1. Section 16.1: Human Population Growth and Natural Resources
Biology

2. Objectives
How is the human population stretching the Earth’s carrying capacity?
How is the growing human population exerting pressure on Earth’s natural resources?
Explain how effective management of Earth’s resources will help meet the needs of the future.

3. Earth’s carrying capacity
Thomas Malthus: 1700s
First proposed that human population was growing faster than Earth’s resources could support
His observations and predictions are still being used today
Today’s human population is about 7 billion people, higher than earlier predictions of what the Earth could hold
Do not know the exact number of people that can be supported, but it is not unlimited, and it changes depending on how we utilize resources

4. Technology and human population
Human modifications has changed the carrying capacity of Earth
Agriculture, transportation, medical advances, and sanitation
Farming
Farming equipment has allowed for vastly more food production than simple human and animals could have ever produced
Medical Advances
Contributed to population growth
Decrease in infant mortality, death from infection prevented by antibiotics and antiseptic cleaners

5. Nonrenewable resources
Nonrenewable resources are resources that are used faster than they form
Oil and coal make up the majority of our energy use
Made from dead organisms that have been concentrated over thousands of years
2006: 77 million barrels per day of oil
This growth cannot continue indefinitely, new technologies need to be developed to use other forms of energy

6. Renewable Resources
Renewable Resources: Resources that cannot be used up or can replenish themselves over time
Wind and Solar Energy cannot be used up by humans
Plant and animal resources are renewable because they could last indefinitely if allowed to regrow and reproduce over time
Need to be replenished faster than they are used
If renewable resources are not used carefully they can become nonrenewable

7. Drinking water Currently drinking water is a renewable resource
Pollution (pesticides, industrial waste, and other contaminants) have been found in water sources
This contaminates water sources for millions of people
Groundwater is also being extracted from aquifers faster than it is being replaced
This is one of the reason’s the drought in California has been going on for so long
Both contamination and overuse can lead to a loss of this renewable resources

8. waste
The United States uses more resources and produces more waste than any other country on Earth
230 million tons of garbage per year
4.2 pounds per day per person (1 ton per person per year)
If we all generated that must trash (everyone on Earth) could our planet sustain our usage and out waste?

9. Easter island First landed in A.D. 400 and 700
Thick forest, rich soil, with many bird species
Human population increased over 1000 years
Forests were cut down for boats and houses
Trees were not replenished and eventually there were no trees left
No trees means no wood for shelter or boats, but also means no habitat for native bird species
No boat = no fishing = no food
Soil washes away

10. Easter Island
Eventually human population crashed and people left Easter Island
Islanders used their renewable resources in a nonrenewable way
This had a long term negative effect on the island and on them

11. Ecological footprint
Earth’s carrying capacity is dependent upon how much land is needed to support each person on Earth
Ecological Footprint: amount of land necessary to produce and maintain enough food and water, shelter, energy, and waste
Size of ecological footprint depends on number of factors
Factors:
Amount of resources
Efficient use of resources
Amount and toxicity of waste produced

14. Ecological Footprint
Many decisions need to be made about the way humans live and use their resources
Waste production and management
Rules to regulate resource use and waste production
How much resource use and waste production should individuals and populations be allowed?
How much land is needed for agriculture, living space, other uses?
How much water for crop irrigation and for humans drinking water?
Humans need to move away from consumerism to sustainability

15. Output
Use the Frayer model to define nonrenewable and renewable resources.
The progressive increase in Earth’s human carrying capacity came from advances in technology. What density-independent and density- dependent limiting factors may prevent the human population from continued growth?