1. Population

2. Population Population is the total number of people living in an area.
Population distribution is the way the population is spread out over an area.

3. Demography
Demography is the science that tries to explain how populations change and why population distribution is uneven.
Demographers study rates of birth, marriage, death, and why people move from one place to another.

4. Reasons Why People Move
Better jobs
Not enough food
They are forced to move

5. Population and History
In the past most people lived on farms and grew their own food.
They lived in a climate that had plenty of water and warm weather to support crops.
Regions with a long history of farming, good soil, and plenty of water became crowded.

6. New Population Clusters
After 1800, improved transportation and news ways of making money changed things.

7. New Population Clusters 2
Railroads and steamships made it easier for people to move long distances.
New jobs allowed people to live in cities.
Crowded cities grew in places that once had few people.
Ex: USA and Northern Europe

8. Population Density vs. Population Distribution
Population density is the average number of people per square mile or kilometer.
If you have 50 people living in a 5 square mile area you have 10 people per square mile.
5 square miles /50 people = 10 people per square mile (ppsm)

9. Population Density vs. Population 2
Population distribution is the way the population is spread out over an area.
Massachusetts has a population density of 810 ppsm, but they are not spread evenly throughout the state. Most of those people live in the Boston and Springfield area.

10. Population Density Map
Where are the most populated areas?

11. Population Growth The population has growth quickly in recent times.
For years farmers worked without modern machinery, food supplies were scarce, there was not clean water or waste removal.
Many people died of infectious diseases.
People had a short life expectancy during this time period.

12. Reasons for Population Growth
New farming methods increased the food supply.
New ways to protect crops against insects were created.
New ways to raise crops with less water were created.
These improvements are called the Green Revolution.

13. Reasons for Population Growth 2
Governments began finding ways to provide clean drinking water.
Advances were made in waste removal.
Vaccines were developed to prevent disease.
As a result, people lived much longer.

14. The Challenges of Population Growth
Some people still do not have enough drinking water.
The populations of Asia and Africa are growing faster than the food supply.
Many countries in Asia and Africa do not have enough money to buy food from other countries to feed their people.

15. The Challenges of Population Growth 2
Populations are increasing so fast that not everyone can find jobs.
There are not enough schools to educate the growing number of children.
It’s hard to find a good place to live.
Public services such as transportation and sanitation are not good enough.

16. The Challenges of Population Growth 3
People are using up all of the world’s resources. Forests are disappearing as people cut down trees for firewood and fuel.
Heavy rainfalls will wash away soil in these areas causing heavy flooding.