POPULATION

VOCABULARY

BIRTH RATE: number of births that take place in a population over a year.
DEATH RATE: number of deaths that take place in a population over a year.
NATURAL INCREASE: crude birth rates minus the crude desth rate. 
INFANT MORTALITY RATE: is the number of deaths of infants under 1 year dividing by the number of births in a year, per 100.
LIFE EXPECTANCY:  is the average years that one person may expect to live.
BIRTH CONTROL: methods of restricting the number of children born.
DEPENDENT POPULATION:  part of the population that does not work and relies on others for the goods and services they consume. 
DEPENDENCY RATIO: measure showing the number of dependents, aged zero to 14 and over the age of 65, to the total population, aged 15 to 64.
FAMILY PLANNING:  is the practice of controlling the number of children in a family and the intervals between their births, particularly by means of artificial contraception or voluntary sterilization. 
POPULATION PIRAMIDS/ AGE-GENDER STRUCTURE: is one way to look at the demographics of a country. .
REPLACEMENT RATE: A replacement rate is the percentage of a worker's pre-retirement income that is paid out by a pension program upon retirement.
FERTILITY RATE: the ratio of live births in an area to the population of that area; expressed per 1000 population per year.
AGEING  POPULATION:  is a phenomenon that occurs when the median age of a country or region rises due to rising life expectancy and declining birth rates.
POPULATION DISTRIBUTION: the arrangement or spread of people living in a given area.
POPULATION DENSITY: is a measurement of population per unit area or unit volume.
MEDC: is a sovereign state that has a highly developed economy and advanced technological infrastructure relative to other less industrialized nations..
LEDC: is a nation or sovereign state with a less developed industrial base and a low Human Development Index (HDI) relative to other countries.
OVERPOPULATION: occurs when a species' population exceeds the carrying capacity of its ecological niche.
UNDER POPULATION: can refer to the decline in population of any organism, but this article refers to population decline in humans.