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Cambrian Chordate
The Cambrian chordates are an extinct group of animals belonging to the phylum Chordata that lived during the Cambrian, between 485 and 538 million years ago. The first Cambrian chordate known is '' Pikaia gracilens'', a lancelet-like animal from the Burgess Shale in British Columbia, Canada. The discoverer, Charles Doolittle Walcott, described it as a kind of worm (annelid) in 1911, but was later realised to be a chordate. Since the discovery of other Cambrian fossils from the Burgess Shale in 1991, and from the Chengjiang biota of China in 1991, which were later found to be of chordates, several Cambrian chordates are known, with some fossils considered as putative chordates. The Cambrian chordates are characterised by the presence of segmented muscle blocks called myomeres and notochord, the two defining features of chordates. Before the full understanding of Cambrian fossils, chordates as members the most advanced phylum were believed to appear on Earth much later than the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chordata
A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five synapomorphies include a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, and a post-anal tail. The name “chordate” comes from the first of these synapomorphies, the notochord, which plays a significant role in chordate structure and movement. Chordates are also bilaterally symmetric, have a coelom, possess a circulatory system, and exhibit metameric segmentation. In addition to the morphological characteristics used to define chordates, analysis of genome sequences has identified two conserved signature indels (CSIs) in their proteins: cyclophilin-like protein and mitochondrial inner membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cephalochordates. These CS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapodia
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed lateral outgrowths that bear the chaetae. In several groups of sea snails and sea slugs, 'parapodium' refers to lateral fleshy protrusions. __TOC__ Annelid parapodia Most species of polychaete annelids have paired, fleshy parapodia which are segmentally arranged along the body axis. Parapodia vary greatly in size and form, reflecting a variety of functions, such as gas exchange, anchorage, protection and locomotion. General description Parapodia in polychaetes can be uniramous (consisting of one lobe or ramus) but are usually biramous (two lobes or rami). In the latter case, the dorsal lobes are called notopodia and the ventral lobes neuropodia. Both neuropodia and notopodia may possess a bundle of chaetae (neurochaetae and notochaet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swedish Museum Of Natural History
The Swedish Museum of Natural History ( sv, Naturhistoriska riksmuseet, literally, the National Museum of Natural History), in Stockholm, is one of two major museums of natural history in Sweden, the other one being located in Gothenburg. The museum was founded in 1819 by the Royal Swedish Academy of Sciences, but goes back to the collections acquired mostly through donations by the academy since its foundation in 1739. These collections had first been made available to the public in 1786. The museum was separated from the Academy in 1965. One of the keepers of the collections of the academy during its earlier history was Anders Sparrman, a student of Carl Linnaeus and participant in the voyages of Captain James Cook. Another important name in the history of the museum is the zoologist, paleontologist and archaeologist Sven Nilsson, who brought the previously disorganised zoological collections of the museum into order during his time as keeper (1828–1831) before returnin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Academy Of Sciences
The Chinese Academy of Sciences (CAS); ), known by Academia Sinica in English until the 1980s, is the national academy of the People's Republic of China for natural sciences. It has historical origins in the Academia Sinica during the Republican era and was formerly also known by that name. Collectively known as the "Two Academies (两院)" along with the Chinese Academy of Engineering, it functions as the national scientific think tank and academic governing body, providing advisory and appraisal services on issues stemming from the national economy, social development, and science and technology progress. It is headquartered in Xicheng District, Beijing, with branch institutes all over mainland China. It has also created hundreds of commercial enterprises, Lenovo being one of the most famous. CAS is the world's largest research organization. It had 60,000 researchers in 2018 and 114 institutes in 2016, and has been consistently ranked among the top research organizations ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaspriggina
