Unit 2B Human Impact on the Biosphere

1. Unit 2B Human Impact on the Biosphere Chapter 6 in the textbook

2. Development 6.1 – A Changing Landscape

3. 6.2 Using Resources Wisely

4. 1. Soil Resources • Soil is needed to grow crops (for food!) • Healthy soil has nutrients, few salts, and can hold moisture while allowing extra water to drain • Healthy soil is created over long periods of time by interactions between soil and the plants growing in it

5. Soil Erosion • The removal of soil by water and wind • Roots of growing plants normally hold soil in place and prevent erosion • If plants are removed, erosion can occur more easily • Also, erosion carries away nutrients that make the soil healthy

6. Desertification • The process of turning farmland into desert that occurs due to farming, overgrazing, drought, and climate change.

7. Deforestation • The loss of forests • Forests hold soil in place and absorb CO2 • Without forests, soil erosion can occur and there will be more CO2 in the atmosphere. • Sometimes forests can grow back, but it can take centuries

8. 2. Atmospheric Resources • We need oxygen from the air to breathe • Ozone (O3) in the upper atmosphere absorbs UV rays, protecting us from skin damage that causes cancer. • Greenhouse gases (carbon dioxide, methane, and water vapor) hold heat in the atmosphere to regulate Earth’s temperature

9. Air Pollution • Burning fossil fuels (coal, oil, natural gas) release pollutants (harmful materials) into the air • This can affect breathing, and change climate

10. Forms of Air Pollution • Smog- - Gray-brown haze formed from chemical reactions between air pollutants - Harmful when breathed in

11. Forms of Air Pollution (cont.) B. Acid Rain- - Two of the elements released into the air by the burning of fossil fuels are nitrogen and sulfur - When combined with water vapor, these become acids, and fall as acid rain (below pH of 5.0) - Can kill plants and change the chemistry of the soil

12. Forms of Air Pollution (cont.) C. Greenhouse gases- - In addition to nitrogen and sulfur, burning fossil fuels also releases carbon into the air as CO2 - Burning forests also release CO2 - CO2 is a greenhouse gas - Excess greenhouse gases cause global warming because they trap heat in the atmosphere

13. Forms of Air Pollution (cont.) D. Particulates- - Microscopic particles of ash and dust released by industries and diesel engines - Can be breathed into the lungs and cause health problems

14. 3. Freshwater Resources • We rely on fresh water for drinking, industry, transportation, energy, and waste disposal • Only 3% of Earth’s water is fresh (most of that is frozen at earth’s poles) • Freshwater ecosystems should be protected

15. Water Pollution • Water pollutants come from factories, oil spills, automobiles, (etc.), or can be washed off the ground by rain. • Most pollutants come from industrial and agricultural chemicals, and residential sewage.

16. Positive Synergy • Occurs when two pollutants have little effect on their own, but multiply each others effect when combined

17. Industrial and Agricultural Chemicals • Rainwater washes waste chemicals, fertilizers and pesticides into the water supply. • Excess fertilizer in the water can lead to eutrophication • When organisms (like primary producers) in the water pick up chemicals, their bodies can’t get rid of them, so they store them in their cells. • When the consumers eat the producers, they eat and store the chemicals too.

18. Biological Magnification • As chemicals stored in organisms travel up the food chain, they become more concentrated in the bodies of the organisms • This process is called biological magnification

19. Biological Magnification (cont.) • The higher the trophic level, the greater the concentration of chemicals • Roughly 10 times greater at each trophic level • This can cause serious problems for wildlife, and even for humans who eat fish

20. 6.3 Biodiversity

21. Biodiversity- • The variety of all forms of life in the biosphere. • Three types: ecosystem diversity, species diversity, and genetic diversity.

22. 3 Types of Biodiversity • Ecosystem Diversity- The variety of habitats, communities, and ecological processes in the biosphere. • Species Diversity- the number of different species in the biosphere • Genetic Diversity- all of the variations in genetic information (genes) carried by the organisms of the biosphere.

23. Threats to Biodiversity • Human activities can alter biodiversity by causing the extinction of certain species. • Altered habitats: changing or removing a habitat to farm or build on the land - Habitat fragmentation- splitting an ecosystem into pieces by developing an area 2. Hunting: killing animals for food, sport, or to sell body parts (like skin, fur, tusks, etc.)

24. 3. Invasive species (also called “introduced” or “exotic”): non-native organisms brought into an ecosystem. 4. Pollution: forms of pollution can affect the ability of new generations to survive. - Pesticides can prevent birds from laying eggs - Acid rain can make water more acidic, affecting the survival of aquatic organisms

25. 5. Climate Change: the increase in global temperature. - species are adapted to survive in a certain temperature range. - it is uncertain how disruptive climate change will be to the biodiversity on Earth.

26. Conserving Biodiversity • Protect Individual Species- placing endangered species into zoos or aquariums where they can safely reproduce. - The goal is to later place the organisms back into the wild.

27. Conserving Biodiversity (cont.) 2. Preserving Habitats and Ecosystems- protect the areas where organisms live. - Ecological Hot Spots- places with large numbers of species and habitats that are in danger of extinction.

28. Conserving Biodiversity (cont.) 3. Incentives to change behavior- - US government offers tax credits to people who put up solar panels or buy hybrid cars - Industries are paid money when they release less pollution

29. 6.4 Meeting Ecological Challenges

30. Renewable Resources • Resources that can be produced or replaced quickly after they have been used. Examples: • Trees- can grow back (relatively) quickly after they have been cut down. • Sun, wind, water, geothermal (all can be used for energy) • Biomass- garbage, wood, waste, plants, landfill gases (all can be reused for energy)

31. Nonrenewable Resources • Resources that can not be replenished within a reasonable amount of time after they have been used. Examples: • Fossil Fuels- coal, oil, natural gas • Take millions of years to form • Once they are used up, they will be gone forever These resources are “finite”!!

32. Ecological Footprint • Refers to the human impact on the environment • Describes the total land and water needed to provide for an individual and make harmless its wastes • Takes into account what is needed to provide energy, food, water, and shelter, and to absorb wastes like sewage and greenhouse gases

33. Comparing Footprints • It is hard to calculate the exact size a footprint for a person, country, or the world • Estimated footprint sizes show that Americans have a footprint 4 times larger than the global average

34. Comparing Footprints

35. Sustainability • The ability to use resources in a responsible way, thinking about the future Examples: • leave stems and roots from crops to prevent erosion • Replant trees • Sewage treatment to protect the water • Plants roots filter water in the ground, so maintain the land that the water runs through • Remove cars that pollute excessively from the road • Remove excess chemicals from gasoline • Use more renewable resources than nonrenewable

36. A Sustainable Future- • Means how to face ecological challenges so that our resources are not gone or unhealthy in the future • How do scientists face ecological challenges? • Recognize the problem • Determine the causes • Show us how to change our behavior to help or fix the problem