1. Human Impact on Ecosystems
Chapter 16

2. Human Population Growth and Natural Resources
Everything that humans use come from the Earth
We are dependent on it.
Earth has a carrying capacity.
It can’t have an infinite number of people because it doesn’t have the resources to sustain that many people.

3. Human Population Growth and Natural Resources
Since technology has advanced the carrying capacity of the Earth has increased.
Things like gas powered agriculture has allowed us to make more food.
Medical advances have increased population growth.
Without technology how many people could Earth support?

4. Human Population Growth and Natural Resources
The majority of our energy use comes from oil and coal.
Oil and coal are made up of dead organisms that over millions of years formed into concentrated carbon that form into oil and coal.
These are nonrenewable resources because they are used faster than they form.
What do you think will happen if we run out of nonrenewable resources?

5. Human Population Growth and Natural Resources
Resources that can be used up or can replenish themselves over time are renewable resources.
This would be like wind power, solar power, and the use of water for power.

6. Human Population Growth and Natural Resources
The water we drink is considered renewable, but pollution and overuse are threatening its supply.
Groundwater in aquifers is being removed faster than it can be replaced.
As the population gets larger the management of Earth’s resources will become very important.
Example: Easter Island

7. Human Population Growth and Natural Resources
The amount of land needed to produce and maintain enough food, water, shelter, energy and waste is called an ecological footprint.
Each country has a different size ecological footprint.
Waste management will start to become important as well.

8. Air Quality
Each year humans add synthetic chemicals and materials to the Earth.
This is what we call pollution.
Pollution is described as any undesirable factor, or pollutant, that is added to the air, water, or soil.
Most common air pollution comes from burning fossil fuels.

9. Air Quality
Smog is a type of air pollution caused by the interaction of sunlight with pollutants produced by fossil fuel emissions.
A component of smog is particulate matter and ground-level ozone.
Particulates are microscopic bits of dust, metal, and unburned fuel, 1-10 microns in size, that are produced by many different industrial processes.
NO2 + O2  NO + O3

10. Air Quality
Acid Rain is a type of precipitation produced when pollutants in the water cycle cause rain pH to drop below normal levels.
Acid rain can reduce the pH in lakes and streams causing a decline in growth rates.
It can also make leaves and bark breakdown faster leaving the trees vulnerable to weather or disease.

11. Air Quality The levels of CO2 rise and fall.
CO2 helps keep the temperature of the biosphere in a range that is sustainable to life.
High levels of CO2 correlate with a rise in overall temperature.
Earth’s atmosphere has gases called greenhouse gases that slow the loss of heat through the atmosphere.
Water vapor, CO2, and methane are the most common.

12. Air Quality
The greenhouse effect happens when CO2, water, and methane molecules absorb energy reradiated by Earth’s surface and slow the release of this energy from the atmosphere.
The trend of increasing global temperature is known as global warming.
It’s threatening ecosystems all around the world.

13. Air Quality

14. Water Quality What are some things that can pollute water?
Pollutants can lead to overgrowth of algae and plants.
This lowers the amount of dissolved oxygen which will cause fish to die. It also keeps detritivores from breaking down waste.
This leads to eutrophication.

15. Water Quality
One way we can see how healthy an ecosystem is, is by studying the natural indicator species.
Indicator species aka bioindicator is a species that provides a sign, or indication, of the quality of the ecosystem’s environmental conditions.
Ex: Frogs and Forster’s Tern

16. Water Quality Water soluble pollutants vs fat soluble pollutants
Biomagnification: a pollutant moves up the food chain as predators eat prey, accumulating in higher concentrations in the bodies of predators.
Pollutants are measured in parts per million (ppm)

17. Water Quality

18. Water Quality
Biomagnification has the greatest effect on the animals at the top of the food chain.
Studies on Beluga whales have shown such high levels of toxins that they were considered hazardous waste.
Humans can also be affected.

19. Threats to Biodiversity
Humans have a major impact on biodiversity.
We are threatening animal and plant populations.
Many medical and technological advancements have come from nature.
Loss of biodiversity can make an ecosystem unstable.
Once something is extinct it’s gone forever.

20. Threats to Biodiversity
The best way to protect a species is through conservation.
Development has caused habitat loss.
Habitat fragmentation: when a barrier forms that prevents an organism from accessing its entire home range.

21. Threats to Biodiversity
Introduced species: any organism that was brought to an ecosystem as the result of human actions.
They can cause harm to ecosystems.
Ex: Pythons in the Everglades
Plants can be just as harmful.
Can cause economic damage.
Ex: Mice in Australia

22. Conservation
Sustainable development is a practice in which natural resources are used and managed in a way that meets current needs without hurting future generations.
Lumber industries now use selective cutting practices instead of clear-cutting.
Overfishing is becoming a problem.

23. Conservation Techniques that can be adopted by fisheries:
Rotation of different species
Fishing gear review
Harvest reduction
Fishing bans
Conservation for one species can protect the entire habitat.

24. Conservation
Endangered Species Act is designed to protect individual species that are near extinction by establishing protection for the organism and its environment.
Umbrella species is a species that when its protected a wide range of other animals will be protected.
Many factors are taken into account when trying to protect a species.

25. Conservation
If we were to put a number on the total value of the services Earth’s natural ecosystems provide it would be over $ 30 trillion.
Laws developed by the Environmental Protection Agency have helped restore some of our environment.
National Parks help support and protect wildlife.

26. Conservation We have the greatest impact on the Earth.
We are the only species that can control population growth.
We have the technology to produce more food and produce less waste.
We have the ability to change our practices and TAKE ACTION.