1. Human Populations

2. Demography Demography is the study of populations
especialy refers to the human pop.
Demographers look at historical size and make up of populations in different countries to make comparisons and predictions

3. Types of Countries Countries are in one of two categories:
Developed countries- higher incomes, slower pop. Growth, and diverse industrial economics
Developing countries- lower average incomes, simple and agriculture-based economics, and rapid pop. growth

4. Types of Countries Developed countries slow pop growth?
Low infant mortality
Less need for large families
More focus on careers
Women have more freedom

5. Types of Countries Developing countries rapid pop growth?
high infant mortality
greater need for large families
Less freedom for women
Cultural Traditions
Male child preference

6. Human Populations

7. Population Over Time Population grew exponentially during the 1800’s
Food production was up and hygiene improved, this came with the industrial and scientific revolution
Earth most likely cannot continue to support this growth

9. Forecasting Population Size
Demographers use the following characteristics to predict population changes
Age Structure
Survivorship
Fertility Rates
Migration patterns

10. Age Structure
Age structure: the distribution of ages in a specific population at a certain time
Countries with high growth rate have more young people than older people
Countries with slow or no growth rate have an even distribution of ages
Graphed using a population pyramid
A double-sided bar graph

11. Population Pyramid

12. Population Pyramid

13. Population Pyramid

14. Population Pyramid

15. Survivorship
Survivorship: the percentage of members of a group that survive to any given age
Wealthy countries have a type 1 survivorship curve (most people live to be pretty old)
Poor countries have a type 3 survivorship curve (many children die)

16. Survivorship Curves

17. Survivorship Curves

18. Fertility Rates
A fertility rate is the number of births (usually per year) per 1,000 women of childbearing age (usually 15 to 44).
Replacement level is the average number of children each parent must have in order to “replace” themselves. This number is slightly more than 2 because not all children born will survive and reproduce.

19. Fertility Rates

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

21. Four Stages of Demographic Transition
1st - A society is in a preindustrial condition, birth rate and the death rate are both at high levels and the population size is stable.
2nd - A population explosion occurs, death rates decline as hygiene, nutrition, and education improve. But, birth rates remain high, so the population grows very fast.
3rd - Population growth slows because birth rate decreases. As the birth rate becomes close to the death rate, the population size stabilizes.
4th - The birth rate drops below replacement level, so the size of the population begins to decrease.

22. Demographic Transition

23. Women & Fertility
For women increase in education + economic independence = decline in birth rates
They are able to take better care of their children
Higher survival rates so they do not need to have as many children
Contribute to the family by working
Fertility rates
developed countries ~1.6 children
developing countries ~3.6 children