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Population density is the number of people per unit of area, usually transcribed as "per square kilometer" or square mile, and which may include or exclude, for example, areas of water or glaciers. Commonly this is calculated for a county, city, country, another territory or the entire world. The world's population is around 8,000,000,000 [3 ...
A population is defined as a group of interacting organisms of the same species. A demographic structure of a population is how populations are often quantified. The total number of individuals in a population is defined as a population size, and how dense these individuals are is defined as population density.
Allee effects are classified by the nature of density dependence at low densities. If the population shrinks for low densities, there is a strong Allee effect. If the proliferation rate is positive and increasing then there is a weak Allee effect. The null hypothesis is that proliferation rates are positive but decreasing at low densities.
[16] For example, in a closed system where immigration and emigration does not take place, the rate of change in the number of individuals in a population can be described as: = = = =, where N is the total number of individuals in the specific experimental population being studied, B is the number of births and D is the number of deaths per ...
Population. Population is the term typically used to refer to the number of people in a single area. Governments conduct a census to quantify the size of a resident population within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and plants, and has specific uses within such fields as ecology and genetics.
Malthusian growth model. A Malthusian growth model, sometimes called a simple exponential growth model, is essentially exponential growth based on the idea of the function being proportional to the speed to which the function grows. The model is named after Thomas Robert Malthus, who wrote An Essay on the Principle of Population (1798), one of ...
Species distribution, or species dispersion, [1] is the manner in which a biological taxon is spatially arranged. [2] 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 ...
Population biology. The term population biology has been used with different meanings. In 1971, Edward O. Wilson et al. used the term in the sense of applying mathematical models to population genetics, community ecology, and population dynamics. [1] Alan Hastings used the term in 1997 as the title of his book on the mathematics used in ...