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Rarefaction (ecology)
In ecology, rarefaction is a technique to assess species richness from the results of sampling. Rarefaction allows the calculation of species richness for a given number of individual samples, based on the construction of so-called rarefaction curves. This curve is a plot of the number of species as a function of the number of samples. Rarefaction curves generally grow rapidly at first, as the most common species are found, but the curves plateau as only the rarest species remain to be sampled. The issue that occurs when sampling various species in a community is that the larger the number of individuals sampled, the more species that will be found. Rarefaction curves are created by randomly re-sampling the pool of ''N'' samples multiple times and then plotting the average number of species found in each sample (1,2, ... N). "Thus rarefaction generates the expected number of species in a small collection of ''n'' individuals (or ''n'' samples) drawn at random from the large pool of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history. Ecology is a branch of biology, and it is not synonymous with environmentalism. Among other things, ecology is the study of: * The abundance, biomass, and distribution of organisms in the context of the environment * Life processes, antifragility, interactions, and adaptations * The movement of materials and energy through living communities * The successional development of ecosystems * Cooperation, competition, and predation within and between species * Patterns of biodiversity and its effect on ecosystem processes Ecology has practical applications in conservation biology, wetland management, natural resource managemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Richness
Species richness is the number of different species represented in an ecological community, landscape or region. Species richness is simply a count of species, and it does not take into account the abundances of the species or their relative abundance distributions. Species richness is sometimes considered synonymous with species diversity, but the formal metric species diversity takes into account both species richness and species evenness. Sampling considerations Depending on the purposes of quantifying species richness, the individuals can be selected in different ways. They can be, for example, trees found in an inventory plot, birds observed from a monitoring point, or beetles collected in a pitfall trap. Once the set of individuals has been defined, its species richness can be exactly quantified, provided the species-level taxonomy of the organisms of interest is well enough known. Applying different species delimitations will lead to different species richness values ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sampling (statistics)
In statistics, quality assurance, and survey methodology, sampling is the selection of a subset (a statistical sample) of individuals from within a statistical population to estimate characteristics of the whole population. Statisticians attempt to collect samples that are representative of the population in question. Sampling has lower costs and faster data collection than measuring the entire population and can provide insights in cases where it is infeasible to measure an entire population. Each observation measures one or more properties (such as weight, location, colour or mass) of independent objects or individuals. In survey sampling, weights can be applied to the data to adjust for the sample design, particularly in stratified sampling. Results from probability theory and statistical theory are employed to guide the practice. In business and medical research, sampling is widely used for gathering information about a population. Acceptance sampling is used to determine if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Howard Sanders
Howard is an English-language given name originating from Old French Huard (or Houard) from a Germanic source similar to Old High German ''*Hugihard'' "heart-brave", or ''*Hoh-ward'', literally "high defender; chief guardian". It is also probably in some cases a confusion with the Old Norse cognate ''Haward'' (''Hávarðr''), which means "high guard" and as a surname also with the unrelated Hayward. In some rare cases it is from the Old English ''eowu hierde'' "ewe herd". In Anglo-Norman the French digram ''-ou-'' was often rendered as ''-ow-'' such as ''tour'' → ''tower'', ''flour'' (western variant form of ''fleur'') → ''flower'', etc. (with svarabakhti). A diminutive is "Howie" and its shortened form is "Ward" (most common in the 19th century). Between 1900 and 1960, Howard ranked in the U.S. Top 200; between 1960 and 1990, it ranked in the U.S. Top 400; between 1990 and 2004, it ranked in the U.S. Top 600. People with the given name Howard or its variants include: Given ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stuart Hurlbert
