英和和英

The interaction of fertility, mortality and migration leads to a consideration of population growth ¹. It is convenient to regard population decline ² as negative growth ³. A distinction may be drawn between a closed population ⁴ in which there is no migration either inwards or outwards and whose growth depends entirely on the difference between births and deaths, and an open population ⁵ in which there may be migration. The growth of an open population consists of the balance of migration ⁶ or net migration ⁶ and natural increase ⁷, which is the excess of births over deaths ⁸, sometimes called the balance of births and deaths ⁸.

• 1. Zero population growth refers to a population of invariable size.

More...