Population Size
Method of Calculation
The study of population statistics is called demography. Since 1801 a population census (survey) of the UK has been held every ten years to count the number of people in the country.
A census is carried out because the government needs to plan ahead. The figures can be used to estimate the number of roads, schools, hospitals etc likely to be needed in the future.
Birth Rate
The crude birth rate is the number of births per thousand of the population in a year. The birth rate has fallen from 28.6 in 1900 to 12.8 in 1988. This dramatic fall has been caused by:
Improved birth control. Contraceptives are now more available and socially accepted.
Women choosing to continue working, or waiting before raising smaller families.
Death Rate
The death rate is the number of deaths per thousand of the population in a year. The death rate has fallen from 18.4 in 1900 to 11.7 in 1988. This fall has been caused by:
Improved housing, diet and sanitation.
Improved health care through medical discoveries and introduction of the National Health Service.
Migration
Migration happens when people either permanently leave a country (emigration) or enter it (immigration). Net migration is the difference between the number of people emigrating and immigrating.
People usually want to leave countries (voluntary emigration) for two reasons:
Push factors which include high unemployment, low living standards or poor climate in their own country.
Pull factors which include good job prospects and high living standards in a new country.
Population Structure
Population Structure by Sex and Age
Population pyramids can be used to show the sex and age structure of a particular country. Developed countries tend to have an even sex and age structure while less developed ones have over half their population aged under 16.
An ageing population occurs when the average age per person is rising.
Population Structure by Area
There is an uneven spread of population about the country because:
Some areas are remote, hilly or uninhabitable.
Farming areas employ few people.
Industry is concentrated in towns.
80 per cent of the UK population live in England, largely in the south-east and midlands. 80 percent of people live in urban (built-up) areas. 20 cities have a population of more than 250 000. The seven UK conurbations (several towns joined together) house a third of the population but they occupy only 3 per cent of the land area. Move away from living in the inner cities.
Optimum Population
T R Malthus
Writing at the end of the eighteenth century, Malthus argued that:
Population rises in a geometric way, ie 1,2,4,8,16.
The food supply rises arithmetically, ie 1,2,3,4,5.
Only way, famine and plague would prevent absolute poverty.
Malthus did not take into account the spread of birth-control techniques which reduced the rate of population growth. Malthus also overlooked the effects of future farming inventions, and the development of foreign trade which dramatically increased the food supply.
Optimum Population
Optimum (best) population occurs when productivity (output per person) is highest.
An under-populated country can increase productivity by increasing its population.
An over-populated country can increase productivity by reducing its population