Search results
Results from the WOW.Com Content Network
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 ...
Behavioral sink. " Behavioral sink " is a term invented by ethologist John B. Calhoun to describe a collapse in behavior that can result from overpopulation. The term and concept derive from a series of over-population experiments Calhoun conducted on Norway rats between 1958 and 1962. [1] In the experiments, Calhoun and his researchers created ...
Demographic economics or population economics is the application of economic analysis to demography, the study of human populations, including size, growth, density, distribution, and vital statistics. [1] [2]
This is a list of countries and dependencies ranked by population density, sorted by inhabitants per square kilometre or square mile. The list includes sovereign states and self-governing dependent territories based upon the ISO standard ISO 3166-1. The list also includes unrecognized but de facto independent countries.
The physiological density or real population density is the number of people per unit area of arable land . A higher physiological density suggests that the available agricultural land is being used by more and may reach its output limit sooner than a country that has a lower physiological density. Egypt is a notable example, with physiological ...
Population size. In population genetics and population ecology, population size (usually denoted N) is a countable quantity representing the number of individual organisms in a population. Population size is directly associated with amount of genetic drift, and is the underlying cause of effects like population bottlenecks and the founder ...
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 population dynamics. [2]
Source–sink dynamics is a theoretical model used by ecologists to describe how variation in habitat quality may affect the population growth or decline of organisms . Since quality is likely to vary among patches of habitat, it is important to consider how a low quality patch might affect a population. In this model, organisms occupy two ...