A scientist places one bacteria in a Petri dish at 9:00 am. The bacteria can reproduce at a rate that doubles its population every minute. The scientist observes that the Petri dish is completely full at 10:00 am.

Warm-Up

1. What do you think will happen after 10 am?

2. In what ways is this example similar to human population growth?

3. In what ways is this example different from human population growth?

The Human Population

Exponential growth – a quantity increases by a fixed percentage in a given time

The world’s population is increasing at 1.15% every year

Industrial Revolution

Year

Human Population Growth Over Time

The Rule of 70

The “Rule of 70” is an easy way to estimate how long it will take a population to double, if you know the growth rate

The Rule of 70

Ex: If a population’s growth rate is 7% a year, how long will it take to double in size?

70/7% = 10 years

The Rule of 70

If a country’s population is increasing at about 2% every year, how long will it take to double in size?

70/2% = 35 years

The Rule of 70

Ex: If a population’s growth rate is 5% a year, how long will it take to double in size?

70/5% = 14 years

The Rule of 70

The world’s population is increasing at about 1.15% every year, how long will it take to double in size?

70/1.15% = 61 years

Human Population Density

Human Population Density

Population Map

Wealth Map

Think About It

343,000Amount by which the population of all European Union countries combined grew in the year 2000.

343,000Amount by which India's population grew in the first week of 2001.

If the world were a village of 100 people, there would be:

60 Asians 14 Africans 12 Europeans 8 Central/South Americans & Caribbean 5 North Americans 1 Oceania

If the world were a village of 100 people, there would be:

80 living in substandard housing 50 suffering from malnutrition 33 lacking access to safe drinking water 24 lacking electricity

WORLD POP.

Developed Countries

Developing Countries

U.S., Canada, Australia, NZ, Japan, Europe

Africa, Asia, Latin American, South

America

• > $10,750 per capita GNI

• 19% of world pop.

• 85% of world’s wealth

• Use 88% of resources

• < $10,750 per capita GNI

• 81% of world pop.

• 15% of world’s wealth

• Use 12% of resources

What Do You Think?

Are developed countries, like the U.S., obligated to help developing countries develop? Should we be sending our money to other

countries to help provide them with food, clean drinking water, etc.?

Are we obligated to offer financial assistance to developing countries, like Haiti, who have suffered a natural disaster?

A Changing Population

Based on the differences between developed and developing countries, which do you expect to be increasing in size faster? Developed or developing?

Population Questions

Should we be concerned with the increasing world population size?

What should be done to slow the rate of growth?