''Metaspriggina'' is a genus of chordate initially known from two specimens in the Middle Cambrian Burgess Shale and 44 specimens found in 2012 at the Marble Canyon bed in Kootenay National Park. Whilst named after the Ediacaran organism ''Spriggina'', later work has shown the two to be unrelated. ''Metaspriggina'' is considered to represent a primitive chordate, possibly transitional between cephalochordates and the earliest vertebrates, albeit this has been questioned because it seems to possess most of the characteristics attributed to craniates. It lacked fins and it had a weakly developed cranium, but it did possess two well-developed upward-facing eyes with nostrils behind them. ''Metaspriggina'' also possessed a notochord, along with seven pairs of pharyngeal bars, possibly made of cartilage. Surprisingly they were not formed from a singular bone, but they were formed of multiple separate pairs of bones, along with first two of them that were enlarged compared to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Camerino
The University of Camerino ( it, Università degli Studi di Camerino) is a university located in Camerino, Italy. It is the best university of Italy among those with fewer than 10,000 students, according to the Guida Censis Repubblica 2011 and 2012 ranking. It claims to have been founded in 1337 and was officially recognized by the Pope in 1723. It is organized into five faculties. History Writer and jurist Cino from Pistoia, living in Marche in the years 1319–22, and in Camerino in the spring of 1331, described the territory as teeming with law schools. Camerino became a center of learning by year 1205, offering degrees in civil law, canonical law, medicine, and literary studies. Upon the request of Gentile III da Varano, Gregory XI issued the papal edict of 29 January 1367, addressed to the municipality and to the people, authorizing Camerino to confer (after appropriate examination) bachelor and doctoral degrees with apostolic authority, although only in legal studies and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleontological Society
The Paleontological Society, formerly the Paleontological Society of America, is an international organisation devoted to the promotion of paleontology. The Society was founded in 1908 in Baltimore, Maryland, and was incorporated in April 1968 in the District of Columbia. The Society publishes the bi-monthly '' Journal of Paleontology'' and the quarterly ''Paleobiology'', holds an annual meeting in the autumn in conjunction with the Geological Society of America, sponsors conferences and lectures, and provides grants and scholarships. The Society has five geographic sections—Pacific Coast (founded March 1911), North-Central (founded May 1974), Northeastern (founded March 1977), Southeastern (founded November 1979), Rocky Mountain (founded October 1985), and South-Central (founded November 1988). Medals and awards The Society recognizes distinguished accomplishments through three awards, one recognized by a medal, the other two by inscribed plaques normally presented annually: * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Paleontology
The ''Journal of Paleontology'' is a peer-reviewed scientific journal covering the field of paleontology. It is published by the Paleontological Society. Indexing The ''Journal of Paleontology'' is indexed in: *BIOSIS Previews *Science Citation Index *The Zoological Record *GeoRef __NOTOC__ The GeoRef database is a bibliographic database that indexes scientific literature in the geosciences, including geology. Coverage ranges from 1666 to the present for North American literature, and 1933 to the present for the rest of th ... References Paleontology journals Publications established in 1927 Academic journals published by learned and professional societies Cambridge University Press academic journals Bimonthly journals Paleontological Society {{paleo-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Museum Of Natural History
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7.1 million visitors, it was the eighteenth most visited museum in the world and the second most visited natural history museum in the world after the Natural History Museum in London."The World's most popular museums", CNN.com, 22 June 2017. Opened in 1910, the museum on the National Mall was one of the first Smithsonian buildings constructed exclusively to hold the national collections and research facilities. The main building has an overall area of with of exhibition and public space and houses over 1,000 employees. The museum's collections contain over 145 million specimens of plants, animals, fossils, minerals, rocks, meteorites, human remains, and human cultural artifacts, the largest natural history collection in the world. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Burgess Shale And The Nature Of History
''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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific American
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it is the oldest continuously published magazine in the United States. ''Scientific American'' is owned by Springer Nature, which in turn is a subsidiary of Holtzbrinck Publishing Group. History ''Scientific American'' was founded by inventor and publisher Rufus Porter in 1845 as a four-page weekly newspaper. The first issue of the large format newspaper was released August 28, 1845. Throughout its early years, much emphasis was placed on reports of what was going on at the U.S. Patent Office. It also reported on a broad range of inventions including perpetual motion machines, an 1860 device for buoying vessels by Abraham Lincoln, and the universal joint which now can be found in nearly every automobile manufactured. Current issues includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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