Migration and fertility rates can impact a population pyramid's shape over time. Large numbers of young adult migrants seeking work can make the pyramid broader at those ages. Lower fertility leads to shrinking youth cohorts. As countries develop, their pyramids transition from triangular to barrel shapes with more balanced age distributions. Japan's aging population will continue shrinking as deaths exceed births. Meanwhile, India's youthful population will experience rapid growth, transitioning to a broader pyramid by 2050.

1. READING AGE-SEX
PYRAMID
AFFECTED BY
ASSOCIATED FACTOR

2. MIGRATION AND AGE-SEX COMPOSITION
 Quite often people
who migrate are
looking for
employment
 Great majority of
movers will be young
adults
 The pyramid shows
the effect that a
massive influx of
labour migrants

3. (C) Francesco Scudellari-Comenius
Assistantship 2010/11
Male Female
Population in thousands
This country has a large
number of temporary
workers. These are people
who migrate here especially
to find a job.

4. e.g. of male labour
influx:
2000: Qatar
2005: Dubai,
e.g of female
labour influx:
2000: USA (from
The Philippines)

5. FERTILITY AND AGE-SEX COMPOSITION
 On
average, between
103 and 107 boys
are born for every
100 girls
 As a result, males
outnumbered
females

6.  Decrease in the overall fertility will reduce the
size of the younger cohorts of the population
 Baby booms are created when large
proportions of the women in a population have
children in the same years, typically due to
some critical event (e.g. end of a war)

7.  For
example, the
shape of the
population
pyramid of USA
in 2000
especially at
ages 34-
54, reflects in
part, the effects
of the post-
World War II

8. MORTALITY AND AGE-SEX COMPOSITION
 Male tend to die at higher rates at all ages than
females
 Most changes in mortality experienced by a
population typically affect people in certain age-sex
group
 E.g:
 A reduction in deaths from infectious and parasitic
diseases typically affect younger people the most
 Conversely, reduction in deaths from chronic and
degenerative diseases tends to affect older people

9.  The pyramid of
Sudan in 1990
 The AIDS pandemic
is already having
marked effects on
some young adults
population

10. THE PROBLEMS CAUSED BY HIGH DEPENDENCY RATIOS
 Youthful populations of many LEDCs:
 Government needs to spend more money on education
and healthcare. However, LEDCs are unlikely to have
sufficient money to spend, therefore education levels of
women remain low and will continue to have large
families
 More young women are reaching child bearing age so
natural increase will continue to be high
 Overpopulation – not enough resources to support the
youthful population

11. THE PROBLEMS CAUSED BY HIGH DEPENDENCY RATIOS
 Ageing population in MEDCs:
 Limited manpower for defense of a country
 Give pressure to government to provide more
medical and health facility for ageing population
 Shortage of labour, most of elderly retire and not
enough young people to replace them
 Need more housing facilities and transport to meet
the need of ageing population

12. HOW MAY PYRAMID CHANGE OVER TIME?

13. Over time, as a country develops, the shape of its
population pyramid changes from a triangular
shape to a barrel-like shape with straighter edges.

14. (C) Francesco Scudellari-Comenius
Assistantship 2010/11
POPULATION PYRAMID OF JAPAN in the year 2000
What happens next?

15. (C) Francesco Scudellari-Comenius
Assistantship 2010/11
POPULATION PYRAMID OF JAPAN in the year 2025

16. (C) Francesco Scudellari-Comenius
Assistantship 2010/11
POPULATION PYRAMID OF JAPAN in the year 2050
What is going to happen to Japan’s population in the future?
Why does this matter?

17. (C) Francesco Scudellari-Comenius
Assistantship 2010/11
POPULATION PYRAMID OF INDIA in the year 2000
What happens next?

18. (C) Francesco Scudellari-Comenius
Assistantship 2010/11
POPULATION PYRAMID OF INDIA in the year 2025

19. (C) Francesco Scudellari-Comenius
Assistantship 2010/11
POPULATION PYRAMID OF INDIA in the year 2050

26. BRUNEI
1990 2000 2010
2020 2050