestors of extant tetrapods capable of terrestrial locomotion) appeared by the very early Carboniferous, 350 million years ago. The specific aquatic ancestors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Squirrel
The red squirrel (''Sciurus vulgaris'') is a species of tree squirrel in the genus ''Sciurus'' common throughout Europe and Asia. The red squirrel is an arboreal, primarily herbivorous rodent. In Great Britain, Ireland, and in Italy numbers have decreased drastically in recent years. This decline is associated with the introduction by humans of the eastern grey squirrel (''Sciurus carolinensis'') from North America. However, the population in Scotland is stabilising due to conservation efforts, awareness and the increasing population of the pine marten, a European predator that selectively controls grey squirrels. Description The red squirrel has a typical head-and-body length of , a tail length of , and a mass of . Males and females are the same size. The red squirrel is somewhat smaller than the eastern grey squirrel which has a head-and-body length of and weighs between . The long tail helps the squirrel to balance and steer when jumping from tree to tree and running ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Cottontail Rabbit
The eastern cottontail (''Sylvilagus floridanus'') is a New World cottontail rabbit, a member of the family Leporidae. It is the most common rabbit species in North America. Distribution The eastern cottontail can be found in meadows and shrubby areas in the eastern and south-central United States, southern Canada, eastern Mexico, Central America and northernmost South America. It is also found on the Caribbean island of Margarita. It is abundant in Midwest North America. Its range expanded north as forests were cleared by settlers.Godin, Alfred J. (1977). ''Wild mammals of New England''. Baltimore, MD: The Johns Hopkins University Press Originally, it was not found in New England, but it has been introduced and now competes for habitat there with the native New England cottontail. It has also been introduced into parts of Oregon, Washington, and British Columbia. In the 1950s and 1960s, the eastern cottontail was introduced to France and northern Italy, where it displayed a rapid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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