1. Humans in the Biosphere

2. What human activities have changed the Biosphere?
Hunting/Gathering

3. Hunting and Gathering Primary means of survival
Hunted birds, fish, sometimes game
Gathered wild seeds, nuts, fruits
Subsistence hunting: little impact on the environment

4. What human activities have changed the Biosphere?
Hypothesis: arrival of human hunters caused extinction of large animals in North America (approx 10,000 BC)
Wooly mammoths, giant ground sloths, saber tooth felines
Modern subsistence hunters usually use either guns or manufactured tools

5. Agriculture Began approx 9,000 BC
Seeds planted (for food and medicinal use) near settlements
Provided dependable food supply
Caused creation of villages, town, cities
Led to government, laws, “civilization”

6. Domestication of Animals
Farming more reliable
Led to keeping small herds of animals
Sheep, pigs, cows, goats, horses, dogs
Milk, meat, hides, wool, energy (to perform work), companionship

7. Traditional  Modern Agriculture
500 years ago: world travel led to variety of foods/farming
1800s: irrigation, invention of farm machines allowed advances in plowing, planting, harvesting
Greatly increased crop yields

8. 1950s Human population straining world food supply
“Green Revolution” begins
Global effort to increase production of food

9. Green Revolution Global food production has doubled Bad news?
Intensive farming can deplete water supplies & E
Impacted natural food webs
Fertilizer run off interference
Provided food source for certain pests
Led to increase in pesticide use

10. Industrial Growth & Urban Development
Industrial Revolution: 1800s
Led to urban/suburban sprawl
Machinery, factories, transportation
Deposition of wastes (air, water, soil) concerns

11. Resources Renewable & Nonrenewable
Tragedy of the Commons

14. Tragedy of the Commons
Air, water, ocean, land

15. Renewable Resource Can regenerate (replaceable)
Not necessarily limitless (e.g.: water dt drought, overuse)

16. Renewable Resource Single tree vs. deforestation
How does this affect local ecosystem?

17. Sustainable Use
Does not negatively affect supply or quality of future resources
Based on principles of ecology (with consideration to economic impact)
Land, Forests, Air, Ocean, Water
Example: Lady Bugs vs. Pesticides

18. Land Resources
Topsoil: should be “renewable” (nutrient rich, low in salts, excess water drains)
Plowing increases rate of soil erosion (wearing away of topsoil by wind/water)
Farming, overgrazing, drought increases erosion
Can lead to “desertification”

19. Forest Resources Important for products & ecological functions
Lumber, paper, fuel for cooking/heating
Photosynthesis, habitats, limit erosion
Temperate forests considered renewable
Old growth forests (ex: Pacific NW, Alaska) considered non-renewable
Deforestation:
Severe erosion
Permanent changes in local soil/microclimate

20. Sustainable Use
Tree farming

21. Ocean Resources Food source (finfish & shellfish)
Overfishing can destroy populations
Tragedy of the Commons (halibut, cod, salmon, Alaskan king crab all overfished)

22. Air Resources
Cities
smog (usually dt auto exhaust & industrial emissions)
Contains pollutants (any harmful material in land, air, water

23. Burning fossil fuels increases pollutants
Often contain N & S compounds
Form nitric acid & sulfuric acid
Acid Rain

24. Effects of Acid Rain

26. Water Resources Supply of fresh water is limited
Drinking, washing, agriculture, manufacturing
Conservation
Pollution threatens water supplies
Chemicals
Wastes

27. Algal Bloom
Limiting nutrient: when an ecosystem is ltd by a single scarce substance (or one that cycles very slowly)
Fertilizers often used (boosts productivity)
N, P, K
When an aquatic ecosystem receives sudden boost of limiting nutrientan almost immediate increase in amt of algae & other producers (run off, temp changes)
Can deplete O supplies, release toxins, grossly upset aquatic ecosystems
Can occur in fresh or marine water

28. Algal Bloom
If not enough heterotrophs exist to consume algae, ecosystems can become very unbalanced

29. Red Tide

30. Nonrenewable Resource
Cannot be replenished
Supply is finite
Fossil Fuels
Coal
Oil
Natural Gas