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Cladistic Taxonomy
Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics (synapomorphies) that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms ''worms'' or ''fishes'' were used within a ''strict'' cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a ' grade', which are fruitless to precisely delineate, especially when in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek Dark Ages, Dark Ages (), the Archaic Greece, Archaic or Homeric Greek, Homeric period (), and the Classical Greece, Classical period (). Ancient Greek was the language of Homer and of fifth-century Athens, fifth-century Athenian historians, playwrights, and Ancient Greek philosophy, philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Homeric Greek, Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willi Hennig
Emil Hans Willi Hennig (20 April 1913 – 5 November 1976) was a German biologist and zoologist who is considered the founder of phylogenetic systematics, otherwise known as cladistics. In 1945 as a prisoner of war, Hennig began work on his theory of cladistics, which he published in German in 1950, with a substantially revised English translation published in 1966. With his works on evolution and systematics he revolutionised the view of the natural order of beings. As a taxonomist, he specialised in dipterans (true flies). Hennig coined the key terms synapomorphy, symplesiomorphy, and paraphyly. He also asserted, in his "auxiliary principle", that "the presence of apomorphous characters in different species 'is always reason for suspecting kinship .e., that species belong to a monophyletic group and that their origin by convergence should not be presumed a priori' (Hennig, 1953). This was based on the conviction that 'phylogenetic systematics would lose all ground on which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Sokal
Robert Reuven Sokal (January 13, 1926, in Vienna, Austria – April 9, 2012, in Stony Brook, New York) was an Austrian– American biostatistician and entomologist. Distinguished Professor Emeritus at the Stony Brook University, Sokal was a member of the National Academy of Sciences and the American Academy of Arts and Sciences. He promoted the use of statistics in biology and co-founded the field of numerical taxonomy, together with Peter H. A. Sneath. Life Sokal was born in 1926 in a Jewish family in Vienna, Austria. In 1939, following the annexation of Austria by Nazi Germany, he escaped with his family to China. He earned his bachelor's degree at St. John's College in Shanghai, where he married, and from there moved with his wife Julie to the University of Chicago, where he also worked as a librarian to complement his scholarship. He took his Ph.D. degree under the supervision of the well-known termite systematist Alfred E. Emerson. He was also strongly influenced by Sewa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Sneath
Peter Henry Andrews Sneath FRS, MD (17 November 1923 – September 9, 2011) was a British microbiologist who co-founded the field of numerical taxonomy Numerical taxonomy is a classification system in biological systematics which deals with the grouping by numerical methods of taxonomic units based on their character states. It aims to create a taxonomy using numeric algorithms like cluster an ..., together with Robert R. Sokal. Sneath and Sokal wrote ''Principles of Numerical Taxonomy'', revised in 1973 as ''Numerical Taxonomy''. Sneath reviewed the state of numerical taxonomy in 1995 and wrote some autobiographical notes in 2010. A special issue of the journal Antonie van Leeuwenhoek, on microbial systematics, is dedicated to the memory of Peter Sneath. References External linksPeter H. A. Sneath (1923 - 2011) 1923 births 2011 deaths British microbiologists Fellows of the Royal Society Place of birth missing British taxonomists {{Geneticist-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Numerical Taxonomy
Numerical taxonomy is a classification system in biological systematics which deals with the grouping by numerical methods of taxonomic units based on their character states. It aims to create a taxonomy using numeric algorithms like cluster analysis rather than using subjective evaluation of their properties. The concept was first developed by Robert R. Sokal and Peter H. A. Sneath in 1963 and later elaborated by the same authors.Sneath and Sokal: ''Numerical Taxonomy'', San Francisco: W.H. Freeman, 1974 by Tejanshu Ravesh They divided the field into phenetics in which classifications are formed based on the patterns of overall similarities and cladistics in which classifications are based on the branching patterns of the estimated evolutionary history of the taxa.{{cn span, In recent years many authors treat numerical taxonomy and phenetics as synonyms despite the distinctions made by those authors., date=May 2017 Although intended as an objective method, in practice the ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Taxonomy
Evolutionary taxonomy, evolutionary systematics or Darwinian classification is a branch of biological classification that seeks to classify organisms using a combination of phylogenetic relationship (shared descent), progenitor-descendant relationship (serial descent), and degree of evolutionary change. This type of taxonomy may consider whole taxa rather than single species, so that groups of species can be inferred as giving rise to new groups. The concept found its most well-known form in the modern evolutionary synthesis of the early 1940s. Evolutionary taxonomy differs from strict pre-Darwinian Linnaean taxonomy (producing orderly lists only) in that it builds evolutionary trees. While in phylogenetic nomenclature each taxon must consist of a single ancestral node and all its descendants, evolutionary taxonomy allows for groups to be excluded from their parent taxa (e.g. dinosaurs are not considered to ''include'' birds, but to have ''given rise'' to them), thus permitting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenetics
