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Population distribution by age and sex for Angola in 2005. A population pyramid (age structure diagram) or "age-sex pyramid" is a graphical illustration of the distribution of a population (typically that of a country or region of the world) by age groups and sex; it typically takes the shape of a pyramid when the population is growing. [1]
Population control is the practice of artificially maintaining the size of any population. It simply refers to the act of limiting the size of an animal population so that it remains manageable, as opposed to the act of protecting a species from excessive rates of extinction, which is referred to as conservation biology. [1] [2] [3]
The most significant population planning system in the world was China's one-child policy, in which, with various exceptions, having more than one child was discouraged. Unauthorized births were punished by fines, although there were also allegations of illegal forced abortions and forced sterilization . [ 57 ]
An example of using age class structure to learn about a population is a regular bell curve for the population of 1-5 year-old fish with a very low population for the 3-year-olds. An age class structure with gaps in population size like the one described earlier implies a bad spawning year 3 years ago in that species. [7]
Population structure may refer to many aspectsof population ecology: Population structure (genetics) , also called population stratification Population pyramid
Population momentum is a consequence of the demographic transition. Population momentum explains why a population will continue to grow even if the fertility rate declines or continues to decline even if the fertility rate grows. Population momentum occurs because it is not only the number of children per woman that determine population growth ...
Population models are used to determine maximum harvest for agriculturists, to understand the dynamics of biological invasions, and for environmental conservation. Population models are also used to understand the spread of parasites, viruses, and disease. [2] Another way populations models are useful are when species become endangered.
In ecology, a population is a group of organisms of the same species which inhabit the same geographical area and are capable of interbreeding. [2] [3] The area of a sexual population is the area where interbreeding is possible between any opposite-sex pair within the area and more probable than cross-breeding with individuals from other areas.