Population Age Structure Review

1. Population Age Structure Review • There are 3 basic age structures: • Expansive • Stationary (slow/no growth) • Regressive • Which r-values go with which structures? • CBR = 15, CDR = 10 • CBR = 9, CDR = 10 • CBR = 40, CDR = 20

2. Population Pyramids—which is which? Images adapted from: http://www.health.state.pa.us/hpa/stats/techassist/pyramids.htm

3. Demography Part II-Demographic Transition

4. Demographic Transition • Basically, as countries become more developed/more industrialized, two things happen: • First • The death rates decline • And then • Their birth rates decline

5. There are 4 stages to demographic transition • Pre-industrial • Transitional • Industrial • Post-industrial

6. Stage 1: Pre-industrial • Pre-industrial- high birth, high death—balanced • This is what existed for the bulk of human history with growth rates of less than 0.05% • High death rates caused by: • Lack of clean drinking water • Lack of efficient sewage disposal • Poor food hygiene

7. Stage 2: Transitional • Transitional- Death rates drop, but birth rates remain high • The decline in the death rate is due initially to two factors: • improvements in food supply • significant improvements in public health that reduced mortality, particularly in childhood. Examples?

8. What are differences in the transitional stage between Mexico and Sweden? Figure from: http://www.uwmc.uwc.edu/geography/Demotrans/demtran.htm

9. Figure from: http://www.uwmc.uwc.edu/geography/Demotrans/demtran.htm

10. Stage 3: Industrial • Industrial- Birth rates drop, due to a variety of causes including: • Increasing urbanization • Increasing female literacy and employment • Improvements in contraceptive technology

11. What can you observe on this graph?? Figure from: http://www.uwmc.uwc.edu/geography/Demotrans/demtran.htm

12. What happened to Mexico’s population between 1980 and 1998?? Figure from: http://www.uwmc.uwc.edu/geography/Demotrans/demtran.htm (from: http://www.census.gov/ipc/www/idbpyr.html)

13. Stage 4: Postindustrial • Postindustrial- birth rates drop to equal death, then may decline BELOW death rates • If birth rates go below death rates the population starts… • DECREASING

14. Figure from: http://www.uwmc.uwc.edu/geography/Demotrans/demtran.htm

15. Differences in demographic transition between more and less developed nations • Less developed nations have a: • Later (in history) transition • Faster decline in death rates • Longer time lag between death rate decline and birth rate decline---economic changes are slower to come than they were in more developed nations • Higher maximum growth rates

16. Population Growth through Natural Increase, 1775–2000 Figure from: http://www.prb.org/Content/NavigationMenu/PRB/Educators/Human_Population/Future_Growth/Natural_Increase_and_Future_Growth.htm

17. Brazil Population Pyramid 1990