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Clarence Erwin McClung
Clarence Erwin McClung (April 5, 1870 – January 17, 1946) was an eminent American zoologist and prairie pioneer cytologist who discovered the role of chromosomes in sex-determination. Graduating pharmacy at the University of Kansas in 1892, after a year of teaching he entered the college as a graduate student (A.B.,1896, A.M.,1898, and Ph.D.,1902.) He studied one summer with W.M. Wheeler at the University of Chicago and at his suggestion, studied the spermatogenesis of Ziphidium fasciatum, a long-horned grasshopper; launching his scientific career in the research of chromosomes. McClung took advantage of the great abundance of grasshoppers in Kansas ''"to make them pivotal for cytological study and to found a school of grasshopper cytologists''." Later, the use of Brachystola magna ("Lubber" grasshopper) for cytological studies would spread to laboratories throughout the world, as germ-cells in the testes were very large and easily studied. Development of the “McClung Model ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoology
Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. The term is derived from Ancient Greek , ('animal'), and , ('knowledge', 'study'). Although humans have always been interested in the natural history of the animals they saw around them, and made use of this knowledge to domesticate certain species, the formal study of zoology can be said to have originated with Aristotle. He viewed animals as living organisms, studied their structure and development, and considered their adaptations to their surroundings and the function of their parts. The Greek physician Galen studied human anatomy and was one of the greatest surgeons of the ancient world, but after the fall of the Western Roman Empire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward H
Edward is an English given name. It is derived from the Anglo-Saxon name ''Ēadweard'', composed of the elements '' ēad'' "wealth, fortune; prosperous" and '' weard'' "guardian, protector”. History The name Edward was very popular in Anglo-Saxon England, but the rule of the Norman and Plantagenet dynasties had effectively ended its use amongst the upper classes. The popularity of the name was revived when Henry III named his firstborn son, the future Edward I, as part of his efforts to promote a cult around Edward the Confessor, for whom Henry had a deep admiration. Variant forms The name has been adopted in the Iberian peninsula since the 15th century, due to Edward, King of Portugal, whose mother was English. The Spanish/Portuguese forms of the name are Eduardo and Duarte. Other variant forms include French Édouard, Italian Edoardo and Odoardo, German, Dutch, Czech and Romanian Eduard and Scandinavian Edvard. Short forms include Ed, Eddy, Eddie, Ted, Teddy and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Rees Brebner Robertson
William Rees Brebner Robertson (31 May 1881 - 15 March 1941) was an American zoologist and early cytogeneticist who discovered the chromosomal rearrangement named in his honour, Robertsonian translocation, the most common structural chromosomal abnormalities seen in humans that result in syndromes of multiple malformations, including trisomy 13 Patau syndrome and trisomy 21 Down syndrome. Born in Manchester, Kansas, he was raised on a farm in Dickinson County in a small family of Scottish ancestry. Fluent in Scottish Gaelic, French and German, as a young boy he developed a keen and enduring interest in grasshoppers that proliferated in his father's fields; seven species of which formed the basis of his 1916 paper in which he described what is known as a Robertsonian translocation (ROB). Graduating Abilene High School he attended the University of Kansas (A.B., 1906; A.M., 1907), one of Clarence Erwin McClung's eager students of cytology. An Austin Teaching Fellow of Zoology at Ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoologist
Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. The term is derived from Ancient Greek , ('animal'), and , ('knowledge', 'study'). Although humans have always been interested in the natural history of the animals they saw around them, and made use of this knowledge to domesticate certain species, the formal study of zoology can be said to have originated with Aristotle. He viewed animals as living organisms, studied their structure and development, and considered their adaptations to their surroundings and the function of their parts. The Greek physician Galen studied human anatomy and was one of the greatest surgeons of the ancient world, but after the fall of the Western Roman Empire an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytologist
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. Cell biology is the study of structural and functional units of cells. Cell biology encompasses both prokaryotic and eukaryotic cells and has many subtopics which may include the study of cell metabolism, cell communication, cell cycle, biochemistry, and cell composition. The study of cells is performed using several microscopy techniques, cell culture, and cell fractionation. These have allowed for and are currently being used for discoveries and research pertaining to how cells function, ultimately giving insight into understanding larger organisms. Knowing the components of cells and how cells work is fundamental to all biological sciences while also being essential for research in biomedical fields such as ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
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] |
Sex-determination System
A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most organisms that create their offspring using sexual reproduction have two sexes. In some species there are hermaphrodites. There are also some species that are only one sex due to parthenogenesis, the act of a female reproducing without fertilization. In some species, sex determination is genetic: males and females have different alleles or even different genes that specify their sexual morphology. In animals this is often accompanied by chromosomal differences, generally through combinations of XY, ZW, XO, ZO chromosomes, or haplodiploidy. The sexual differentiation is generally triggered by a main gene (a "sex locus"), with a multitude of other genes following in a domino effect. In other cases, sex of a fetus is determined by environmental variables (such as temperature). The details of some sex-determination systems are not yet fully under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvania Academy Of Science
The Pennsylvania Academy of Science was founded and organized on April 18, 1924, and is an independent non-profit organization that strives "to embrace all disciplines of science and help ensure the scholarly and ethical pursuit of all scientific endeavors." Today the Pennsylvania Academy of Science has members throughout the United States and in other countries. The current president is Andre Walther of Cedar Crest College and the President-Elect is Tammy Tintjer of King's College. Matthew Wallace of East Stroudsburg University of Pennsylvania serves as Immediate-Past President. History During the American Association of Academies of Science meeting in December 1923, a group led by E.M. Gress, C.R. Orton, and W.A. McCubbin was formed to determine interest in starting an Academy of Science in Pennsylvania. The efforts that included 2,000 questionnaires culminated in a meeting held on April 18, 1924, in Harrisburg, Pennsylvania, and led by Frank D. Kern and S.H. Derickson. Off ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1870 Births
Year 187 ( CLXXXVII) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Quintius and Aelianus (or, less frequently, year 940 '' Ab urbe condita''). The denomination 187 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Septimius Severus marries Julia Domna (age 17), a Syrian princess, at Lugdunum (modern-day Lyon). She is the youngest daughter of high-priest Julius Bassianus – a descendant of the Royal House of Emesa. Her elder sister is Julia Maesa. * Clodius Albinus defeats the Chatti, a highly organized German tribe that controlled the area that includes the Black Forest. By topic Religion * Olympianus succeeds Pertinax as bishop of Byzantium (until 198). Births * Cao Pi, Chinese emperor of the Cao Wei state (d. 22 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1946 Deaths
Events January * January 6 - The first general election ever in Vietnam is held. * January 7 – The Allies recognize the Austrian republic with its 1937 borders, and divide the country into four occupation zones. * January 10 ** The first meeting of the United Nations is held, at Methodist Central Hall Westminster in London. ** ''Project Diana'' bounces radar waves off the Moon, measuring the exact distance between the Earth and the Moon, and proves that communication is possible between Earth and outer space, effectively opening the Space Age. * January 11 - Enver Hoxha declares the People's Republic of Albania, with himself as prime minister. * January 16 – Charles de Gaulle resigns as head of the French provisional government. * January 17 - The United Nations Security Council holds its first session, at Church House, Westminster in London. * January 19 ** The Bell XS-1 is test flown for the first time (unpowered), with Bell's chief test pilot Jack W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Episcopalians
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 * B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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