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  2. Thermodynamic activity - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_activity

    The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.

  3. Activity coefficient - Wikipedia

    en.wikipedia.org/wiki/Activity_coefficient

    In thermodynamics, an activity coefficient is a factor used to account for deviation of a mixture of chemical substances from ideal behaviour. [1] In an ideal mixture, the microscopic interactions between each pair of chemical species are the same (or macroscopically equivalent, the enthalpy change of solution and volume variation in mixing is zero) and, as a result, properties of the mixtures ...

  4. Chemical potential - Wikipedia

    en.wikipedia.org/wiki/Chemical_potential

    Thus, it is the partial derivative of the free energy with respect to the amount of the species, all other species' concentrations in the mixture remaining constant. When both temperature and pressure are held constant, and the number of particles is expressed in moles, the chemical potential is the partial molar Gibbs free energy .

  5. Relative species abundance - Wikipedia

    en.wikipedia.org/wiki/Relative_species_abundance

    Relative species abundance is a component of biodiversity and is a measure of how common or rare a species is relative to other species in a defined location or community. [1] Relative abundance is the percent composition of an organism of a particular kind relative to the total number of organisms in the area.

  6. Abundance (ecology) - Wikipedia

    en.wikipedia.org/wiki/Abundance_(ecology)

    In ecology, local abundance is the relative representation of a species in a particular ecosystem. [1] It is usually measured as the number of individuals found per sample. The ratio of abundance of one species to one or multiple other species living in an ecosystem is referred to as relative species abundances. [1]

  7. Biodiversity - Wikipedia

    en.wikipedia.org/wiki/Biodiversity

    Species evenness is the relative number of individuals of each species in a given area. [181] Species richness [182] is the number of species present in a given area. Species diversity [183] is the relationship between species evenness and species richness. There are many ways to measure biodiversity within a given ecosystem.

  8. Interspecific competition - Wikipedia

    en.wikipedia.org/wiki/Interspecific_competition

    Subadult male lion and female spotted hyena in the Masai Mara.The two species share the same ecological niche, and are thus in competition with each other. Interspecific competition, in ecology, is a form of competition in which individuals of different species compete for the same resources in an ecosystem (e.g. food or living space).

  9. Occupancy–abundance relationship - Wikipedia

    en.wikipedia.org/wiki/Occupancy–abundance...

    In ecology, the occupancy–abundance (O–A) relationship is the relationship between the abundance of species and the size of their ranges within a region. This relationship is perhaps one of the most well-documented relationships in macroecology, and applies both intra- and interspecifically (within and among species).