1. Human Impact on the Environment
For most of history we were hunters & gatherers
- 11,000 years ago we began practicing agriculture, farming

2. Currently:
We practice monoculture= big crops.
This requires the control and use of dangerous chemicals – Pesticides
Industrial growth and urban development= puts a strain on resources and ecosystems.
What does that mean for the future? - Food supply is going to be the a population limiting factor. - Ecosystems will not be able to sustain life.

3. Bioaccumulation
When a pollutant is introduced into a food chain and moves up through the trophic levels, becoming the most concentrated in the tertiary (3rd level) consumers
Example: DDT(pesticide) was used in farming until we realized it was killing large birds (Eagles, pelicans) because their egg shells were so fragile that no new babies were born!

4. Acid Rain
When nitrogen and sulfur compounds from the burning of fossil fuels mix with water to form acids
Can kill plants, dissolve and release toxic chemicals and make water more acidic

5. Habitat Destruction Destroying habitats of plants and animals.
Can be caused by many things- especially human activities.
Can lead to a reduced carrying capacity of the environment and eventually extinction.

6. Deforestation
- Destruction or loss of forests - Can cause erosion, loss of nutrients, loss of habitats, decrease in the number of species (biodiversity)

7. Invasive (non-native) species
Species that are introduced to new habitats where they have no natural predators or parasites that control the population growth,
so they grow exponentially
A dangerous threat to biodiversity
Examples: Kudzu in the Southern US, zebra mussels in San Francisco, CA

8. Climate Change
Global Warming: an increase in the average temperature on the planet
could cause flooding
threats to distribution of species and foods
extinction of animals
weather pattern changes

9. Greenhouse Effect:
natural situation where heat and radiation is trapped by carbon dioxide, methane, water vapor, and other gases.

10. Ozone layer depletion Ozone depletion:
Ozone layer protects the Earth from UV radiation from the sun.
lets more radiation (UV) rays through
Causes skin lesions and cancer
Caused by CFC’s (Chloroflourocarbons)