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Evolutionarily Stable Strategy
An evolutionarily stable strategy (ESS) is a strategy (or set of strategies) that is ''impermeable'' when adopted by a population in adaptation to a specific environment, that is to say it cannot be displaced by an alternative strategy (or set of strategies) which may be novel or initially rare. Introduced by John Maynard Smith and George R. Price in 1972/3, it is an important concept in behavioural ecology, evolutionary psychology, mathematical game theory and economics, with applications in other fields such as anthropology, philosophy and political science. In game-theoretical terms, an ESS is an equilibrium refinement of the Nash equilibrium, being a Nash equilibrium that is also "evolutionarily stable." Thus, once fixed in a population, natural selection alone is sufficient to prevent alternative ( mutant) strategies from replacing it (although this does not preclude the possibility that a better strategy, or set of strategies, will emerge in response to selective press ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Nash Equilibrium
In game theory, the Nash equilibrium is the most commonly used solution concept for non-cooperative games. A Nash equilibrium is a situation where no player could gain by changing their own strategy (holding all other players' strategies fixed). The idea of Nash equilibrium dates back to the time of Cournot, who in 1838 applied it to his model of competition in an oligopoly. If each player has chosen a strategy an action plan based on what has happened so far in the game and no one can increase one's own expected payoff by changing one's strategy while the other players keep theirs unchanged, then the current set of strategy choices constitutes a Nash equilibrium. If two players Alice and Bob choose strategies A and B, (A, B) is a Nash equilibrium if Alice has no other strategy available that does better than A at maximizing her payoff in response to Bob choosing B, and Bob has no other strategy available that does better than B at maximizing his payoff in response to Alice c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Anthropology
Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, society, societies, and linguistics, in both the present and past, including archaic humans. Social anthropology studies patterns of behaviour, while cultural anthropology studies cultural meaning, including norms and values. The term sociocultural anthropology is commonly used today. Linguistic anthropology studies how language influences social life. Biological anthropology, Biological (or physical) anthropology studies the biology and evolution of Human evolution, humans and their close primate relatives. Archaeology, often referred to as the "anthropology of the past," explores human activity by examining physical remains. In North America and Asia, it is generally regarded as a branch of anthropology, whereas in Europe, it is considered either an independent discipline or classified under related fields like history and palaeontology. Etymology The abstract noun ''wikt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Fisher's Principle
Fisher's principle is an evolutionary model that explains why the sex ratio of most species that produce offspring through sexual reproduction is approximately 1:1 between males and females. A. W. F. Edwards has remarked that it is "probably the most celebrated argument in evolutionary biology". Fisher's principle was outlined by Ronald Fisher in his 1930 book ''The Genetical Theory of Natural Selection'' (but has been incorrectly attributed as original to Fisher). Fisher couched his argument in terms of parental expenditure, and predicted that parental expenditure on both sexes should be equal. Sex ratios that are 1:1 are hence known as "", and those that are ''not'' 1:1 are "" or "" and occur because they break the assumptions made in Fisher's model. Basic explanation W. D. Hamilton gave the following simple explanation in his 1967 paper on "Extraordinary sex ratios", given the condition that males and females cost equal amounts to produce: # Suppose male births are less commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Sex Ratio
A sex ratio is the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. However, many species deviate from an even sex ratio, either periodically or permanently. These include parthenogenic and androgenetic species, periodically mating organisms such as aphids, some eusocial wasps, bees, ants, and termites. Types In most species, the sex ratio varies according to the age profile of the population. It is generally divided into four subdivisions: * — ratio at fertilization * — ratio at birth * — ratio in sexually mature organisms ** The tertiary sex ratio is equivalent to the (ASR), which is defined as the ratio of adult males to females in a population. ** The operational sex ratio (OSR) is the ratio of ''sexually active'' males to females in a population, and is therefore derived from a subset of the individuals included when calculating the ASR. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Robert MacArthur
Robert Helmer MacArthur (April 7, 1930 – November 1, 1972) was a Canadian-born American ecologist who made a major impact on many areas of community and population ecology. He is considered to be one of the founders of ecology. Early life and education MacArthur was born in Toronto, Ontario, to John Wood MacArthur and Olive Turner in 1930. He later moved to Marlboro, Vermont, as his father moved from the University of Toronto to Marlboro College. MacArthur received his Bachelor's degree in mathematics from Marlboro College, followed by a Master's degree in mathematics from Brown University in 1953. A student of G. Evelyn Hutchinson, MacArthur earned his Ph.D. from Yale University in 1957; his thesis was on the division of ecological niches among five warbler species in the conifer forests of Maine and Vermont. From 1957 to 1958, MacArthur worked as a postdoc with David Lack. Career MacArthur was a professor at the University of Pennsylvania, 1958–65, and professor o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Evolution And The Theory Of Games
