Population

Key Issue 4

‘J’ and ‘S’ Curves in demography

Why are women having fewer children in MDCs?:

• 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 Pyramidsa.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 baseLow fertility and mortality = narrow base

A better look at rapid, slow and negative growth diagrams

                                 

                                                           

Slide 9 of 34

Developed vs Developinghttp://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 – 1946http://www.ageworks.com/course_demo/200/module2/images/germany46.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

• 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=F-QA2rkpBSY – the mathematics of population, doubling time, percentages and growth

Demographic MomentumHans Rosling

• Demographic Momentum – last 5 min. http://www.gapminder.org/videos/religions-and-babies/