Stuart may refer to: Names *Stuart (name), a given name and surname (and list of people with the name) Automobile *Stuart (automobile) Places Australia Generally *Stuart Highway, connecting South Australia and the Northern Territory Northern Territory *Stuart, the former name for Alice Springs (changed 1933) * Stuart Park, an inner city suburb of Darwin *Central Mount Stuart, a mountain peak Queensland *Stuart, Queensland, a suburb of Townsville *Mount Stuart, Queensland, a suburb of Townsville *Mount Stuart (Queensland), a mountain South Australia *Stuart, South Australia, a locality in the Mid Murray Council *Electoral district of Stuart, a state electoral district *Hundred of Stuart, a cadastral unit Canada *Stuart Channel, a strait in the Gulf of Georgia region of British Columbia United Kingdom *Castle Stuart United States *Stuart, Florida *Stuart, Iowa *Stuart, Nebraska *Stuart, Oklahoma *Stuart, Virginia *Stuart Township, Holt County, Nebraska *Stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniel Simberloff
Daniel Simberloff is a biologist and ecologist who earned his Ph.D. from Harvard University in 1969. He is currently Gore Hunger Professor of Environmental Science at the University of Tennessee, editor-in-chief of the journal ''Biological Invasions'', and a member of the National Academy of Sciences. Early life and education Simberloff was born in 1942 in Wilson Borough, Pennsylvania. As a young child, he collected insects, especially beetles, pinning and preserving them in cigar boxes as early as four years old. In addition to his collection of insects, Simberloff also caught and kept salamanders and musk turtles in a basin in his home. He cites being influenced by his uncle, who was a chemist. Consequently, he received science books and was taken to science lectures throughout his youth. He moved to New York City at age 11. Simberloff received his Bachelor of Arts from Harvard College in 1964, and his Ph.D. in Biology from Harvard University in 1969. He wanted to go to gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymptote
In analytic geometry, an asymptote () of a curve is a line such that the distance between the curve and the line approaches zero as one or both of the ''x'' or ''y'' coordinates tends to infinity. In projective geometry and related contexts, an asymptote of a curve is a line which is tangent to the curve at a point at infinity. The word asymptote is derived from the Greek ἀσύμπτωτος (''asumptōtos'') which means "not falling together", from ἀ priv. + σύν "together" + πτωτ-ός "fallen". The term was introduced by Apollonius of Perga in his work on conic sections, but in contrast to its modern meaning, he used it to mean any line that does not intersect the given curve. There are three kinds of asymptotes: ''horizontal'', ''vertical'' and ''oblique''. For curves given by the graph of a function , horizontal asymptotes are horizontal lines that the graph of the function approaches as ''x'' tends to Vertical asymptotes are vertical lines near which the fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Diversity
Beta (, ; uppercase , lowercase , or cursive ; grc, βῆτα, bē̂ta or ell, βήτα, víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Modern Greek, it represents the voiced labiodental fricative while in borrowed words is instead commonly transcribed as μπ. Letters that arose from beta include the Roman letter and the Cyrillic letters and . Name Like the names of most other Greek letters, the name of beta was adopted from the acrophonic name of the corresponding letter in Phoenician, which was the common Semitic word ''*bait'' ('house'). In Greek, the name was ''bêta'', pronounced in Ancient Greek. It is spelled βήτα in modern monotonic orthography and pronounced . History The letter beta was derived from the Phoenician letter beth . Uses Algebraic numerals In the system of Greek numerals, beta has a value of 2. Such use is denoted by a number mark: Β′. Computing Finance Beta is used i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extrapolate
In mathematics, extrapolation is a type of estimation, beyond the original observation range, of the value of a variable on the basis of its relationship with another variable. It is similar to interpolation, which produces estimates between known observations, but extrapolation is subject to greater uncertainty and a higher risk of producing meaningless results. Extrapolation may also mean extension of a method, assuming similar methods will be applicable. Extrapolation may also apply to human experience to project, extend, or expand known experience into an area not known or previously experienced so as to arrive at a (usually conjectural) knowledge of the unknownExtrapolation entry at Merriam–Webster (e.g. a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodiversity
Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') level. Biodiversity is not distributed evenly on Earth; it is usually greater in the tropics as a result of the warm climate and high primary productivity in the region near the equator. Tropical forest ecosystems cover less than 10% of earth's surface and contain about 90% of the world's species. Marine biodiversity is usually higher along coasts in the Western Pacific, where sea surface temperature is highest, and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, but will be likely to slow in the future as a primary result of deforestation. It encompasses the evolutionary, ecological, and cultural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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