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Crown Group
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 crow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown N Stem Groups
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, particularly in Commonwealth countries, as an abstract name for the monarchy itself (and, by extension, the state of which said monarch is head) as distinct from the individual who inhabits it (that is, ''The Crown''). A specific type of crown (or coronet for lower ranks of peerage) is employed in heraldry under strict rules. Indeed, some monarchies never had a physical crown, just a heraldic representation, as in the constitutional kingdom of Belgium. Variations * Costume headgear imitating a monarch's crown is also called a crown hat. Such costume crowns may be worn by actors portraying a monarch, people at costume parties, or ritual "monarchs" such as the king of a Carnival krewe, or the person who found the trinket in a king cake. * The n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Auk
The great auk (''Pinguinus impennis''), also known as the penguin or garefowl, is an Extinction, extinct species of flightless bird, flightless auk, alcid that first appeared around 400,000 years ago and Bird extinction, became extinct in the mid-19th century. It was the only modern species in the genus ''Pinguinus''. It was not closely related to the Penguin, penguins of the Southern Hemisphere, which were named for their resemblance to this species. It bred on rocky, remote islands with easy access to the ocean and a plentiful food supply, a rarity in nature that provided only a few breeding sites for the great auks. During the non-breeding season, the auk foraged in the waters of the North Atlantic, ranging as far south as northern Spain and along the coastlines of Canada, Greenland, Iceland, the Faroe Islands, Norway, Ireland, and Great Britain. The bird was tall and weighed about , making it the largest alcid to survive into the modern era, and the second-largest member ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extant Taxon
Neontology is a part of biology that, in contrast to paleontology, studies and 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 Indian elephant (''Elephas maximus'') is an extant species, and the woolly mammoth (''Mammuthus primigenius'') is an extinct species. * The moose (''Alces alces'') is an extant species, and the Irish elk (''Megaloceros giganteus'') 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeontology (journal)
''Palaeontology'' is one of the two scientific journals of the Palaeontological Association (the other being '' Papers in Palaeontology''). It was established in 1957 and is published on behalf of the Association by Wiley-Blackwell. The editor-in-chief is Dr Paul Taylor (Natural History Museum, London). ''Palaeontology'' publishes articles on a range of palaeontological topics, including taphonomy, functional morphology, systematics, palaeo-environmental reconstruction and biostratigraphy. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 3.547, ranking it 3rd out of 54 journals in the category "Paleontology". References External links * Paleontology journals Academic journals establi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prefix
A prefix is an affix which is placed before the stem of a word. Particularly in the study of languages, a prefix is also called a preformative, because it alters the form of the word to which it is affixed. Prefixes, like other affixes, can be either inflectional, creating a new form of a word with the same basic meaning and same lexical category, or derivational, creating a new word with a new semantic meaning and sometimes also a different lexical category. Prefixes, like all affixes, are usually bound morphemes. English has no inflectional prefixes, using only suffixes for that purpose. Adding a prefix to the beginning of an English word changes it to a different word. For example, when the prefix ''un-'' is added to the word ''happy'', it creates the word ''unhappy''. The word ''prefix'' is itself made up of the stem ''fix'' (meaning "attach", in this case), and the prefix ''pre-'' (meaning "before"), both of which are derived from Latin roots. English language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Tree
A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In other words, it is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. In evolutionary biology, all life on Earth is theoretically part of a single phylogenetic tree, indicating common ancestry. Phylogenetics is the study of phylogenetic trees. The main challenge is to find a phylogenetic tree representing optimal evolutionary ancestry between a set of species or taxa. Computational phylogenetics (also phylogeny inference) focuses on the algorithms involved in finding optimal phylogenetic tree in the phylogenetic landscape. Phylogenetic trees may be rooted or unrooted. In a ''rooted'' p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haldanodon
''Haldanodon'' is an extinct docodont mammaliaform which lived in the Upper Jurassic (Kimmeridgian, about 145 million years ago). Its fossil remains have been found in Portugal, in the well-known fossil locality of Guimarota, which is in the Alcobaça Formation. It may have been a semi-aquatic burrowing insectivore, similar in habits to desmans and the platypus. Several specimens are known, include a partial skeleton and well-preserved skulls. Description ''Haldanodon'' was about as long as a desman, and may have had a similar ecology. The skull was low and triangular when seen from above. For many years it had the best-known skull material of any docodont, making it vital for understanding the taxonomic position of that mammaliaform group. It was the first Mesozoic mammaliaform discovered to possess Nasal concha, turbinal plates, a complex feature of mammalian Nasal cavity, nasal cavities. However, it also retained some curiously primitive traits in common with non-mammaliaform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blackwell Publishing
Wiley-Blackwell is an international scientific, technical, medical, and scholarly publishing business of John Wiley & Sons. It was formed by the merger of John Wiley & Sons Global Scientific, Technical, and Medical business with Blackwell Publishing in 2007. Wiley-Blackwell is now an imprint that publishes a diverse range of academic and professional fields, including biology, medicine, physical sciences, technology, social science, and the humanities. Blackwell Publishing history Blackwell Publishing was formed by the 2001 merger of two Oxford-based academic publishing companies, Blackwell Science, founded in 1939 as Blackwell Scientific Publishing, and Blackwell Publishers, founded in 1922 as Basil Blackwell & Mott. Blackwell Publishers, founded in 1926, had its origins in the 19th century Blackwell's family bookshop and publishing business. The merger between the two publishing companies created the world's leading learned society publisher. The group then acquired BMJ B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals
A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including cats, dogs, and seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birds
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 Order (biology), orders. More than half are passerine or "perching" birds. Birds have Bird wing, wings 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 Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of California Museum Of Paleontology
The University of California Museum of Paleontology (UCMP) is a paleontology museum located on the campus of the University of California, Berkeley. The museum is within the Valley Life Sciences Building (VLSB), designed by George W. Kelham and completed in 1930. Its collections are primarily intended for research and are, thus, not accessible to the public. A limited number of fossils from the collection is on display in the VLSB. Although located on the Berkeley campus, the museum is the primary locality for storing fossils collected statewide. The original fossils, around which the current collection has grown, were those gathered as part of the California Geological Survey from 1860 to 1867. Website UCMP was one of the first museums to have its own website in the early 1990s, due to its location within a technology-oriented university with a good Internet connection. The site has been applauded for its use of visually appealing graphics, was nominated for a Webby A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeopteryx
''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird'') is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaîos''), meaning "ancient", and (''ptéryx''), meaning "feather" or "wing". Between the late 19th century and the early 21st century, ''Archaeopteryx'' was generally accepted by palaeontologists and popular reference books as the oldest known bird (member of the group Avialae). Older potential avialans have since been identified, including ''Anchiornis'', ''Xiaotingia'', '' Aurornis'', and '' Baminornis''. ''Archaeopteryx'' lived in the Late Jurassic around 150 million years ago, in what is now southern Germany, during a time when Europe was an archipelago of islands in a shallow warm tropical sea, much closer to the equator than it is now. Similar in size to a Eurasian magpie, with the largest individuals possibly attaining the size of a raven, the largest species of ''Archaeopteryx'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
