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Bryan Clarke
Bryan Campbell Clarke (24 June 1932 – 27 February 2014) was a British Professor of genetics, latterly emeritus at the University of Nottingham. Clarke is particularly noted for his work on apostatic selection (which is a term he coined in 1962) and other forms of frequency-dependent selection, and work on polymorphism in snails, much of it done during the 1960s. Later, he studied molecular evolution. He made the case for natural selection as an important factor in the maintenance of molecular variation, and in driving evolutionary changes in molecules through time. In doing so, he questioned the over-riding importance of random genetic drift advocated by King, Jukes, and Kimura. With Professor James J Murray Jnr (University of Virginia), he carried out an extensive series of studies on speciation in land snails of the genus '' Partula'' inhabiting the volcanic islands of the Eastern Pacific. These studies helped illuminate the genetic changes that take place during the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gatley
Gatley is a suburb in the Metropolitan Borough of Stockport, Greater Manchester, England, 3 miles north-east of Manchester Airport. History Toponymy Within the boundaries of the Historic counties of England, historic county of Cheshire, in 1290, Gatley was known as ''Gateclyve'', which in Middle English means "a place where goats are kept". Early history Until the 20th century, most Gatley residents either worked in the material trades or were farmers. An open field system existed around Gatley in the late 17th century, but the practice of common farming seems to have fallen into disuse when William Tatton allowed tenants to buy their own land.Arrowsmith, Peter ''Stockport, A History'', published 1997, Gatley Carrs was the lower, marshy ground running down to the River Mersey and west to Northenden. Before 1700 it was a place for osier beds which local people had used for basket making or for wattles for cottages or fencing. In 1800, Mr Worthington of Sharston Hall planted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apostatic Selection
Apostatic selection is a form of negative frequency-dependent selection. It describes the survival of individual prey animals that are different (through mutation) from their species in a way that makes it more likely for them to be ignored by their predators. It operates on polymorphic species, species which have different forms. In apostatic selection, the common forms of a species are preyed on more than the rarer forms, giving the rare forms a selective advantage in the population. It has also been discussed that apostatic selection acts to stabilize prey polymorphisms. The term "apostatic selection" was introduced in 1962 by Bryan Clarke in reference to predation on polymorphic grove snails and since then it has been used as a synonym for negative frequency-dependent selection. The behavioural basis of apostatic selection was initially neglected, but was eventually established by A.B Bond. Apostatic selection can also apply to the predator if the predator has various mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Genetics
Population genetics is a subfield of genetics that deals with genetic differences within and among populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as Adaptation (biology), adaptation, speciation, and population stratification, population structure. Population genetics was a vital ingredient in the emergence of the Modern synthesis (20th century), 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 evolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reader (academic Rank)
The title of reader in the United Kingdom and some universities in the Commonwealth of Nations, for example India, Australia and New Zealand, denotes an appointment for a senior academic with a distinguished international reputation in research or scholarship. In the traditional hierarchy of British and other Commonwealth universities, reader (and principal lecturer in the new universities) are academic ranks above senior lecturer and below Chaired Professor, recognising a distinguished record of original research. Reader is a professor without a chair, similar to the distinction between professor and chaired professor in Hong Kong and between ''professor extraordinarius and'' ''professor ordinarius'' at some European universities. Readership is one/two rank(s) more prestigious than senior/permanent Lecturership, which translate to Associate/Assistant Professorship. Readers in the UK would correspond to the start of full professors in China and the United States.Graham WebbMak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lecturer
Lecturer is an academic rank within many universities, though the meaning of the term varies somewhat from country to country. It generally denotes an academic expert who is hired to teach on a full- or part-time basis. They may also conduct research. Comparison The table presents a broad overview of the traditional main systems, but there are universities which use a combination of those systems or other titles. Note that some universities in Commonwealth countries have adopted the American system in place of the Commonwealth system. Uses around the world Australia In Australia, the term lecturer may be used informally to refer to anyone who conducts lectures at a university or elsewhere, but formally refers to a specific academic rank. The academic ranks in Australia are similar to those in the UK, with the rank of associate professor roughly equivalent to reader in UK universities. The academic levels in Australia are (in ascending academic level): (A) associate lecture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cepaea
