1. TEST FRIDAY – chapters 14, 25, 26, 27 and biosphere
Warm-up
What is the primary source of energy on Earth?
TEST FRIDAY – chapters 14, 25, 26, 27 and biosphere

2. TEST MONDAY – chapters 14, 25, 26, 27 and biosphere

3. Human Impact on Earth Resources
Chapter 27

4. Population Growth
Exponential growth – runaway expansion of a population
Limiting factors – factors that limit population growth, such as food, water or air
Carrying capacity – number of organisms that the environment can support

5. Carrying Capacity
When the population levels off, organisms die at the same rates that new organisms are born

6. Environmental Limits to Population Growth
Density Independent Factors: impact all populations regardless of population size.
Ex - meteorite impacts, earthquakes, volcanoes, storms, floods, pollution

7. Environmental Limits to Population Growth
Density Dependent Factors: worse as a population size increases or when population members live close together.
Ex. - Diseases, limiting resources (food, shelter), predation, production of toxic wastes

8. Does this show carrying capacity?

9. Land Resources Review
Biodiversity – variety of species of plants and animals
High biodiversity leads to more stable ecosystems

10. Agriculture Traditional (Conventional) Agriculture
Goal to make the most food using the smallest area of land
Large scale

11. Agriculture Monoculture – the planting of one plant species in a field
Benefits – more efficient
Drawbacks– more vulnerable to disease, pests

12. Agriculture Pesticides – kill organisms that harm crops
Benefits – increased food production
Drawbacks –
Can remain in environment and harm other organisms
Insects can develop resistance to insecticide

13. Benefits of Traditional Agriculture
Fruits and vegetables available year-round
Cheap food
High food supply in developed world

14. Drawbacks of Traditional Agriculture
Erosion and soil loss
Water, air pollution
Habitat loss

15. Land Use: Forestry Deforestation – removal of trees without replanting
Clear-cutting – removal of all trees in an area
Can lead to erosion and loss of topsoil

16. Land Use: Forestry Negative impacts can be reduced by:
Selective logging
Buffer zones of trees along streambeds

17. Urban Development Natural habitats lost Increased erosion of topsoil
Land taken away from agricultural use
Concrete/asphalt prevents groundwater recharge
Mexico City

18. Mining
Surface mining happens near the surface

19. Subsurface mining is used for mineral deposits deep under ground

20. Mine Products
Ore- a mineral deposit large enough and pure enough to be mined for profit

21. Reclamation
Reclamation- returning land used for mining to its original state to better

22. Air Pollution
Air Pollution - chemicals, particulates or biological materials that damage the natural environment or harm organisms

23. Air Pollution Ozone layer protects the Earth from UV radiation
CFCs (chlorofluorocarbons) react with ozone, destroying it.
1989, CFCs banned from refrigerators, cleaning agents, and propellants in aerosol cans in developed countries

24. Air Pollution
Acid Rain - precipitation with a pH of less than 5.0 (acidic)
occurs when SO2 (sulfur dioxide) and NOx (nitrogen oxides) combine with atmospheric water vapor to create sulfuric acid (H2SO4) and nitric acid (HNO3)
90% of SO2 from human activity

25. Water Pollution Point sources –single point of origin
Nonpoint sources –pollution from widely spread areas

26. Ocean Acidification
About 30% of CO2 released by humans into the atmosphere dissolves into the oceans, rivers and lakes.
Combines with water to form carbonic acid, increasing the ocean’s acidity

27. Ocean Acidification ↑ CO2 in atmosphere leads to ↑ CO2 in ocean
↑ CO2 in ocean leads to ↑ acidity
↑ acidity leads to ↓ ability of organisms to make calcium carbonate shells

28. Human Impact on Biosphere
Soil – Agricultural practices have exposed topsoil to the weather resulting in great loss
Water Cycle – Deforestation increased uncontrolled runoff leading to increased erosion and flooding
Agricultural Waste – untreated sewage and runoff from farms and feedlots lead to water pollution
Pollution – landfills, septic waste mismanagement, industrial waste, and air pollution