Population
Key Issue 4
‘J’ and ‘S’ Curves in demography
Why are women having fewer children
in MDCs?:
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Later marriage
Delaying childbirth (these two are different)
Higher cost of raising children
Urbanization
Status of women
Higher education levels
Higher economic status
Germany Statistic – In 2008, 39% of German
women had reached the age of 40 without having
had a child
Population Pyramids
a.k.a.
• Population Diagrams
• Population Structures
• Age-Sex Diagrams
• Age-Sex Structures
• Age-Sex Pyramids
Population Pyramids
• A country’s stage of the demographic
transition gives it a distinctive population
structure.
• Pyramids are bar graphs that display a
country’s population in terms of age and
gender.
• Pyramids explain age distribution and sex
ratios.
Features of an age-sex diagram or population
pyramid
•Population is divided
into 5 year age
groups or cohorts
•Population is divided
into males (left) and
females (right)
•The percentage of
each age/sex group is
given
Rapid, Slow and Zero Growth
http://www.bio.georgiasouthern.edu/bio-home/harvey/lect/images/agestructure.gif
High fertility and mortality = broad base
Low fertility and mortality = narrow base
A better look at rapid, slow and
negative growth diagrams
Slide 9 of 34
Developed vs Developing
http://www.zo.utexas.edu/faculty/sjasper/images/3509b.jpg
Can you see the Demographic
Transition here?
http://www.scotland.gov.uk/Resource/Img/53814/0009130.gif
Germany – 1946
http://www.ageworks.com/course_demo/200/module2/images/germany4
6.gif
“Born in East LA”
www.ageworks.com/.../200/module2/module2b.htm
Marina Del Ray – Who are they?
What would be a good business to open
in La Canada?
“Hills that is….Beverly Hills”
What does a ‘Baby Boom’ look like over time?
http://www.nd.edu/~dmyers/courses/old/102au00/bb.jpg
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East Los Angeles is an area with a relatively low level of education and income and a large number of
immigrants from Central and South America. Immigrants tend to be in their 20s. People who are in their 20s are most
likely to have children and immigrants tend to have a slightly larger number of children than those who are native
born. East Los Angeles has a very young population. This neighborhood would have a high need for child daycare
services.
Everyone knows that 90210 - Beverly Hills - is an area where wealthy people live. Beverly Hills is an estabished
suburb of Los Angeles, which developed many decades ago. This population may have relatively fewer children,
smaller families, and they are much older than people in East Los Angeles. This area requires many senior services.
The 20 somethings live in Marina Del Rey or "The Marina" as it is called in L.A. This is an area of apartments
and condos, bars and restaurants, and a single life-style. There are very few people who are either very young or very
old in the Marina. This is more likely to be a place where the television version of the "90210" group lives. If you
wanted to start a dating service, Marina Del Rey would provide a population likely to use this service.
La Canada is a growing suburb on the fringe of Los Angeles. It has expensive homes and good public schools. It
attracts families who can afford such homes; thus, its population is concentrated in the older middle ages. These
families have children who are high-school age or younger. La Canada might be a good place to locate if you were an
orthodontist.
Population Pyramids
• Dependency ratio – the number of people who
are too young or too old to work, compared to
the number of people in their productive years.
Why would geographers study this?
• Sex ratio – number of males per hundred
females.
Why would geographers study this?
Malthus continued
• Pretend you are Thomas Malthus in 1798. What did he see
as he looked out his London window in 1798?
• LINEAR (arithmetic) GROWTH – agriculture increases in a
uniform amount during equal time periods (money
example)
• EXPONENTIAL (geometric) GROWTH – population increases
are compounded on top of one another
• Population and Subsistence - Population would eventually
overtake means to produce food
• Why was Malthus wrong? He probably wasn’t until…
• Green Revolution – Mechanization and Hybridization
• Technology – Genetic engineering
The arithmetic of doubling time and
demographic momentum
• The most important video you will ever see
(according to YouTube)
• http://www.youtube.com/watch?v=FQA2rkpBSY – the mathematics of population,
doubling time, percentages and growth
Demographic Momentum
Hans Rosling
• Demographic Momentum – last 5 min.
http://www.gapminder.org/videos/religion
s-and-babies/