In biology, phenetics (; ), also known as taximetrics, is an attempt to classify organisms based on overall similarity, usually with respect to morphology or other observable traits, regardless of their phylogeny or evolutionary relation. It is related closely to numerical taxonomy which is concerned with the use of numerical methods for taxonomic classification. Many people contributed to the development of phenetics, but the most influential were Peter Sneath and Robert R. Sokal. Their books are still primary references for this sub-discipline, although now out of print. Phenetics has been largely superseded by cladistics for research into evolutionary relationships among species. However, certain phenetic methods, such as neighbor-joining, are used for phylogenetics, as a reasonable approximation of phylogeny when more advanced methods (such as Bayesian inference) are too expensive computationally. Phenetic techniques include various forms of clustering and ordination. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Mayr
Ernst Walter Mayr ( ; ; 5 July 1904 – 3 February 2005) was a German-American evolutionary biologist. He was also a renowned Taxonomy (biology), taxonomist, tropical explorer, ornithologist, Philosophy of biology, philosopher of biology, and History of science, historian of science. His work contributed to the conceptual revolution that led to the Modern synthesis (20th century), modern evolutionary synthesis of Gregor Mendel, Mendelian genetics, systematics, and Charles Darwin, Darwinian evolution, and to the development of the Species, biological species concept. Although Charles Darwin and others posited that multiple species could evolve from a single common ancestor, the mechanism by which this occurred was not understood, creating the ''species problem''. Ernst Mayr approached the problem with a new definition for species. In his book ''Systematics and the Origin of Species'' (1942) he wrote that a species is not just a group of Morphology (biology), morphologically sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur Cain
Arthur James Cain FRS (25 July 1921 – 20 August 1999) was a British evolutionary biologist and ecologist. He was elected a Fellow of the Royal Society in 1989. Career Arthur James Cain was born and grew up in Rugby in Warwickshire, England. In 1939 he was awarded a prestigious scholarship ( Demyship) to Magdalen College, Oxford, where he graduated with first class honors in Zoology in 1941. Entering the British army in December 1941, Cain was commissioned second lieutenant in the Royal Army Ordnance Corps (engineering) and was later transferred to the Royal Electrical and Mechanical Engineers (R.E.M.E.) on its formation. He was promoted to captain in 1942. After leaving the military in November 1945, Cain returned to Oxford to pursue research in the Department of Zoology. He became a Departmental Demonstrator in October 1946, finishing his D. Phil. in 1948. From January 1949 until 1964 Cain was employed as University Demonstrator in Animal Taxonomy. In addition he was ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lucien Cuénot
Lucien Claude Marie Julien Cuénot (; 21 October 1866 – 7 January 1951) was a French biologist. In the first half of the 20th century, Mendelism was not a popular subject among French biologists. Cuénot defied popular opinion and shirked the “pseudo-sciences” as he called them. Upon the rediscovery of Mendel's work by Correns, De Vries, and Tschermak, Cuénot proved that Mendelism applied to animals as well as plants. Cuénot's experiments Cuénot spent two years working on mice and came to the conclusion that three “mnemons” (genes) are responsible for the production of one “chromogen” or pigment and two “distases” enzymes. The pigment (if present) is acted upon by the enzymes to produce black or yellow colour. If no pigment is present the result is an albino mouse. Cuénot studied the offspring of various crosses between mice and concluded that these “mnemons” or genes were inherited in a Mendelian fashion. Subsequently, Cuénot was the first person to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julian Huxley
Sir Julian Sorell Huxley (22 June 1887 – 14 February 1975) was an English evolutionary biologist, eugenicist and Internationalism (politics), internationalist. He was a proponent of natural selection, and a leading figure in the mid-twentieth-century Modern synthesis (20th century), modern synthesis. He was secretary of the Zoological Society of London (1935–1942), the first director of UNESCO, a founding member of the World Wildlife Fund, the president of the British Eugenics Society (1959–1962), and the first president of the British Humanist Association. Huxley was well known for his presentation of science in books and articles, and on radio and television. He directed an Oscar-winning wildlife film. He was awarded UNESCO's Kalinga Prize for the popularisation of science in 1953, the Darwin Medal of the Royal Society in 1956, and the Darwin–Wallace Medal of the Linnaean Society in 1958. He was also British honours system, knighted in the 1958 New Year Honours, a hun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter Max Zimmerman
Walter Max Zimmermann (May 9, 1892 – June 30, 1980) was a German botanist and systematist. Zimmermann’s notions of classifying life objectively based on phylogenetic methods and on evolutionarily important characters were foundational for modern phylogenetics. Though they were later implemented by Willi Hennig in his fundamental work on phylogenetic systematics, Zimmermann's contributions to this field have largely been overlooked. Zimmermann also made several significant developments in the field of plant systematics such as the discovery of the telome theory. The standard botanical author abbreviation W.Zimm. is applied to species he described. Biography Walter Zimmermann was born in Walldürn, Germany. He began his collegiate studies in 1910 at the University of Karlsruhe and later transferred to University of Freiburg in 1911. After transferring between the institutions of Friedrich Wilhelm University and University of Monaco and serving in World War I, he returned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
