Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement. In biology, the term population growth is likely to refer to any known organism, but this article deals mostly with the application of the term to human populations in demography.
In demography, population growth is used informally for the more specific term population growth rate (see below), and is often used to refer specifically to the growth of the human population of the world.
Simple models of population growth include the Malthusian Growth Model and the logistic model.
Population growth 1800-2011: from 1 billion to 7 billion estimated in 31.10.2011. During the year 2011, according to estimates:
- 135 million people were born
- 57 million people died
- 78 million people increased the world population.
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