''Cepaea'' is a genus of large air-breathing land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs in the family Helicidae. The shells are often brightly coloured and patterned with brown stripes. The two living species in this genus, ''C. nemoralis'' and ''C. hortensis'', are widespread and common in Western and Central Europe. In North America, ''C. hortensis'' is Native species, native on the northeast coast, but both species have been introduced elsewhere, and they are also spreading further east in Europe. Both have been influential model organisms, model species for ongoing studies of genetics and natural selection. Like many Helicidae, these snails use love darts during mating. Species For a long time, four living species were classified in the genus ''Cepaea''. However, Molecular phylogenetics, molecular phylogenetic studies suggested that two of them should be placed in the genera ''Macularia'' and ''Caucasotachea'', which are not immediate relativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymorphism (biology)
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative '' phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Ford E.B. 1965. ''Genetic polymorphism''. Faber & Faber, London. Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if the jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doctor Of Philosophy
A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of Postgraduate education, graduate study and original research. The name of the degree is most often abbreviated PhD (or, at times, as Ph.D. in North American English, North America), pronounced as three separate letters ( ). The University of Oxford uses the alternative abbreviation "DPhil". PhDs are awarded for programs across the whole breadth of academic fields. Since it is an earned research degree, those studying for a PhD are required to produce original research that expands the boundaries of knowledge, normally in the form of a Thesis, dissertation, and, in some cases, defend their work before a panel of other experts in the field. In many fields, the completion of a PhD is typically required for employment as a university professor, researcher, or scientist. Definition In the context o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bachelor Of Arts
A Bachelor of Arts (abbreviated B.A., BA, A.B. or AB; from the Latin ', ', or ') is the holder of a bachelor's degree awarded for an undergraduate program in the liberal arts, or, in some cases, other disciplines. A Bachelor of Arts degree course is generally completed in three or four years, depending on the country and institution. * Degree attainment typically takes five or more years in Argentina, Brazil, Chile, and Peru. * Degree attainment typically takes four years in Afghanistan, Armenia, Azerbaijan, Bangladesh, Brunei, Bulgaria, Canada (except Quebec), China, Egypt, Finland, Georgia, Ghana, Greece, Hong Kong, Indonesia, India, Iran, Iraq, Ireland, Jamaica, Japan, Kazakhstan, Kenya, Kuwait, Latvia, Lebanon, Lithuania, Malaysia, Mexico, Mongolia, Myanmar, Nepal, the Netherlands, Nigeria, Pakistan, the Philippines, Qatar, Russia, Saudi Arabia, Scotland, Serbia, Singapore, South Africa, South Korea, Spain, Sri Lanka, Taiwan, Thailand, Turkey, Ukraine, the United S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magdalen College, Oxford
Magdalen College ( ) is a Colleges of the University of Oxford, constituent college of the University of Oxford. It was founded in 1458 by Bishop of Winchester William of Waynflete. It is one of the wealthiest Oxford colleges, as of 2022, and one of the strongest academically, setting the record for the highest Norrington Table, Norrington Score in 2010 and topping the table twice since then. It is home to several of the university's distinguished Chair (academic), chairs, including the Serena Professor of Italian#Serena Professors at Oxford, Agnelli-Serena Professorship, the Sherardian Professor of Botany, Sherardian Professorship, and the four Waynflete Professorships. The large, square Magdalen Tower is an Oxford landmark, and it is a tradition, dating to the days of Henry VII of England, Henry VII, that the college choir sings from the top of it at 6 a.m. on May Morning. The college stands next to the River Cherwell and the University of Oxford Botanic Garden. Within i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Partula (gastropod)
''Partula'' is a genus of air-breathing tropical land snails, terrestrial pulmonate gastropod mollusks in the family Partulidae.Myers, P.; Espinosa, R.; Parr, C. S.; Jones, T.; Hammond, G. S. & Dewey, T. A. (2006). The Animal Diversity Web (online). Accessed at http://animaldiversity.org. Many species of ''Partula'' are known under the general common names " Polynesian tree snail" and " Moorean viviparous tree snail". Partulids are distributed across of Pacific Ocean islands, from the Society Islands to New Guinea. Once used as decorative items in Polynesian ceremonial wear and jewelry, these small snails (averaging about one-half to three-quarters of an inch in length) gained the attention of science when Dr. Henry Crampton (along with Yoshio Kondo) spent 50 years studying and cataloging partulids, detailing their remarkable array of morphological elements, ecological niches, and behavioral aspects that illustrate adaptive radiation. Decline The partulids of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Drift
Genetic drift, also known as random genetic drift, allelic drift or the Wright effect, is the change in the Allele frequency, frequency of an existing gene variant (allele) in a population due to random chance. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. It can also cause initially rare alleles to become much more frequent and even fixed. When few copies of an allele exist, the effect of genetic drift is more notable, and when many copies exist, the effect is less notable (due to the law of large numbers). In the middle of the 20th century, vigorous debates occurred over the relative importance of natural selection versus neutral processes, including genetic drift. Ronald Fisher, who explained natural selection using Mendelian inheritance, Mendelian genetics, held the view that genetic drift plays at most a minor role in evolution, and this remained the dominant view for several decades. In 1968, population geneticist Mot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
