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Ecotypic Variation
In population genetics 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 (biology), adaptation, ..., ecotypic variation is the type of genetic variation found in large, continuous geographic populations. Variation of this kind is homogeneous, due to factors such as gene flow. In 1954 Ernst Mayr wrote a landmark paper attacking the idea that subspecies in ecotypic populations would lead to the formation of incipient species.Mayr, E"Change of genetic environment and evolution."In Julian Huxley et al., eds., ''Evolution as a Process''. London: Allen and Unwin, pp. 157-180. According to Mayr, species formation occurs in populations which are small and isolated, that is, populations which exemplified typostrophic variation. Notes Population genetics {{genetics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Genetics
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, epi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homogeneous
Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, size, weight, height, distribution, texture, language, income, disease, temperature, radioactivity, architectural design, etc.); one that is heterogeneous is distinctly nonuniform in at least one of these qualities. Heterogeneous Mixtures, in chemistry, is where certain elements are unwillingly combined and, when given the option, will separate. Etymology and spelling The words ''homogeneous'' and ''heterogeneous'' come from Medieval Latin ''homogeneus'' and ''heterogeneus'', from Ancient Greek ὁμογενής (''homogenēs'') and ἑτερογενής (''heterogenēs''), from ὁμός (''homos'', “same”) and ἕτερος (''heteros'', “other, another, different”) respectively, followed by γένος (''genos'', “kind”); - ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Flow
In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent allele frequencies and therefore can be considered a single effective population. It has been shown that it takes only "one migrant per generation" to prevent populations from diverging due to drift. Populations can diverge due to selection even when they are exchanging alleles, if the selection pressure is strong enough. Gene flow is an important mechanism for transferring genetic diversity among populations. Migrants change the distribution of genetic diversity among populations, by modifying allele frequencies (the proportion of members carrying a particular variant of a gene). High rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity. For this reason, gene flow has been thought to con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Mayr
Ernst Walter Mayr (; 5 July 1904 – 3 February 2005) was one of the 20th century's leading evolutionary biologists. 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), morph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typostrophic Variation
In population genetics, typostrophic variation is the type of genetic variation found in peripherally isolated populations. Variation of this kind is heterogeneous, due to factors such as geographic isolation and inbreeding. In 1954, Ernst Mayr wrote a landmark paper developing the idea that subspecies in typostophic populations lead to formation of incipient species.Mayr, E"Change of genetic environment and evolution."In Julian Huxley et al., eds., ''Evolution as a Process''. London: Allen and Unwin, pp. 157-180. According to Mayr, species formation rarely occurred in populations which were exemplified by ecotypic variation In population genetics 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 .... Notes Population genetics {{Genetics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
