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Hampton L. Carson (biologist)
Hampton Lawrence Carson (November 5, 1914 – December 19, 2004) was an eminent American biologist best known for his work on the chromosomes of new species of the fruit fly Drosophila and his contributions to our understanding of their evolution. Carson was born in Philadelphia, Pennsylvania and studied zoology there at the University of Pennsylvania, receiving his A.B. degree in 1936 and his Ph.D. degree in 1943. His doctoral thesis on the cytogenetics of dark-winged fungus gnats was considered "definitive" by Dobzhansky. Carson spent virtually all of his career at two universities — Washington University in St. Louis (1943–1971) and the University of Hawaii (1971–1985) — except for sabbatical leaves to Brazil and Australia. Carson studied the population genetics and polytene chromosome polymorphisms of the highly diverse lineage of Drosophila species on the Hawaiian islands and proposed that speciation of these flies in the island chain was tied to isolation caused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosomes
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, smaller islands. With an area of , Australia is the largest country by area in Oceania and the world's List of countries and dependencies by area, sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a Megadiverse countries, megadiverse country, and its size gives it a wide variety of landscapes and climates, with Deserts of Australia, deserts in the centre, tropical Forests of Australia, rainforests in the north-east, and List of mountains in Australia, mountain ranges in the south-east. The ancestors of Aboriginal Australians began arriving from south east Asia approximately Early human migrations#Nearby Oceania, 65,000 years ago, during the Last Glacial Period, last i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Geneticists
Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure. Population genetics was a vital ingredient in the emergence of the modern evolutionary synthesis. Its primary founders were Sewall Wright, J. B. S. Haldane and Ronald Fisher, who also laid the foundations for the related discipline of quantitative genetics. Traditionally a highly mathematical discipline, modern population genetics encompasses theoretical, laboratory, and field work. Population genetic models are used both for statistical inference from DNA sequence data and for proof/disproof of concept. What sets population genetics apart from newer, more phenotypic approaches to modelling evolution, such as evolutionary game theory and adaptive dynamics, is its emphasis on such genetic phenomena as dominance, epist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Geneticists
American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, people who self-identify their ancestry as "American" ** American English, the set of varieties of the English language native to the United States ** Native Americans in the United States, indigenous peoples of the United States * American, something of, from, or related to the Americas, also known as "America" ** Indigenous peoples of the Americas * American (word), for analysis and history of the meanings in various contexts Organizations * American Airlines, U.S.-based airline headquartered in Fort Worth, Texas * American Athletic Conference, an American college athletic conference * American Recordings (record label), a record label previously known as Def American * American University, in Washington, D.C. Sports teams Soccer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2004 Deaths
This is a list of deaths of notable people, organised by year. New deaths articles are added to their respective month (e.g., Deaths in ) and then linked here. 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 See also * Lists of deaths by day * Deaths by year {{DEFAULTSORT:deaths by year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1914 Births
This year saw the beginning of what became known as World War I, after Archduke Franz Ferdinand of Austria, heir to the Austrian throne was assassinated by Serbian nationalist Gavrilo Princip. It also saw the first airline to provide scheduled regular commercial passenger services with heavier-than-air aircraft, with the St. Petersburg–Tampa Airboat Line. Events January * January 1 – The St. Petersburg–Tampa Airboat Line in the United States starts services between St. Petersburg and Tampa, Florida, becoming the first airline to provide scheduled regular commercial passenger services with heavier-than-air aircraft, with Tony Jannus (the first federally-licensed pilot) conveying passengers in a Benoist XIV flying boat. Abram C. Pheil, mayor of St. Petersburg, is the first airline passenger, and over 3,000 people witness the first departure. * January 11 – The Sakurajima volcano in Japan begins to erupt, becoming effusive after a very large earthquake o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Philosophical Society
The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and community outreach. Considered the first learned society in the United States, it has about 1,000 elected members, and by April 2020 had had only 5,710 members since its creation. Through research grants, published journals, the American Philosophical Society Museum, an extensive library, and regular meetings, the society supports a variety of disciplines in the humanities and the sciences. Philosophical Hall, now a museum, is just east of Independence Hall in Independence National Historical Park; it was designated a National Historic Landmark in 1965. History The Philosophical Society, as it was originally called, was founded in 1743 by Benjamin Franklin, James Alexander, Francis Hopkinson, John Bartram, Philip Syng, Jr. and others as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leidy Award
The Leidy Award is a medal and prize presented by the Academy of Natural Sciences of Drexel University (formerly the Academy of Natural Sciences of Philadelphia), Philadelphia, Pennsylvania, USA. It was named after US palaeontologist Joseph Leidy. The award was established in 1923 to recognize excellence in "publications, explorations, discoveries or research in the natural sciences", and was intended to be presented every three years. The award consists of a rectangular bronze medal (decorated with a bust depiction of Leidy) and an honorarium which was initially $5000. Laureates *1925 – Herbert Spencer Jennings *1928 – Henry Augustus Pilsbry *1931 – William Morton Wheeler *1934 – Gerrit Smith Miller Jr. *1937 – Edwin Linton *1940 – Merritt Lyndon Fernald *1943 – Chancey Juday *1946 – Ernst Mayr *1949 – Warren Poppino Spencer *1952 – G. Evelyn Hutchinson *1955 – Herbert Friedmann *1958 – Herbert Barker Hungerford *1961 – Robert Evans Snodgrass *1964 – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speciation
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within lineages. Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book ''On the Origin of Species''. He also identified sexual selection as a likely mechanism, but found it problematic. There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, parapatric, and sympatric. Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments. Whether genetic drift is a minor or major contributor to speciation is the subject of much ongoing discussion. Rapid sympatric speciation can take place through polyploidy, such as by doubling of chromosome numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaiian Drosophila
The Hawaiian Drosophilidae are a lineage of flies within the genus ''Drosophila.'' This monophyletic clade includes all of the endemic Hawaiian ''Drosophila'' and all members of the genus '' Scaptomyza'', which contains both Hawaiian and non-Hawaiian species. The Hawaiian Drosophilidae are descended from a common ancestor estimated to have lived 25 million years ago. Species of Hawaiian Drosophilidae flies have been studied as models of speciation and behavioral evolution. Along with other members of the native Hawaiian ecosystem, the conservations status of many species of Hawaiian Drosophilidae is threatened by habitat loss and introduced predators, among other factors. Diversity There are an estimated 1,000 species of Hawaiian Drosophilidae. 689 species have been described, including 273 species in the genus '' Scaptomyza'', of which 148 are endemic to the Hawaiian archipelago, and 416 Hawaiian endemic species in the genus ''Drosophila.'' Within the Hawaiian ''Drosophila'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area and the List of countries and dependencies by population, seventh most populous. Its capital is Brasília, and List of cities in Brazil by population, its most populous city is São Paulo. The federation is composed of the union of the 26 States of Brazil, states and the Federal District (Brazil), Federal District. It is the largest country to have Portuguese language, Portuguese as an List of territorial entities where Portuguese is an official language, official language and the only one in the Americas; one of the most Multiculturalism, multicultural and ethnically diverse nations, due to over a century of mass Immigration to Brazil, immigration from around the world; and the most populous Catholic Church by country, Roman Catholic-major ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila
''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly. One species of ''Drosophila'' in particular, '' D. melanogaster'', has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological literature. The entire genus, however, contains more than 1,500 species and is very diverse in appearan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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