1. Forecasting Population Size
Based on Certain Criteria

2. Forecasting Population Size
Based on Certain Criteria :
Age structure - classifies members of a population into groups according to age or the distribution of members of a population in age groups
helps demographers
make predictions

3. high rates of growth = more young people
slow growth or no growth = even distribution of ages

4. Population Pyramid
a graph showing majority of ages of people in the population
predicts if and when the population will grow 4

5. Population Pyramid
Age of population

6. What is the overall shape of the graph?
Is there a dominant age group or groups?
What proportion of the age group survives into the elderly (60+) age groups?
Are the male and female sides roughly equal?

7. Age-Structure Diagrams

8. Activity Reading and analyzing a Population Pyramid Graph.
Textbook: Page 220
Answer the questions pertaining to this graph.

9. Forecasting Population Size continued…
2. Survivorship:
Percentage of newborn individuals in a population that are likely to survive to any given age
Demographers note birth and then the death groups

10. Types of Survivorship Curves
Varies from country to country.
Developed countries have higher survival rates. Why?
Types of Survivorship Curves
Type I - most people live to be very old
Type II - have a similar death rate at all ages
Type III - many offspring die
Both Type I and Type III may result in populations that remain the same size or grow slowly.

11. 3. Fertility Rates: -Number of babies born per year per 1000 women.
-Replacement level is the average number of children each parent must have in order to “replace” themselves.
Change in population = births – deaths

12. Fertility Rates

13. Migration: movement of individuals from one area to another
Immigration: moving into an area
Emigration:
moving out of an area

14. Migration between and within countries is a significant part of population change.

15. Life Expectancy Average number of years a person is expected to live.
Most affected by infant mortality - death rate of children less than 1 yr. old
Affected by parents’ education
food
fuel
clean water
population density
disease

16. Life Expectancy in USA

17. The Demographic Transition
the general pattern of demographic change from high birth and death rates to low birth and death rates
observed historically in more-developed countries
industrial development causes economic and social progress that then affects population growth rates

18. Stages of the Transition

19. Stage 1 - Preindustrial
high level birth rate and the death rate
population size is stable

20. Stage 2 - Transitional
population explosion occurs
death rates decline
hygiene, nutrition, and education improve
birth rates remain high
population grows very fast

21. Stage 3 - Industrial
population growth slows
birth rate decreases
population size stabilizes but larger

22. Stage 4 - Postindustrial
birth rate drops below replacement level
population size decreases

23. Women and Fertility Women who have fewer children are:
Those who know family planning techniques
Independent
Educated

25. Activity Section Review questions page 231
Answer every question in a complete sentence.