Ch. 18 The Environment

1. Ch. 18 The Environment By: Brianna Shields March 27, 2006

2. DO NOW • Which cycle requires the nutrient to be released into the soil by dissolving rock? • Which food chain member possesses the greatest amount of available energy? • Which member of a food web is considered to be a primary consumer?

3. GOALS • Recognize the causes and effects of acid rain • Evaluate the long-term consequences of atmospheric ozone depletion • Explain how the burning of fossil fuels has changed the atmosphere • Analyze the proposed relationship between the greenhouse effect and global warming • Describe the effects of chemical pollutants on the environment • Identify three nonrenewable resources • Predict the potential consequences of uncontrolled population growth • Contrast population growth in developing countries with that in industrialized countries • Describe two effective approaches that have been taken to reduce pollution in the United States and abroad. • Evaluate the five major steps necessary to solve environmental problems • Determine how individuals can take personal action to help solve environmental problems

4. Acid Rain Coal burning power plants release sulfur into air Sulfur + Water Vapor = sulfuric acid Acid carried back to Earth by rain and snow The Atmosphere and Ecosystems

5. Acid Rain Most severe in North Eastern U.S. (Average pH = 4-4.5) Lakes die Forests damaged Symbiotic fungi in tree roots harmed The Atmosphere and Ecosystems

7. Ozone Layer Protects life from harmful UV rays Life can’t exist without it Noticed deterioration in 1978 Large hole over Antarctica Small hole over Arctic The Atmosphere and Ecosystems

8. Ozone Layer Increased UV exposure causes Skin Cancer Cataracts Retina Cancer The Atmosphere and Ecosystems

9. Ozone Layer Destruction caused by CFC’s (chlorofluorocarbons) Coolants (fridges) Aerosol cans (propellants) Foam agent for cups UV light can break bonds in stable CFC’s causing free chlorine atoms to damage ozone CFC’s in spray cans banned in U.S. The Atmosphere and Ecosystems

11. Global Temperatures Global Warming Periods of warm temperatures on Earth Can be caused by sunspots The Atmosphere and Ecosystems

12. Global Temperatures Greenhouse Effect Layer of greenhouse gases (CO2, methane and nitrous oxide) blanket Earth, trapping in heat Increase in greenhouse gases due to burning of fossil fuels The Atmosphere and Ecosystems

17. Assessment • Summarize two harmful effects of acid rain • Differentiate the greenhouse effect from global warming • How might the depletion of the ozone layer affect human health? • Is the greenhouse- gases model adequate to explain all warming of Earth over its existence? Explain why or why not. • Which activity might reduce the severity of the greenhouse effect?

18. Chemical Pollution Lake Erie Heavily polluted Assumed that it could absorb unlimited amounts of chemicals Effects on Ecosystems

19. Chemical Pollution Exxon Valdez Oil Spill Coast of Alaska Extensive damage to marine life Large Scale Small scale leaks account for 90% of pollution by oil Effects on Ecosystems

21. Chemical Pollution Toxic, carcinogenic agents cause most disastrous chemical pollution Effects on Ecosystems

22. Major Chemical Pollution • Basel, Switzerland (1986) • Firefighters accidentally washed mercury and pesticides from a burning building into the Rhine River • Killed enumerable plants and animals • Low biodiversity, still, today

23. Agricultural Chemicals Biological Magnification Pesticides like DDT, break down slowly Accumulate in fatty tissues of animals As molecules pass up through trophic levels, they become more concentrated Effects on Ecosystems

25. Agricultural Chemicals DDT weakens bird egg shells 1972, population numbers of predatory birds dwindled Chemicals still necessary to meet needs of growing human population Effects on Ecosystems

26. Loss of Resources Most alarming problem Overuse and destruction of nonrenewable resources Effects on Ecosystems

27. Extinction of Species Thousands of miles of rainforestdestroyed for timber and farm land Causes loss of many species Biodiversity lost Potential benefits of species, destroyed before discovery Effects on Ecosystems

28. Loss of Species in Rainforests • 10% on verge of extinction • 1 million will become extinct over next 50 years • Extinction rivals that of the dinosaurs

29. Loss of Topsoil U.S. has most fertile soil on planet (due to decayed plant/animal matter) Several cm of topsoil swept away by wind and rain, each decade 1/3 of world’s topsoil lost since 1950 Effects on Ecosystems

30. Loss of Topsoil Caused by Turning over soil to eliminate weeds Overgrazing by animals Poor land management practices Effects on Ecosystems

31. Ground-water pollution and depletion Aquifers- porous rock reservoirs storing ground water Being used at alarming rates for Watering lawn Washing Cars Leaky faucets Polluted by chemical waste disposal Effects on Ecosystems

32. Growth of Human Population Humans first reached N.A. 12,000 yrs ago by crossing Siberia into Alaska Population 5 million Effects on Ecosystems

33. Growth of Human Population Glaciers receded from N.A., agriculture took over Effects on Ecosystems

34. Growth of Human Population By 2000 yrs ago, world population = 130 million Effects on Ecosystems

35. Growth of Human Population 1650- world population = 500 million Effects on Ecosystems

36. Growth of Human Population Current birthrate = 30 births per 1000 people per year Current deathrate= 9 births per 1000 people per year Effects on Ecosystems

37. Growth of Human Population Deathrate continues to decrease due to better sanitation and medical care 1.3% increase in world population each year World population will double within 60 years Effects on Ecosystems

38. World Population Statistics • Current population exceeds 6 billion • 94 million born each year • 260,000 born each day • 180 born each minute

39. Fastest Growing Populations Typically poorer areas Asia Africa (Nigeria GR= 3.05%) Latin America Effects on Ecosystems

40. Slowest Growing Populations North America (.8% gr) Europe Japan New Zealand Australia Effects on Ecosystems

41. Declining Population Germany Russia Effects on Ecosystems

42. World Human Population Predicted to stabilize at 9.7 billion by 2050 Quickly depleting natural resources Task: Building a sustainable world How long will the Earth even sustain the current 6 billion people on the planet? Effects on Ecosystems

45. Assessment • Evaluate how research showing that chlorinated hydrocarbons are an environmental threat may impact people in the U.S. • Summarize why supplies of soil and ground water are dwindling even though these resources are replenished by natural processes • Describe two instances in which technology has caused the growth rate of the human population to increase • A classmate claims that the growth of the human population will not affect populations of other species. Evaluate this viewpoint. • Which organism would have the highest concentration of a pollutant that enters the water and is absorbed by aquatic primary producers? Large fish? Small fish? Fish-eating bird? Zooplankton?

46. Reducing Pollution International agreements to stop CFC production Restrict the releases of toxins (DDT, asbestos, dioxin) Solving Environmental Problems

47. Reducing Pollution Secondary sewage treatment facilities remove chemicals from water Solving Environmental Problems

48. Reducing Pollution Scrubbers on smokestacks reduce coal burning emissions Solving Environmental Problems

49. Reducing Pollution Special traveling lanes for carpoolers Solving Environmental Problems

50. Reducing Pollution in the U.S. Laws restricting what can be released into the environment Catalytic converters on cars Scrubbers on power plant smokestacks Solving Environmental Problems