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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 ...
John B. Calhoun. John Calhoun (age 69) in the fall of 1986 at the baby shower of his first grandchild. John Bumpass Calhoun (May 11, 1917 – September 7, 1995) was an American ethologist and behavioral researcher noted for his studies of population density and its effects on behavior. He claimed that the bleak effects of overpopulation on ...
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 ...
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 ...
The females in the same population have the same throat colours, and this affects how many offspring they produce and the size of the progeny, which generates cycles in density, yet another game – the r-K game. Here, r is the Malthusian parameter governing exponential growth, and K is the carrying capacity of the environment.
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.
Population momentum explains why a population will continue to grow even if the fertility rate declines. Population momentum occurs because it is not only the number of children per woman that determine population growth, but also the number of women in reproductive age. Eventually, when the fertility rate reaches the replacement rate and the ...
Malthusianism. Malthusianism is the theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of triggering a population decline. This event, called a Malthusian catastrophe (also ...