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Hutchinson's Ratio
In ecological theory, the Hutchinson's ratio is the ratio of the size differences between similar species when they are living together as compared to when they are isolated. It is named after G. Evelyn Hutchinson who concluded that various key attributes in species varied according to the ratio of 1:1.1 to 1:1.4. Hutchinson concluded that the mean ratio, 1.3, can be understood as the variation of attribute separation needed in order to preserve species coexistence at the same trophic level but in differing niches. However, some authors present evidence that this ratio does not depict the structure of animal communities. Rather, Hutchinson's ratio is just a representation of the distribution Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ... of entities, both living and non-living, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecology
Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere levels. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history. Ecology is a branch of biology, and is the study of abundance (ecology), abundance, biomass (ecology), biomass, and distribution of organisms in the context of the environment. It encompasses life processes, interactions, and adaptations; movement of materials and energy through living communities; ecological succession, successional development of ecosystems; cooperation, competition, and predation within and between species; and patterns of biodiversity and its effect on ecosystem processes. Ecology has practical applications in fields such as conservation biology, wetland management, natural resource m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ratio
In mathematics, a ratio () shows how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ratio 4:3). Similarly, the ratio of lemons to oranges is 6:8 (or 3:4) and the ratio of oranges to the total amount of fruit is 8:14 (or 4:7). The numbers in a ratio may be quantities of any kind, such as counts of people or objects, or such as measurements of lengths, weights, time, etc. In most contexts, both numbers are restricted to be Positive integer, positive. A ratio may be specified either by giving both constituting numbers, written as "''a'' to ''b''" or "''a'':''b''", or by giving just the value of their quotient Equal quotients correspond to equal ratios. A statement expressing the equality of two ratios is called a ''proportion''. Consequently, a ratio may be considered as an ordered pair of numbers, a Fraction (mathematic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophic Level
The trophic level of an organism is the position it occupies in a food web. Within a food web, a food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it is from the start of the chain. A food web starts at trophic level 1 with primary producers such as plants, can move to herbivores at level 2, carnivores at level 3 or higher, and typically finish with apex predators at level 4 or 5. The path along the chain can form either a one-way flow or a part of a wider food "web". Ecological communities with higher biodiversity form more complex trophic paths. The word ''trophic'' derives from the Ancient Greek, Greek wikt:τροφή, τροφή (trophē) referring to food or nourishment. History The concept of trophic level was developed by Raymond Lindeman (1942), based on the terminology of August Thienemann (1926): "producers", "consumers", and "reducers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distribution (ecology)
Species distribution, or species dispersion, is the manner in which a biological taxon is spatially arranged. The geographic limits of a particular taxon's distribution is its range, often represented as shaded areas on a map. Patterns of distribution change depending on the scale at which they are viewed, from the arrangement of individuals within a small family unit, to patterns within a population, or the distribution of the entire species as a whole (range). Species distribution is not to be confused with dispersal, which is the movement of individuals away from their region of origin or from a population center of high density. Range In biology, the range of a species is the geographical area within which that species can be found. Within that range, distribution is the general structure of the species population, while dispersion is the variation in its population density. Range is often described with the following qualities: * Sometimes a distinction is made between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hutchinson's Rule
In ecological theory, the Hutchinson's ratio is the ratio of the size differences between similar species when they are living together as compared to when they are isolated. It is named after G. Evelyn Hutchinson who concluded that various key attributes in species varied according to the ratio of 1:1.1 to 1:1.4. The mean ratio 1.3 can be interpreted as the amount of separation necessary to obtain coexistence of species at the same trophic level. The variation in trophic structures of sympatric congeneric species is presumed to lead to niche differentiation, and allowing coexistence of multiple similar species in the same habitat by the partitioning of food resources. Hutchinson concluded that this size ratio could be used as an indicator of the kind of difference necessary to permit two species to co-occur in different niches but at the same level of the food web. The rule's legitimacy has been questioned, as other categories of objects also exhibit size ratios of roughly 1.3. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
