1. Humans in the Biosphere
How have human activities shaped local and global ecology?

2. The Effect of Human Activity
Agriculture
Benefit: food production
Environmental cost: impact on fresh water and fertile soil

3. The Effect of Human Activity
2. Development
Benefit: higher standard of living
Environmental cost: production of lots of wastes

4. The Effect of Human Activity
3. Industrial growth - Benefit: conveniences of modern life - Environmental cost: requires lots of energy to produce and power products.

5. Question:
How might more productive agricultural practices affect a developing nation’s population?
Its environmental health?

6. Sustainable Development
Renewable resources: resources that can be produced or replaced by a healthy ecosystem
Ex. Plants, trees, sun…
Nonrenewable resources: resources that can not be replaced within a reasonable amount of time.
Ex: fossil fuels( coal, oil, natural gas), water

7. Sustainable development
Providing for human needs while preserving the ecosystem that produce natural resources.
Causes no long-term harm to the soil, water and climate
Consume little energy and material as possible
Flexible to survive environmental stresses

8. Using Resources Wisely
3 major environmental concerns:
Soil erosion
Water pollution
Air pollution

9. Soil Healthy soil supports both agriculture and forestry
Topsoil – contains nutrients and minerals essential to growth
Can be a renewable resource if managed properly
Soil erosion – removal of soil by water and wind (over farming, over grazing…)

10. Soil erosion
Desertification – turning farmland into dessert by over farming, over grazing, seasonal drought and climate change
Deforestation – loss of forests, trees hold soil in place

12. Soil Use and Sustainability
Leave stems and roots in ground
Crop rotation
Altering the shape of the land- contour farming

13. Freshwater Resources
Freshwater is usually a renewable resource but if not removed faster than can be replaced: nonrenewable
Aquifer: underground water reserve

14. Water pollution
Harmful materials that enter the biosphere and water source
Point source pollution: from single source like an oil spill
Nonpoint sources – pollution from smaller sources, such as oil and grease off streets
Primary pollution sources
Agricultural chemicals, residential sewage and nonpoint sources

15. Water quality and sustainability
Watershed conservation – clean up pollution
Sewage treatment
IPM – integrated pest management, instead of pesticides (ladybugs)
Conserving water – drip irrigation

16. Biological Magnification
Pollutant is picked up by an organism and not broken down but collects in body tissues.
As food eats food, the pollutant concentration increases ten fold.
At highest trophic levels, concentrations may reach 10 million times their concentration.
Ex. DDT, bold eagles, mercury, pregnant women

18. Acid Rain
Steps:
Coal –burning power plants put smoke high into the atmosphere
The smoke contains high levels of sulfur
The smokestacks were to dissipate the smoke, backfired
Smoke combines with water vapor =sulfuric acid
Acidified precipitation = ACID RAIN

19. Acid Rain

20. Effects of Acid Rain
Most prominent in the Northeastern United States and Southeastern Canada
Why…
pH scale, below 7 = Acid
Under 5, results in damage to organisms, statues…

21. Effects of Acid Rain

22. Ozone Layer O3, protective shield in upper atmosphere
Layer is thinning and disappearing
Allows more UV rays into environment
Why is this an issue?

23. Destruction of Ozone CFC’s – Chlorofluorocarbons
Heat exchanger, refrigerator coolant, aerosol propellant, foaming agents
UV rays are strong enough to break the bonds in CFC’s, releasing chlorine atoms, which in turn react with ozone, destroying it
Limit or ban use of CFC’s
US – limit CFC’s in aerosol’s

24. Ozone Depletion CFCs escape into amosphere CFCs destroy ozone
More UV radiation reaches Earth’s surface
Skin cancer cases increase

25. Good and Bad Ozone Good Bad (forms when sun and emissions react)
Protective layer, absorbs UV rays
Between 11 – 16 miles above sea level
Bad (forms when sun and emissions react)
Corrosive, reactive gas
Pollutant at surface levels
Irritates and damages lungs and eyes, suppresses immune system