''Evolution and the Theory of Games'' is a book by the British evolutionary biology, evolutionary biologist John Maynard Smith on evolutionary game theory. The book was initially published in December 1982 by Cambridge University Press. Overview In the book, John Maynard Smith summarises work on evolutionary game theory that had developed in the 1970s, to which he made several important contributions. The main contribution of the book is in introducing the concept of Evolutionarily Stable Strategy (ESS). ESS states that for a set of behaviours to be conserved over evolutionary time, they must be the most beneficial avenue of action when common, so that no alternative behaviour can invade. Supposing, for instance, that in a population of frogs, males fight to the death over breeding ponds. This would be an ESS if any one cowardly frog that does not fight to the death always fares worse (in terms of evolutionary survival fitness). A more likely scenario is one in which fighting to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Journal Of Theoretical Biology
The ''Journal of Theoretical Biology'' is a biweekly peer-reviewed scientific journal covering theoretical biology, as well as mathematical, computational, and statistical aspects of biology. Some research areas covered by the journal include cell biology, evolutionary biology, population genetics, morphogenesis, and immunology. The journal was established in 1961. Its founding editor-in-chief was English biologist James F. Danielli, who remained editor until his death in 1984. The journal is published by Elsevier and, , the editors-in-chief are Denise Kirschner ( University of Michigan Medical School), Mark Chaplain ( University of St. Andrews), and Akira Sasaki (The university for advanced studies, SOKENDAI, Hayama). Lewis Wolpert served as editor-in-chief for more than 55 years. According to the ''Journal Citation Reports'' the journal has a 2020 impact factor of 2.691. Notable articles The following are the most highly cited articles (more than 2,000 citations at April ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Mutant
In biology, and especially in genetics, a mutant is an organism or a new genetic character arising or resulting from an instance of mutation, which is generally an alteration of the DNA sequence of the genome or chromosome of an organism. It is a characteristic that would not be observed naturally in a specimen. The term mutant is also applied to a virus with an alteration in its nucleotide sequence whose genome is in the nuclear genome. The natural occurrence of genetic mutations is integral to the process of evolution. The study of mutants is an integral part of biology; by understanding the effect that a mutation in a gene has, it is possible to establish the normal function of that gene. Mutants arise by mutation Mutants arise by mutations occurring in pre-existing genomes as a result of errors of DNA replication or errors of DNA repair. Errors of replication often involve translesion synthesis by a DNA polymerase when it encounters and bypasses a damaged base in the te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which is intentional, whereas natural selection is not. Genetic diversity, Variation of traits, both Genotype, genotypic and phenotypic, exists within all populations of organisms. However, some traits are more likely to facilitate survival and reproductive success. Thus, these traits are passed the next generation. These traits can also become more Allele frequency, common within a population if the environment that favours these traits remains fixed. If new traits become more favoured due to changes in a specific Ecological niche, niche, microevolution occurs. If new traits become more favoured due to changes in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Fixation (population Genetics)
In population genetics, fixation is the change in a gene pool from a situation where there exists at least two variants of a particular gene (allele) in a given population to a situation where only one of the alleles remains. That is, the allele becomes fixed. In the absence of mutation or heterozygote advantage, any allele must eventually either be lost completely from the population, or fixed, i.e. permanently established at 100% frequency in the population. Whether a gene will ultimately be lost or fixed is dependent on selection coefficients and chance fluctuations in allelic proportions. Fixation can refer to a gene in general or particular nucleotide position in the DNA chain ( locus). In the process of substitution, a previously non-existent allele arises by mutation and undergoes fixation by spreading through the population by random genetic drift or positive selection. Once the frequency of the allele is at 100%, i.e. being the only gene variant present in any memb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ecological Stability
In ecology, an ecosystem is said to possess ecological stability (or equilibrium) if it is capable of returning to its equilibrium state after a perturbation (a capacity known as Ecological resilience, resilience) or does not experience unexpected large changes in its characteristics across time. Although the terms community stability and ecological stability are sometimes used interchangeably, community stability refers only to the characteristics of Community (ecology), communities. It is possible for an ecosystem or a community to be stable in some of their properties and unstable in others. For example, a vegetation community in response to a drought might conserve Biomass (ecology), biomass but lose biodiversity. Stable ecological systems abound in nature, and the scientific literature has documented them to a great extent. Scientific studies mainly describe grassland plant communities and microbial communities. Nevertheless, it is important to mention that not every communi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |