Biology - Chp 6 - Humans In The Biosphere - PowerPoint

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Biology - Chp 6 - Humans In The Biosphere - PowerPoint

  1. 1. Chapter 6 Humans in the Biosphere
  2. 7. 6 – 1 A Changing Landscape <ul><li>What type of human activities can affect the biosphere? </li></ul>
  3. 8. Earth as an Island <ul><li>All of the organisms, including humans that live on Earth share a limited resource base and depend on it for their long term survival </li></ul><ul><li>To protect these resources we need to understand how humans interact with the biosphere </li></ul>
  4. 9. Human Activities <ul><li>Since we depend on the ecosystem for resources we must be aware that human activities can change the local and global environments </li></ul><ul><li>Among human activities that affect the biosphere include </li></ul>
  5. 10. Hunting and Gathering
  6. 11. Agriculture
  7. 12. Urban Development
  8. 13. The Tragedy of The Commons
  9. 14. 6 – 2 Renewable and Nonrenewable Resources <ul><li>How are environmental resources classified? </li></ul><ul><li>What effect does human activities have on natural resources? </li></ul>
  10. 15. Renewable resource <ul><li>Can regenerate if they are alive or be replenished if they are non-living </li></ul><ul><li>A renewable resource is not necessarily unlimited </li></ul><ul><li>Ex.) water </li></ul>
  11. 16. Nonrenewable resource <ul><li>Cannot be replenished by natural processes </li></ul>
  12. 17. Sustainable development <ul><li>A way of using natural resources without depleting them and without causing long-term environmental harm </li></ul><ul><li>Human activities can affect the quality and supply of renewable resources such as land, forests, fisheries, air, and fresh water </li></ul>
  13. 18. Land Resources <ul><li>If managed properly, soil is a renewable resource </li></ul><ul><li>Soil, however can be permanently damaged if it is mismanaged </li></ul>
  14. 19. Soil erosion <ul><li>The wearing away of surface soil by water or wind </li></ul>
  15. 20. Desertification <ul><li>When once productive areas are turned into deserts </li></ul><ul><li>Caused by: </li></ul><ul><li>Farming </li></ul><ul><li>Overgrazing </li></ul><ul><li>Drought </li></ul>
  16. 21. Sustainable Solutions to guard against these practices <ul><li>Contour plowing </li></ul><ul><li>Leaving stems and roots of the previous years crop in place </li></ul><ul><li>Planting an unused field with rye </li></ul>
  17. 23. Forest Resources <ul><li>Provide wood </li></ul><ul><li>Are considered the lungs of the earth </li></ul><ul><li>Store nutrients </li></ul><ul><li>Provide habitats </li></ul><ul><li>Provide food </li></ul><ul><li>Moderate climate </li></ul><ul><li>Limit soil erosion </li></ul><ul><li>Protect freshwater supplies </li></ul><ul><li>Forests are important because they </li></ul>
  18. 24. Deforestation <ul><li>Loss of forests </li></ul><ul><li>Can lead to severe erosion </li></ul>
  19. 27. Sustainable Solutions for Forest Management <ul><li>Harvest mature trees selectively </li></ul><ul><li>Tree farms </li></ul><ul><li>Tree geneticists </li></ul>
  20. 28. Fishery Resources <ul><li>Fishes and other animals that live in water are a valuable source of food for humanity </li></ul>
  21. 29. Overfishing <ul><li>Harvesting fish faster than they can be replaced by reproduction </li></ul>
  22. 31. Sustainable Solutions for Fisheries <ul><li>The US National Marine Fisheries Service uses data on fish populations to create guidelines for commercial fishing </li></ul><ul><li>Aquaculture – raising aquatic animals for human consumption </li></ul>
  23. 32. Air Resources <ul><li>Air is a common resource that we use every time we breathe </li></ul><ul><li>The condition of air affects peoples health </li></ul><ul><li>The preservation of air quality remains a challenge to modern society </li></ul>
  24. 33. Smog <ul><li>A mixture of chemicals that occurs as a gray-brown haze in the atmosphere </li></ul>
  25. 34. Pollutant <ul><li>A harmful material that can enter the biosphere </li></ul>
  26. 35. <ul><li>Many combustion processes, such as the burning of fossil fuels, releases nitrogen and sulfur compounds </li></ul><ul><li>When these compounds combine with water in the atmosphere they produce nitric and sulfuric acids - which fall to the earth as acid rain </li></ul>
  27. 37. Freshwater Resources <ul><li>Americans use billions of liters of freshwater everyday </li></ul><ul><li>Although water is a renewable resource, the total supply of freshwater is limited </li></ul><ul><li>For this reason, protection of water supplies from pollution is a major priority </li></ul>
  28. 38. Sustainable Solutions <ul><li>Protect natural systems involved with the water cycle </li></ul><ul><li>Ex.) wetlands and forests </li></ul><ul><li>Water treatment facilities </li></ul><ul><li>Drip irrigation </li></ul>
  29. 39. Protect natural systems involved with the water cycle <ul><li>Ex.) Wetlands and Forests </li></ul>
  30. 40. Water Treatment facilities
  31. 41. Drip irrigation
  32. 42. 6 – 3 Biodiversity <ul><li>What is the value of biodiversity? </li></ul><ul><li>What are the current threats to biodiversity? </li></ul><ul><li>What is the goal of conservation biology? </li></ul>
  33. 43. 6 – 3 Biodiversity <ul><li>Variety is the spice of life </li></ul><ul><li>But variety in the biosphere gives us more than just interesting things to look at </li></ul><ul><li>Human society takes place in local and global food webs and nutrient cycles </li></ul><ul><li>For that reason, out well being is closely tied to the well being of a great variety of other organisms </li></ul>
  34. 44. Biodiversity <ul><li>(Biological diversity) – the sum total of the genetically based variety of all organisms in the biosphere </li></ul>
  35. 45. Types of Biodiversity <ul><li>Ecosystem diversity – the variety of habitats </li></ul><ul><li>Species diversity – the variety of species </li></ul><ul><li>Genetic diversity – the variety of genetic info carried by all the organisms </li></ul>
  36. 46. The Value of Biodiversity <ul><li>Biodiversity is one of Earth’s greatest natural resources </li></ul><ul><li>Species of many kinds have provided us with… </li></ul><ul><li>Food </li></ul><ul><li>Industrial products </li></ul><ul><li>medicines </li></ul>
  37. 47. Gum Tree
  38. 48. Rosy Periwinkle
  39. 49. Threats to Biodiversity <ul><li>Human activity can reduce biodiversity by: </li></ul>
  40. 50. Altering habitats
  41. 51. Hunting species to extinction
  42. 52. Introducing toxic chemicals
  43. 53. Introducing foreign species
  44. 54. Endangered Species <ul><li>A species whose population is declining and is in danger of becoming extinct </li></ul>
  45. 55. Extinct <ul><li>When a species disappears from the biosphere </li></ul>
  46. 56. Habitat Alteration <ul><li>When land is developed, natural habitats are destroyed </li></ul>
  47. 57. Habitat fragmentation <ul><li>When development split ecosystems into pieces </li></ul>
  48. 58. Demand for Wildlife Products <ul><li>Throughout history, humans have pushed some animal species to extinction by hunting them for food or other products </li></ul><ul><li>Today, endangered species are protected by laws </li></ul><ul><li>Unfortunately it is difficult to enforce laws in remote wilderness areas </li></ul>
  49. 59. Pollution <ul><li>Many forms of pollution can threaten biodiversity </li></ul><ul><li>One of the most serious problems occurs when toxic compounds accumulate in the tissues of organisms </li></ul><ul><li>Ex.) DDT </li></ul>
  50. 60. Biological magnification <ul><li>When concentrations of harmful substances increase in organisms at higher trophic levels in a food chain </li></ul>
  51. 62. Introduced species <ul><li>One of the most important threats to biodiversity today is introduced species </li></ul>
  52. 63. Invasive species <ul><li>Plants and animals that live in environments they are not native to </li></ul>
  53. 64. Zebra mussel
  54. 65. Leafy Spurge
  55. 66. Mile-a-minute
  56. 67. Nutria
  57. 68. Phragmites
  58. 69. Purple loosestrife
  59. 70. Q: Why do invasive species reproduce rapidly and quickly take over their new habitat? <ul><li>A: Their new habitat lacks the predators and parasites that control their populations “back home” </li></ul>
  60. 71. Conservation <ul><li>The wise management of natural resources including the preservation of habitats and wild life </li></ul>
  61. 72. Strategies for Conservation <ul><li>Managing of a single species </li></ul><ul><li>Ex.) captive breeding </li></ul>
  62. 73. Strategies for Conservation <ul><li>2. Protecting entire ecosystems </li></ul><ul><li>Ex.) setting land aside </li></ul>
  63. 77. Conservation Challenges <ul><li>Protecting resources for the future can require people to change the way they earn their living </li></ul><ul><li>The challenge is to maximize benefits while minimizing economic cost </li></ul><ul><li>But an ecological perspective tells us that if we don’t take some difficult steps today, some resources may disappear and jobs that depend of that resource will be lost permanently </li></ul>
  64. 78. 6 – 4 Charting a Course for the Future <ul><li>What are two types of global change of concern to biologists </li></ul>
  65. 79. 6 – 4 Charting a Course for the Future <ul><li>For most of human history, environmental change was a local affair </li></ul><ul><li>Today, most of Earth’s land surface has been altered by human activity </li></ul><ul><li>In order to plan a sound environmental strategy for the 21st century, we need data provided by research </li></ul>
  66. 80. Ozone Depletion
  67. 81. Ozone layer <ul><li>Part of the atmosphere that contains a relatively high concentration of ozone gas (O 3 ) </li></ul><ul><li>The ozone layer absorbs a good deal of harmful ultraviolet or UV radiation from sunlight before it reaches the Earth’s surface </li></ul>
  68. 84. <ul><li>Over exposure to UV rays causes: </li></ul><ul><li>Sunburn </li></ul><ul><li>Cancer </li></ul><ul><li>Damage to eyes </li></ul><ul><li>Decreased resistance to disease </li></ul>
  69. 85. Early evidence <ul><li>Satellite images in the 1970’s first showed the hole in the ozone layer over Antarctica </li></ul><ul><li>Evidence also showed that chlorofluorocarbons or CFC’s could change the ozone layer </li></ul>
  70. 86. One Solution <ul><li>Reduce the use of CFC’s </li></ul><ul><li>Many CFC’s are now banned </li></ul><ul><li>Ex.) Montreal Protocol signed 1987 </li></ul>
  71. 87. Global Climate Change <ul><li>All life on Earth depends on climate conditions such as temperature and rainfall </li></ul><ul><li>That’s why many ecologists are concerned about strong evidence that Earth’s climate is changing </li></ul><ul><li>Since the late nineteenth century, average atmospheric temperatures on Earth’s surface have risen about 0.6 degrees Celcius </li></ul>
  72. 88. <ul><li>Since 1980 average temperatures have risen .2 and .3 degrees Celcius </li></ul><ul><li>The 1990’s were the warmest decade on record </li></ul><ul><li>1998 was the warmest year since record keeping began </li></ul>
  73. 89. Global Warming <ul><li>Increase in the average temperature of the biosphere </li></ul>
  74. 90. Evidence of Global Warming <ul><li>If is believed that the current warming is related to human activities that are adding CO 2 and other greenhouse gases to the atmosphere </li></ul><ul><li>The burning of fossil fuels combined with cutting and burning of forests worldwide is adding carbon dioxide to the atmosphere faster than the carbon cycle removes it </li></ul><ul><li>As a result, the atmosphere’s natural greenhouse effect is intensified causing the atmosphere to retain more heat </li></ul>
  75. 92. Possible Effects of Global Warming <ul><li>Computer models based on the trends seen in the data suggest that average global surface temperatures will increase by 1 to 2 degrees Celsius by the year 2050 </li></ul>
  76. 93. Q: What might this mean? <ul><li>A: </li></ul><ul><li>Sea levels may rise enough to flood some costal areas </li></ul><ul><li>More droughts in North America </li></ul><ul><li>New organisms will be able to live in places where they once could not </li></ul><ul><li>Other organisms may become threatened or extinct in areas they once thrived </li></ul>
  77. 94. The Value of a Healthy Biosphere <ul><li>Human society depends on healthy, diverse and productive ecosystems because of the environmental and economic benefits they provide </li></ul><ul><li>People can help maintain the health of the biosphere without drastically changing their lifestyles if they make wise choices in the use and conservation of resources </li></ul>
  78. 95. The Future of the Biosphere <ul><li>Studies of human impact on the environment are not about predicting disaster </li></ul><ul><li>You have seen how research has lead to action which is fixing the mistakes of the past </li></ul><ul><li>Remember, the biosphere is strong and we humans are clever. Both humans and natural ecosystems can adapt to change of different kinds </li></ul>

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