Birth Rate: Measure of an area's fertility. Number of live births per 1,000 people in 1 year.
Death Rate: Number of deaths per 1,000 people in 1 year.
Life Expectancy: Average number of years from birth that a person can expect to live.
Longevity: Increase in life expectancy over a period of time. A direct result of improved medical provision and increased economic development. People live longer creating an older population.
Natural Change: Change in size of a population caused by the interrelationship between birth and death rates. If birth rate exceeds death rate population increases. If death rate exceeds birth rate population declines.
Fertility: Number of live birth per 1,000 women aged 15-49 in 1 year. Also defined as the average number of children each woman in a population will have. If it's 2.1 or higher a population will replace itself.
Infant Mortality Rate: Number of deaths of children under the age of 1 year expressed per 1,000 live births per year.
Forced Migration: Migrant has to migrate because of circumstances.
Internation Migration: The UN defines international migration as the movement of people across national frontiers for a minimum of a year.
Migration: Permanent or semi-permanent change of residence of an individual or group of people.
Net Migration: Difference between the numbers of in-migrants and out-migrants of an area. When in-migrants succeed out-migrants net migrational gain. Out-migrants exceeds in-migrants net migrational loss.
Rural-urban and urban-rural migration: In less developed countries, net migrational gain of urban areas at the expense of rural areas results in urbanisation. MEDCs movements from urban to rural have led to counter-urbanisation.
Voluntary Migration: Migrant makes the decision to migrate.
Population Structure: Proportion of males and females in an area, usually in the form of age distributions.
Population Density: Number of people in an area. Density of population is obtained by dividing the total population of a country by the total area of that country.
Overpopulation: When there are too many people in an area relative to the amount of resources and the level of technology available locally to maintain a high standard of living.