1. Unit: Ch. 9
The Human Population

2. How do we study the human population?
Demography – study of human populations
historical size and makeup of populations of countries in order to make comparisons and predictions
Population Size-total number of individuals
Population Density-number of individuals per given unit of area
2 categories for countries
Developed – higher average income, slower birthrate, diverse industrial economies
Developing – lower average income, agriculture-based economies, rapid population growth

3. Human population over time
Grew slowly up until 1800
1800’s – went through exponential growth
Population growth increases every decade
Due to increases in food production, better hygiene, industrial and scientific revolution
Not likely the earth can sustain this growth
Current population size is 7.6 BILLION!!

4. Human population over time

5. Forecasting population size
Age structure – distribution of ages in a pop – shown in a pop pyramid
Survivorship – percent of members of a group that are likely to live to a certain age – shown with line curves
Fertility rates - number of babies born each year per 1,000 women
Replacement level – average of children a parent must have to replace themselves, about 2 because not all babies survive
Migration – movement of individuals between areas
Immigration – entering, into
Emmigration – exiting, leaving

6. Declining death rates
Dramatic increase in population in the last 200 years due to drop in death rates
More access to adequate food, clean water, and safe sewage disposal
Life expectancy – average number of years a member of a population is likely to live
Most affected by infant mortality – death rate of infants under 1 year old
1900: 40 years old world wide with high infant mortality
2000: 67 years old world wide and infant mortality decreased to less than 1/3 of 1900 rate

8. The Demographic Transition
The populations of most developed countries have stopped growing
Model that describes how economic and social changes affect population growth rates (within a country)
Process takes 3 – 4 generations
Stages
1. Preindustrial – birth rate and death rate are high, little change in population size
2. Transitional – population explosion, death rate lowers due to education, hygiene, nutrition, birth rates remain high
3. Industrial – birth rate declines and gets close to the death rate so the population stabilizes
4. Postindustrial – birth rate below replacement level so population decreases

9. Studying Human Populations
Chapter 9

10. Problems of rapid population growth
1. Overwhelming the infrastructure
Infrastructure – basic services and facilities that support a community (water supplies, roads, sewer lines, schools, etc.)
Symptoms:
Suburban sprawl
Overcrowded schools
Polluted rivers
Barren land
Inadequate housing
Poor sanitation

11. Problems of population growth
Resources used faster than they can be replenished or wastes overwhelm water sources
-vegetation, land, and water are the most affected
3. Fuelwood shortage – wood
gathered from fallen limbs to burn
as fuel
- when population rises trees
are cut down for fuel
Fuel allows people to boil water and cook
No fuel leads to malnutrition and disease

12. Problems of population growth
Unsafe water – in cities where there is no infrastructure
local water source may be used for drinking, washing,
bathing and sewage disposal
Water becomes breeding ground for organisms that cause diseases like cholera, typhoid, and dysentery

13. Problems cont. Impacts on land – different uses for land are in
competition with each other (agriculture, housing,
natural habitats)
Arable land – used for growing crops
Urbanization – movement of people from rural areas to cities for work
Suburban sprawl – leads to traffic jams, inadequate infrastructure, and reduction of land for farms and wildlife

14. Demographic diversity in the world
Countries can be developed or developing, more developed or less developed
Least developed countries are identified by United Nations and are given priority for foreign aid and development programs

15. Demographic diversity in the world
Less developed countries suffer more from rapid population growth because they are less likely to have the family planning methods to support the population
Educating women worldwide has lowered birthrates because they may learn family planning techniques

16. Managing Development and population growth
Government focus is on reducing birth rates
Public advertising
Family planning programs
Economic incentives
Tax breaks
Legal punishments
China’s one child policy(70’s)
Now-2 children

17. Growth is slowing Population is now 7 billion and increasing
Fertility rates are declining in both developed and less developed regions
Most countries predicted to have “replacement level” fertility rates by 2050
UN predicts world population to grow to 8.5 billion by 2030, driven by growth in developing countries