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Idealised Population
In population genetics an idealised population is one that can be described using a number of simplifying assumptions. Models of idealised populations are either used to make a general point, or they are fit to data on real populations for which the assumptions may not hold true. For example, coalescent theory is used to fit data to models of idealised populations. The most common idealized population in population genetics is described in the Wright-Fisher model after Sewall Wright and Ronald Fisher (1922, 1930) and (1931). Wright-Fisher populations have constant size, and their members can mate and reproduce with any other member. Another example is a Moran model, which has overlapping generations, rather than the non-overlapping generations of the Fisher-Wright model. The complexities of real populations can cause their behavior to match an idealised population with an effective population size that is very different from the census population size of the real population. For se ... [...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] |
Joe Roman
Joe Roman is a conservation biologist, academic, and author of the books ''Whale'' and '' Listed: Dispatches from America's Endangered Species Act''. His conservation research includes studies of the historical population size of whales, the role of cetaceans in the nitrogen cycle, the relationship between biodiversity and disease, and the genetics of invasions. He is the founding editor of "Eat the Invaders", a website dedicated to controlling invasive species by eating them. Roman is a research associate professor in the Rubenstein School of Environment and Natural Resources and a Fellow at the Gund Institute for Ecological Economics at the University of Vermont. He earned an AB with Honors in Visual and Environmental Studies from Harvard University in 1985 and an MA in wildlife ecology and conservation from the University of Florida. Roman was awarded his PhD from Harvard's Department of Organismic and Evolutionary Biology in 2003; his dissertation was titled ''Tracking ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Program
A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program in its human-readable form is called source code. Source code needs another computer program to execute because computers can only execute their native machine instructions. Therefore, source code may be translated to machine instructions using the language's compiler. ( Assembly language programs are translated using an assembler.) The resulting file is called an executable. Alternatively, source code may execute within the language's interpreter. If the executable is requested for execution, then the operating system loads it into memory and starts a process. The central processing unit will soon switch to this process so it can fetch, decode, and then execute each machine instruction. If the source code is requested for execution, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simulation
A simulation is the imitation of the operation of a real-world process or system over time. Simulations require the use of Conceptual model, models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Often, computers are used to execute the computer simulation, simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games. Simulation is also used with scientific modelling of natural systems or human systems to gain insight into their functioning, as in economics. Simulation can be used to show the eventual real effects of alternative conditions and courses of action. Simulation is also used when the real system cannot be engaged, because it may not be accessible, or it may be dangerous or unacceptable to engage, or it is being designed bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stepping Stone Model
Stepping may refer to: * Walking, one of the main gaits of locomotion among legged animals Computing * Stepping level, an aspect of microprocessor version designation * Stepping (debugging), a method of debugging Dance * Chicago stepping, a type of dance originating in Chicago * Step dance, generic term for dance styles where the footwork is the most important part of the dance * Stepping (African-American), a percussive dance in which the participant's entire body is used as an instrument * ''Steppin''', album by the Pointer Sisters See also * Step (other) * Stepping stone (other) * Mast Stepping {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaic Human Admixture With Modern Humans
There is evidence for interbreeding between archaic and modern humans during the Middle Paleolithic and early Upper Paleolithic. The interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins. In Eurasia, interbreeding between Neanderthals and Denisovans with modern humans took place several times. The introgression events into modern humans are estimated to have happened about 47,000–65,000 years ago with Neanderthals and about 44,000–54,000 years ago with Denisovans. Neanderthal-derived DNA has been found in the genomes of most or possibly all contemporary populations, varying noticeably by region. It accounts for 1–4% of modern genomes for people outside Sub-Saharan Africa, although estimates vary, and either none or possibly up to 0.3% — according to recent research — for those in Africa. It is highest in East Asians, intermediate in Europeans, and lower in Southeast Asians. According to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science (journal)
''Science'', also widely referred to as ''Science Magazine'', is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. ''Science'' is based in Washington, D.C., United States, with a second office in Cambridge, UK. Contents The major focus of the journal is publishing important original scientific research and research reviews, but ''Science'' also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, ''Science'' and its rival ''Nature (journal), Nature'' c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex Ratio
The sex ratio (or gender ratio) is usually defined as 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. Many species deviate from an even sex ratio, either periodically or permanently. Examples include parthenogenic species, periodically mating organisms such as aphids, some eusocial wasps, bees, ants, and termites. The human sex ratio is of particular interest to anthropologists and demographers. In human societies, sex ratios at birth may be considerably skewed by factors such as the age of mother at birth and by sex-selective abortion and infanticide. Exposure to pesticides and other environmental contaminants may be a significant contributing factor as well. As of 2014, the global sex ratio at birth is estimated at 107 boys to 100 girls (1,000 boys per 934 girls).. Types In most species, the sex ratio varies according to the age profile of the populat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Population
The effective population size (''N''''e'') is a number that, in some simplified scenarios, corresponds to the number of breeding individuals in the population. More generally, ''N''''e'' is the number of individuals that an idealised population would need to have in order for some specified quantity of interest (typically change of genetic diversity or inbreeding rates) to be the same as in the real population. Idealised populations are based on unrealistic but convenient simplifications such as random mating, simultaneous birth of each new generation, constant population size, and equal numbers of children per parent. For most quantities of interest and most real populations, the effective population size ''N''''e'' is usually smaller than the census population size ''N'' of a real population. The same population may have multiple effective population sizes, for different properties of interest, including for different genetic loci. The effective population size is most commonly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from ''genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitutions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephen R
Stephen or Steven is a common English given name, first name. It is particularly significant to Christianity, Christians, as it belonged to Saint Stephen ( grc-gre, Στέφανος ), an early disciple and deacon who, according to the Book of Acts, was stoned to death; he is widely regarded as the first martyr (or "protomartyr") of the Christian Church. In English, Stephen is most commonly pronounced as ' (). The name, in both the forms Stephen and Steven, is often shortened to Steve or Stevie (given name), Stevie. The spelling as Stephen can also be pronounced which is from the Greek original version, Stephanos. In English, the female version of the name is Stephanie. Many surnames are derived from the first name, including Template:Stephen-surname, Stephens, Stevens, Stephenson, and Stevenson, all of which mean "Stephen's (son)". In modern times the name has sometimes been given with intentionally non-standard spelling, such as Stevan or Stevon. A common variant of the name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binomial Square Principle
Binomial may refer to: In mathematics *Binomial (polynomial), a polynomial with two terms *Binomial coefficient, numbers appearing in the expansions of powers of binomials *Binomial QMF, a perfect-reconstruction orthogonal wavelet decomposition *Binomial theorem, a theorem about powers of binomials *Binomial type, a property of sequences of polynomials In probability and statistics *Binomial distribution, a type of probability distribution *Binomial process *Binomial test, a test of significance In computing science *Binomial heap, a data structure In linguistics *Binomial pair, a sequence of two or more words or phrases in the same grammatical category, having some semantic relationship and joined by some syntactic device In biology * Binomial nomenclature, a Latin two-term name for a species, such as ''Sequoia sempervirens'' In finance *Binomial options pricing model, a numerical method for the valuation of options In politics * Binomial voting system, a voting system used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
