Slides in this set
· Population density is the average number of people per square kilometre. It is a way of measuring
population distribution and shows whether an area is sparsely or densely populated. Population
density is calculated using the following formula:
· Population density = total population ÷ total land area in km²
Factors attracting settlement
· Temperate climate, eg the UK.
· Low-lying flat fertile land, eg the Bangladesh Delta.
· Good supplies of natural resources, eg building resources.
Factors discouraging settlement
· Extreme climates, eg Sahara Desert.
· Mountainous or highland areas, eg the Scottish Highlands.
· Dense vegetation, eg the Amazon Rainforest.
· Factors such as the availability of jobs and comparatively high wages can contribute to high population
density through migration. For example, from 2004 the UK has seen an influx of migrants from
countries that have recently joined the EU, such as Poland.
· Civil war, eg in the Darfur region of Sudan, can contribute to lower population densities as people
become refugees and leave an area.…read more
Causes and rates of change
· The three main causes of population change are:
· Births - usually measured using the birth rate (number of live births per 1000 of the population).
· Deaths - usually measured using the death rate (number of deaths per 1000 of the population) .
· Migration - the movement of people in and out of an area.
Rate of change
· Births and deaths are natural causes of population change. The difference between the birth rate and
the death rate of a country or place is called the natural increase. The natural increase is calculated by
subtracting the death rate from the birth rate.
· natural increase = birth rate - death rate
Patterns of population growth
· Rates of population growth vary across the world. Although the world's total population is rising
rapidly, not all countries are experiencing this growth. In the UK, for example, population growth is
slowing, while in Germany the population has started to decline. MEDCs have low population growth
rates, with low death rates and low birth rates.
· Population will decline if death rate is greater than birth rate.
· LEDCs have high population growth rates. Both birth rates and death rates in LEDCs tend to be high.
However, improving healthcare leads to death rates falling - while birth rates remain high.
· Population will increase if death rate is less than birth rate.
· The table shows data in selected LEDC and MEDC countries. The figures are per 1000 of the population
per year.…read more
The demographic transition model
The demographic transition model shows population change over time. It studies how birth rate and death
rate affect the total population of a country. It is divided into five stages:
1) Total population is low but it is balanced due to high birth rates and high death rates.
2) Total population rises as death rates fall due to improvements in health care and sanitation. Birth rates
3) Total population is still rising rapidly. The gap between birth and death rates narrows due to the
availability of contraception and fewer children being needed to work - due to the mechanisation of
farming. The natural increase is high.
4) Total population is high, but it is balanced by a low birth rate and a low death rate. Birth control is
widely available and there is a desire for smaller families.
5) Total population is high but going into decline due to an ageing population. There is a continued desire
for smaller families, with people opting to have children later in life.
Limitations of the model
6) The demographic transition model has two limitations:
7) The model was developed after studying the experiences
8) of countries in Western Europe and North America.
9) Conditions might be different for LEDCs in different
10) parts of the world.
11) The original model doesn't take into account the act
12) that some countries now have a declining population
13) and a 5th stage. Most texts will now show this stage
14) as it is relevant to an increasing number of MEDCs
15) in the 21st century.…read more
Analysing population pyramids
· Key things to know about population pyramids:
· The shape of a population pyramid can tell us a lot about an area's population.
· It gives us information about birth and death rates as well as life expectancy.
· A population pyramid tells us how many dependants there are. There are two groups of dependants;
young dependants (aged below 15) and elderly dependants (aged over 65).
· Dependants rely upon the economically active for economic support.
· Many LEDCs have a high number of young dependants, whilst many MEDCs have a growing number
of elderly dependants.
How do pyramids change over time?
· A population pyramid that is very triangular (eg Mozambique in 2000) shows a population with a high
number of young dependants and a low life expectancy.
· A population pyramid that has fairly straight sides (more like a barrel) shows a population with a falling
birth rate and a rising life expectancy.
· Over time, as a country develops, the shape changes from triangular to barrel-like.
· Places with an ageing population and a very low birth rate would have a structure that looks like an
upside-down pyramid.…read more
What is migration?
· Internal migration is when people migrate within the same country or region.
· International migration is when people migrate from one country to another .
· Emigration - when someone leaves a country.
· Immigration - when someone enters a country.
Why do people migrate?
· Economic migration - moving to find work or follow a particular career path.
· Social migration - moving somewhere for a better quality of life or to be closer to family or friends.
· Political migration - moving to escape political persecution or war.
· Environmental causes of migration include natural disasters such as flooding.
· Some people choose to migrate but some are forced to.
Push Factors Pull Factors
Lack of services Higher employment
Lack of safety More wealth
High crime Better services
Crop Failure Good climate
Drought Safer, less crime
Flooding Political stability
Poverty More fertile lands
War Lower risk from natural hazards…read more