Population

POPULATION GROWTH

Population change - the difference between the birth rate and the death rate

Birth rate - the number of babies born per 1000 people per year in a population

Death rate - the number of deaths per 1000 people per year in a population

Fertility rate - the average number of children a woman will give birth to

Replacement rate - the number of children that would need to be born to replace the present population

A youthful population - a population where a large proportion of the population is under 15

An ageing population - a population where the median age of a population rises

We can see from the graph of global population from 1500-2000 that the world's population has increased dramatically, and is still increasing today.  The rate at which the world's population is increasing is getting more rapid.  When the birth rate is higher than the death rate, this is called natural increase.  The population grows.  When the birth rate is lower than the death rate, this is called natural decrease.  The population size of a country is also affected by migration.

Population distribution describes the way that people are spread out over the Earth's surface.  Population density is a numerical measure that describes the number of people living in a given area, usually a km2.

Density = total population / area

FACTORS THAT AFFECT POPULATION DISTRIBUTION

Physical factors:

• Relief
• Soils
• Vegetation
• Temperature
• Rainfall
• Natural resources
• Water supply

At a large scale, physical factors generally determine population distribution.

Human factors:

• Transport and infrastructure
• Ports and trading routes
• Tourism
• Government policies

These factors are more important at a smaller scale.

THE DEMOGRAPHIC TRANSITION MODEL

Birth rates and death rates different from country to country.  Population change is faster in some countries than others.  Population growth changes in a country over time.  Countries go through five stages of population growth.  These stages are shown by the Demographic Transition Model (DTM).

Stage 1 - the birth rate is high and fluctuating.  The death rate is also high and fluctuating.  The population growth rate is zero and the population size is low and steady.  eg Brazilian tribes

Stage 2 - the birth rate is high and steady.  The death rate…