Population Structure (DP IB Geography)
Revision Note
Population Pyramids
The characteristics of a population, the distribution of age, sex, ethnicity, religion etc, is known as the population structure
It is the result of changes in:
Fertility
Mortality
Migration
Two of these characteristics can be shown as an age-sex structure or population pyramid
This is a graphical illustration of the distribution of a given population, grouped by age and gender
It can be used to represent a population of any region, city, country or even the world
As the population grows the shape of the pyramid changes
The population pyramid can be used to identify the following groups:
Young dependents
Old dependents
Economically active (working population)
Dependency ratio
Features of a population pyramid
Population pyramids of places change over time
They show a place’s population structure at one point in time
The shape of the pyramid changes as a country moves through the stages of the demographic transition model
Population pyramids enable governments, nationally and regionally, to assess the needs of the population for services such as healthcare and education
This means the governments can estimate and plan for spending
Examiner Tip
Although an exam question won’t directly ask you to draw a full pyramid, you may be asked to complete one from given data. Get used to annotating the main features, and shape of a population pyramid for any country. This is a useful exam technique, particularly if you are writing about population change in an essay, as it is an effective way of getting lots of points across in a short space of time.
Population pyramid of the USA
HIC countries such as the USA have a column shape
Stage 4 of the demographic transition model
This indicates:
Decreasing birth rate
Increasing life expectancy
Decreasing death rate
Low infant mortality
Larger working age population
Migration
In some countries, migration can lead to an imbalance in the population structure
The UAE has significantly more males than females
In the UAE 29% of the population are males between the ages of 25 and 39 whereas only 10.5% of the population are women between 25-39
This is the result of the migration of males to the UAE to work in the oil, gas and construction industries
Rapid population growth in some areas as a result of migration can lead to:
Increased pressure on services such as healthcare and schools
A shortage of housing
Increased traffic congestion
Increased water and air pollution
Shortage of food
Lack of clean water
UAE population pyramid
Japan's ageing population
Japan's population fell from 128 million in 2007 to 125.8 million in 2020
The fertility rate is 1.36 births per woman which is well below the 2.1 fertility replacement rate
The birth rate is 6.8 per 1000
The death rate is 11.1 per 1000
The death rate has increased from 6 per 1000 in 1979
This is not because healthcare or diets are worse but because there are far more elderly people who are more likely to become ill and die
Japan has the highest life expectancy in the world at 84.36 years
Japan from a pyramid to a column?
By 2085, although the population of Japan will have shrunk overall, the pyramid shows a relatively stable population; one that isn’t growing or shrinking
The bars are about equal in all age groups, but become smaller at the top as people in the older age groups die
Populations with pyramids this shape have just about a replacement fertility and higher life expectancy
Mexico's shrinking population
Mexico has a replacement fertility rate of just 1.8 (a TFR of 2.1 represents replacement level)
The reducing birth rate is due to out migration of young males
The median age in Mexico is 29.8 years
Mexico - from expanding to contracting
From 1960 to 2022 the population of Mexico increased from 37.8 million to 127.5 million people - a growth of 237.6% in 62 years
The country represents 1.6% of the global population
Peak population growth occurred in 1965 at 3.34% and since then it has steadily declined. In 2022 population growth was just 0.63%
Median age has risen from a low of 15.1 years (1970) to 29.8 years (2022)
Life expectancy is 75 years - females 78.4 and males 71.8 years
Death rate decreased from 13 (1960) to 5 (2008) but increased to 7(2019) and further increased to 9.34/1000 in 2021, where it has remained
Infant mortality has declined from 159.6 per 1000 in 1950 to 10.5 per 1000 (2022)
Working age population stands at approximately 67%, however, by 2067 it is estimated it will be less than 60% with an ever increasing elderly population and decreasing young population
Examiner Tip
When interpreting a population pyramid you need to look at four key areas
Young dependents - is the birth rate high or low?
Working population - are there enough people of working age to support the young and old dependents?
Old dependents - is it large or small? If it is large, then life expectancy is high
Male/female split - are there any noticeable differences between the numbers of males and females?
Dependency Ratio
Population structures and pyramids can be divided into three age-group categories, depending on the level of economic activity
Young dependents - from 0-14 years, they rely on their economically active parents to support them
Economically active - from 15-64 years, they are the working population who earn income, pay taxes and contribute to the support of the young and elderly
Elderly dependent - from 65 years onwards, they are no longer economically active and so rely on support from the state and younger family members
The amount that the young and elderly dependent population of a place depends on the economically active population can be measured
This is expressed as the dependency ratio
The higher the percentage of working-age people, the more income is being produced for a country to support those of non-working ages
An ageing population would have a high dependency ratio – as would a population with a very high birth rate
The dependency ratio tends to be:
Due to youthful population structure with many young dependents
In Niger the figure was 105 in 2021
This means for every 100 people of working age, 105 economically inactive young and elderly depend on them
Due to a large elderly dependent sector of the population
In Japan the figure was 57 in 2021
Due to few elderly dependents because previously there was low life expectancy
Also due to small number of young dependents because birth rates are falling
In Mexico the figure was 48 in 2021
Very high in LICs in stage 2 of the demographic transition model
High in advanced HICs in stage 4 and 5 of the demographic transition model
Lower in MICs in stage 3 of the demographic transition model
Examples of the Dependency Ratio
Country | % Young Dependents | % Elderly Dependents | % Economically Active | Dependency Ratio |
---|---|---|---|---|
Argentina | 24.74 | 11.55 | 63.71 | 56.96% |
Czech Republic | 15.00 | 18.01 | 66.99 | 49.27% |
Haiti | 33.28 | 4.18 | 62.54 | 59.89% |
India | 28.09 | 5.95 | 65.96 | 51.60% |
Madagascar | 40.45 | 3.22 | 56.33 | 77.52% |
Russia | 16.68 | 13.61 | 69.71 | 43.45% |
United States | 18.99 | 14.88 | 66.13 | 51.21% |
The dependency ratio describes how much pressure an economy faces in supporting its non-productive population
Dependency ratio limitations
It assumes that people under 15 years and over 65 years (65+) are outside of the labour force
UK has a retirement age of 67 years (and set to increase) and minimum working age and hours
It assumes that everyone aged 15-64 are working
UK has a school leaving age of 18 years
Examiner Tip
Don't worry about remembering population data, as it will have changed by the time of your exam. What is important is to remember the equation and what it shows.
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