1. Population Geography

2. Terms to Know BR(birth rate) DR(death rate)
# of births/1000 in population
DR(death rate)
# of deaths/1000 in population
RNI(rate of natural increase)
(BR-DR)÷10
IMR(infant mortality rate)
# of infant deaths/1000 live births
TFR(total fertility rate)
avg. # of children born to a woman of childbearing age given her country’s BR and DR
Exponential Growth Website

3. Demographic Transition Model
It  is based on an interpretation begun in 1929 by the American demographer Warren Thompson, of the observed changes, or transitions, in birth and death rates in industrialized societies over the past two hundred years or so.

4. Demographic Transition Model
It is an idealized, composite picture of population change in these countries. The model is a generalization that applies to these countries as a group and may not accurately describe all individual cases. Whether or not it applies to less developed societies today remains to be seen.

6. Stage One
Both high birth rates and death rates fluctuate in the first stage of the population model giving a small population
little access to birth control
many children die in infancy (high infant mortality) so parents tend to have more children to compensate in the hopes that more will live
children are needed to work on the land to grow food for the family
children are regarded as a sign of virility in some cultures
religious beliefs (e.g. Roman Catholics and Hindus) encourage large families
high death rates, especially among children because of disease, famine, poor diet, poor hygiene, little medical science.

7. Stage Two
Birth rates remain high, but death rates fall rapidly causing high population growth.
improvements in medical care - hospitals, medicines, etc.
improvements in sanitation and water supply
quality and quantity of food produced rises
transport and communications improve the movements of food and medical supplies
decrease in infant mortality.

8. Stage Three
Birth rates now fall rapidly while death rates continue to fall. The total population begins to peak and the population increase slows to a constant.
increased access to contraception
lower infant mortality rate means there is less need to have a bigger family
industrialization and mechanization means fewer laborers are required
the desire for material possessions takes over the desire for large families as wealth increases
equality for women means that they are able to follow a career path rather than feeling obligated to have a family

9. Stage Four
Both birth rates and death rates remain low, fluctuating with 'baby booms' and epidemics of illnesses and disease. This results in a steady population.
most preventable deaths are avoided

10. Stage Five???
Total population is declining because birth rates have dropped below death rates.
Not originally part of the model, but many post-industrial countries find themselves in this position.

11. Population Pyramids
Useful tool for understanding the structure and composition of populations because they graphically portray many aspects of a country, such as sex ratios and age structures
Can give insights into trends in populations over time by their portrayal of the relative number of people in a cohort (example “baby boom”)

12. DEMOGRAPHIC TRANSITION STAGES
STAGE 1 – Expanding
STAGE 2 – Expanding

13. DEMOGRAPHIC TRANSITION STAGES
STAGE 3 – Stationary
STAGE 4 - Contracting

14. Baby Boom in USA

15. Constrictive Pyramid Has fewer people in the younger age categories
Has been typical of the US population as baby boom populations shift more to conservative birth rates

16. Constrictive Pyramid – USA 2004

17. Expansive Pyramid
Greater numbers of people in the younger age categories
Typical of many developing countries where birth rates are high, but conditions are harsh and life expectancy is short

18. Expansive Pyramid – Sudan 2004

19. Stationary Pyramid
Shows roughly equal numbers of people in all age categories, with a tapering towards the older age categories
Countries such as Iceland, show stationary age categories because of relatively low, constant birth rates and high quality of life

20. Stationary Pyramid – Iceland 2004

21. Review If the Earth’s population = 100 people
The Demographic Transition
Singapore