1. THE HUMAN IMPACT ON ECOSYSTEMS Pollution and Overpopulation can seriously damage the health of an ecosystem (the living and non-living factors in an area).

2. As the human population increases, the toll it takes on the Earth increases Pollution – anything potentially harmful that humans add to the environment ex) vehicle exhaust, pesticides, CFCs, sulfuric acid, carcinogens Carcinogens – substance that causes cancer. ex) benzene, dioxin, mercury

3. Pollution Endangers Our Water Supply  When substances like mercury and pesticides (herbicides, insecticides) enter a river, etc. from factory waste, the entire food web can be destroyed.  Negative health effects can also occur

4. Mercury (Hg)  Mercury is a toxic metal that remains in bodies for long periods of time.  Mercury builds up in animals and causes nerve and kidney damage.  The larger the animal, the greater the accumulation of toxic substances. This is biomagnification.

5. Acid Rain pH of ‘Normal Rain’?~5.6

6. Acid Rain  Acid rain is formed when nitric and sulfuric acid is released into the atmosphere from coal-burning power plants.  An increase in the acidity of an ecosystem causes many organisms to die. Ecosystems downwind from factories have the most acid rain.  pH of Normal Rain is 5.6 (slightly acidic). Acid Rain would have a pH less than that  Problems from acid rain:  Kills Plantlife  Pollutes rivers and streams (kills fish)  Erodes statues/stonework

7. THE GREENHOUSE EFFECT U.V I.R. ? ? CO 2 Methane Water Vapor Greenhouse gases? ?

8. Greenhouse Effect  We NEED the Greenhouse Effect (helps to keep us warm). The Troposphere is OUR Greenhouse  Major Greenhouse Gases: Carbon Dioxide, Methane, Water Vapor  Energy from the SUN reaches us as Ultraviolet (UV) light, strikes the earth, leaves behind some ENERGY, and tries to leave the troposphere as Infra Red (IR) ray.  If an IR ray strikes a Greenhouse gas, it will bounce back down to Earth.  TOO MANY Greenhouse Gases, TOO MUCH infra red stays in the troposhpere- the temperature increases!!  Enhanced (Increased) Greenhouse Effect from: Burning fossil fuels, Deforestation (Increase CO 2 )

9. Global Warming 1. Enhanced Greenhouse Effect  When fossil fuels are burned to make energy, they release CO2 and other harmful substances into the atmosphere.  High levels of CO2 have been linked to increasing temperatures on Earth (Greenhouse Effect)  Increasing temperatures on Earth will lead to climate changes (Global Warming)

10. 2. Destroying the Ozone Layer  The ozone layer is a part of our atmosphere (outer edge of the stratosphere) that protects us from carcinogenic (cancer causing) UV rays from the sun.  Chloroflourocarbons ( CFCs ) – found in aerosol can products, coolants, styrofoam  CFCs attack and destroy ozone, create holes in the ozone layer  Most countries have banned CFCs

11. Finding Enough Energy  Fossil fuels are linked to greenhouse emissions and global warming  Fossil fuels are non-renewable (do not replenish themselves fast enough to replace what we use)  Renewable resources can replenish themselves naturally and are being looked at as an alternative to fossil fuels

12. Renewable Resources  Resources that have unlimited supply.  Often considered “green”  Often do not release harmful pollutants and/or carbon dioxide  Examples:  Wind, solar, geothermal, hydroelectric (water) *NUCLEAR POWER- an alternative to fossil fuels but not truly ‘renewable’ ……why? Alternatives to Fossil Fuels