The human population has experienced a sharp increase in recent history, growing from relatively few humans to over 6.7 billion people currently due to improved healthcare, clean water, and technological advancements. While the Earth has limited resources and a carrying capacity for how many humans it can support long-term, the growing population risks exceeding these limits and depleting resources if expansion continues unchecked. Individual daily activities like showering and transportation require significant resources on a global scale, demonstrating why conserving resources even on a personal level can benefit the planet.

1. Chapter 20 Lesson 1
P718-722
PEOPLE AND THEIR
ENVIRONMENTS

2. Population and Carrying
Capacity
 For scientist, a population is all the members
of a species living in a given area.
 You are a population of humans! (hurray)
 There are also birds and trees that make up
separate populations in your area.

3. The Human Population
 Earth was once home to relatively few humans
 Today, about 6.7 billion people live on Earth.
The greatest increase in human population
occurred during the last few centuries

4. Population Trends
 A sudden rise in human population that has
happened in recent history is called a population
explosion.
 Look at the chart

6. What caused this sharp increase?
• Improved health care
• Clean water
• Technological advancements
* In 1 hour about 15000 babies
will be born

7. Population Limits
 All living things have certain needs.
 What do humans need?
Food, clothing, clean water, shelter
 Where do all the materials we use for products
come from?
Nature!
 Does Earth have enough resources to support
an unlimited number of humans?

8. Population Limits
 Earth has limited resources
 It cannot support a population of any species
in a given environment beyond its carrying
capacity
 Carrying capacity is the largest number of
individuals of a given species that earth’s
resources can support and maintain for a long
time.
 If the human population continues to grow
beyond Earth’s carrying capacity, eventually
Earth’s resources will run out.

9. Impact of Daily Actions
 As of 2012, the human population is 7.046
billion
Everyone is using resources
Think, everyday people should be drinking 2-3
liters of liquids a day
That’s 14,000,000,000L of liquid consumed in a
day used just for drinking (if everyone got the
necessary amount)

10. Consuming Resources
 Like most people, I hope you are taking a shower
everyday. What resources are needed to make that
happen?
The metals in the pipes are obtained through mining, which
causes pollution and destroys habitats
Gasoline is needed to transport those metals, which
releases pollution into the atmosphere
You probably use a cotton towel. Fertilizers often used to
grow crops run off into water and affect overall water
quality
 Think about all the activities you do in a week and the
resources needed to make them possible. Then,
multiply that by 7 billion.
This why using resources wisely, even at a personal level,
can help Earth

11. Positive and Negative Impacts
 Not all human activities have a negative
impact on the environment.
 What are some positive and negative impacts
of humans?

13. Check Out GapMinder
 Gapminder.org
Food Supply (Y-axis)
Population (x)
GDP (size)