1. Chapter 6 – Humans in the Biosphere

2. 6-1 A Changing Landscape
Earth as an island – we need to need to see how models can be used to make predictions about complex systems… Hawaii pg 139
Among human activities that affect the biosphere are
- hunting and gathering – decreases natural species in certain areas; has caused major mass extinctions

3. - agriculture – created dependable food source… villages settled… habitat destruction, introduced species, pest control, irrigation
- industry – machines and factories use fossil fuels (coal, oil, natural gas)
- urban development – discarded wastes… pollution, movement to suburbs… habitat destruction

4. American artist Chris Jordan recreated Seurat’s masterpiece with digital images of 106,000 aluminum cans - the number used in the US every thirty seconds!

6. 6-2 Renewable and nonrenewable resources
Tragedy of the commons – idea that any resource that is free and accessible may eventually be destroyed.
Renewable resource – can regenerate or be replenished by a chemical cycle; trees, water

7. Nonrenewable resources – cannot be replenished by natural processes; fossil fuels burn and energy is given off
*** a population of trees may be nonrenewable if ecosystem changes

8. Sustainable development – use ecological studies to see how we are impacting the environment in order to save resources
Land resources – soil can be permanently damaged
- soil erosion and desertification occur when humans change environment… contour plowing and leaving in roots can help

9. Forest resources – used for materials, oxygen, habitats, and food
- deforestation can lead to erosion and loss of habitats
Fishery resources – oceans and lakes provide a lot of food – aquaculture
- overfishing is an example of the tragedy of the commons

10. Air resources – cities produce smog, a pollutant from the burning of fossil fuels that can cause health problems
-acid rain – nitric and sulfuric acids with a high pH which can kill plants and animals

11. Chemical Transformation Emissions to Atmosphere
Formation of Acid Rain
Chemical Transformation
Nitric acid
Sulfuric acid
Condensation
Emissions to Atmosphere
Nitrogen oxides
Sulfur dioxide
Dry Fallout
Precipitation
Acid rain, fog,
snow, and mist
particulates, gases
Industry
Transportation
Ore smelting
Power generation

12. Freshwater resources – pollution threatens water supplies; improperly discarded chemicals, domestic sewage

13. 6-3 Biodiversity
Biodiversity = the sum total of the genetically based variety of all organisms in the biosphere
- one of Earth’s greatest natural resources.

14. Species of many kinds have provided us with foods, industrial products, and medicines – including painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs.

15. Human activity can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environments.

16. Species Diversity

17. Pollution – DDT, a pesticide, became more concentrated as it moved up the food web… biological magnification

18. Biological Magnification of DDT
Fish-Eating Birds
Magnification of
DDT Concentration
10,000,000
100,000
10,000
1,000,000 1
1000
Large
Fish
Small Fish
Zooplankton
Producers
Water

19. Introduced species – humans transport plants and animals around the world that take over a new habitat

20. Conserving Biodiversity
- managing endangered species, protecting habitats, fishing regulations

21. Sustainable Agriculture
Cover Crops
Legumes, grasses, and other
cover crops recycle soil nutrients,
reduce fertilizer need, and
prevent weed growth.
Controlled Grazing
By managing graze periods and herd
densities, farmers can improve nutrient
cycling, increase the effectiveness of
precipitation, and increase the carrying
capacity of pastures.
Biological Pest Control
The use of predators and parasites
to control destructive insects
minimizes pesticide use as well as
crop damage
Contour Plowing
Contour plowing reduces
soil erosion from land runoff.
On hilly areas, plowing is done
across the hill rather than
straight up and down.
Crop Rotation
Different crops use and
replenish different nutrients.
By rotating crops, the loss
of important plant nutrients
is decreased. A B C
Yr. 1
Yr. 2
Yr. 3
corn
alfalfa
oats
alfalfa (plowed in)

22. 6-4 Charting a Course for the Future
Ozone depletion – ozone layer absorbs harmful ultraviolet radiation; evidence exists that chlorofluorocarbons, CFCs, could damage the ozone layer; use of most CFCs are banned in US
Global Climate Change – increase in the average temperature of the Biosphere; some scientists attribute this to human activities and the burning of fossil fuels… CO2

23. Ecosystem Services Solar energy Production of oxygen
Storage and recycling of
nutrients
Regulation of climate
Purification of water and air
Storage and distribution of
fresh water
Food production
Nursery habits for wildlife
Detoxification of human and
industrial waste
Natural pest and disease
control
Management of soil erosion
and runoff

24. How does everything fit?