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  • 1.  
  • 2. Chapter: Our Impact on Land Table of Contents Section 3: Conserving Resources Section 1: Population Impact on the Environment Section 2: Using Land
  • 3. Population and Carrying Capacity
    • A population is all of the individuals of one species occupying a particular area.
    • The area can be small or large. For example, a human population can be of one community, such as Los Angeles, or the entire planet.
    1 Population Impact on the Environment
  • 4. Earth's Increasing Population
    • The global population in 2000 was 6.1 billion.
    • Each day, the number of humans increases by approximately 200,000.
    1 Population Impact on the Environment
    • Earth is now experiencing a population explosion.
  • 5. Population Growth
    • Human population growth remained relatively steady until the beginning of the nineteenth century.
    • The growth rate then began to increase rapidly.
    1 Population Impact on the Environment
  • 6. Population Growth
    • The human population has increased because modern medicine, clean water, and better nutrition have decreased the death rate.
    1 Population Impact on the Environment
    • By 2050, the population is predicted to be about 9 billion—one and a half times what it is now.
  • 7. Population Growth 1 Population Impact on the Environment
    • Will the things that have helped the population grow, such as improved health care, agriculture, and clean water, be maintainable?
    • Will Earth have enough natural resources to support such a large population?
  • 8. Population Limits
    • Population size depends on the amount of available resources and how members of the population use them.
    1 Population Impact on the Environment
    • If resources become scarce or if the environment is damaged, members of the population can suffer and population size could decrease.
  • 9. Population Limits
    • Earth's resources are limited.
    1 Population Impact on the Environment
    • Carrying capacity is the largest number of individuals of a particular species that the environment can support.
    Click image to view movie.
  • 10. People and the Environment
    • By the time you're 75 years old, you will have produced enough garbage to equal the mass of eleven African elephants (53,000 kg).
    1 Population Impact on the Environment
    • You will have consumed enough water to fill 68,000 bathtubs (18 million L).
  • 11. People and the Environment
    • If you live in the United States, you will have used several times as much energy as an average person living elsewhere in the world.
    1 Population Impact on the Environment
  • 12. Daily Activities
    • Every day you affect the environment.
    1 Population Impact on the Environment
    • The electricity you use might be generated by burning fossil fuels.
    • The water that you use must be treated to make it as clean as possible before being returned to the environment.
    • You eat food, which needs soil to grow.
    Click image to view movie.
  • 13. Daily Activities
    • Much of the food you eat is grown using chemical substances, such as pesticides and herbicides, to kill insects and weeds.
    1 Population Impact on the Environment
    • These chemicals can get into water supplies and threaten the
    health of living things if the chemicals become too concentrated.
  • 14. Daily Activities
    • Plastic begins as oil.
    1 Population Impact on the Environment
    • The process of refining oil can produce pollutants — substances that contaminate the environment.
    • In the process of changing trees to paper, several things happen that impact the environment.
  • 15. Packaging Produces Waste
    • The land is changed when resources are removed from it.
    1 Population Impact on the Environment
    • The environment is further impacted when those resources are shaped into usable products.
    • Unnecessary packaging is only one of the problems associated with waste disposal.
  • 16. The Future
    • As the population continues to grow, more resources are used and more waste is created.
    1 Population Impact on the Environment
    • If these resources are not used wisely and if waste is not managed properly, environmental problems are possible.
  • 17. 1 Section Check Question 1 A. community B. ecosystem C. niche D. population All the individuals of one species occupying a particular area are a(n) __________. NC: 3.06
  • 18. 1 Section Check Answer The answer is D. A population can be of a large or small area. NC: 3.06
  • 19. 1 Section Check Question 2 What does the term “carrying capacity” mean? Answer Carrying capacity is the largest number of individuals of a particular species that the environment can support. NC: 3.08
  • 20. 1 Section Check Question 3 What is the approximate current human population of Earth? A. 600 million B. 1 billion C. 6 billion D. 9 billion NC: 3.08
  • 21. 1 Section Check Answer The answer is C. The current human population of is approximately 6 billion. NC: 3.08
  • 22. Land Usage
    • We use land for agriculture, logging, garbage disposal, and urban development.
    • These activities often impact Earth's land resources.
    2 Using Land
  • 23. Agriculture
    • About 16 million km 2 of Earth's total land surface is used as farmland.
    • Some farmers use higher-yielding seeds and chemical fertilizers.
    2 Using Land
    • Herbicides and pesticides also are used to reduce weeds, insects, and other pests that can damage crops.
  • 24. Agriculture
    • Organic farming techniques use natural fertilizers, crop rotation, and biological pest controls.
    • However, organic farming cannot currently produce enough food to feed all of Earth's people.
    2 Using Land
  • 25. Agriculture
    • Whenever vegetation is removed from an area, such as a construction site or tilled farmland, soil is exposed.
    • Nothing prevents the soil from being carried away by running water and wind.
    2 Using Land
    • In some places, it can take more than 1,000 years for new topsoil to develop.
  • 26. Reducing Erosion
    • Some farmers practice no till farming.
    2 Using Land
    • They don't plow the soil from harvest until planting.
    Instead, farmers plant seed between the stubble left from the previous year.
  • 27. Reducing Erosion
    • Other methods also are used to reduce soil loss.
    • One method is contour plowing.
    2 Using Land
    • The rows are tilled across hills and valleys. When it rains, water and soil are captured by the plowed rows, reducing erosion.
  • 28. Reducing Erosion
    • Other techniques include planting trees in rows along fields.
    • Cover crops, crops that are not harvested, also can be planted to reduce erosion.
    2 Using Land
  • 29. Feeding Livestock
    • Land also is used for feeding livestock.
    • Animals such as cattle eat vegetation and then are used as food for humans.
    2 Using Land
    • About sixty-five percent of the farmland in Texas is used for grazing cattle.
  • 30. Forest Resources
    • Approximately one-fourth of the land area on Earth is covered by forest.
    • The distribution of Earth's forest according to region is shown.
    2 Using Land
  • 31. Forest Resources
    • Deforestation is the clearing of forested land for agriculture, grazing, development, or logging.
    2 Using Land
  • 32. Forest Resources
    • It is estimated that the amount of forested land in the world decreased by 0.24% (94,000 km 2 ) each year between 1990 and 2000.
    2 Using Land
    • Most of this deforestation occurred in tropical regions.
  • 33. Forest Resources
    • Tropical rain forest contain diverse populations of plants and animals that don't live in other places.
    • Some people also worry that removing too much of these forests could lead to the extinction of some organisms.
    2 Using Land
  • 34. Forest Resources
    • Cutting trees can have a regional effect on climate as well.
    • Water from tree leaves evaporates into the atmosphere where it can condense to form rain.
    2 Using Land
    • If many trees are cut down, less water enters the atmosphere and the region receives less rainfall.
  • 35. Development
    • Paving land prevents water from soaking into the soil. Instead, it runs off into sewers or streams.
    • A steam's discharge increases when more water enters its channel.
    2 Using Land
    • Stream discharge is the volume of water flowing past a point per unit of time.
  • 36. Development
    • Many communities use underground water supplies for drinking.
    • Covering land with roads, sidewalks, and parking lots reduces the amount of rainwater that soaks into the ground to refill underground water supplies.
    2 Using Land
  • 37. Development
    • Some communities, businesses, and private groups preserve areas rather than pave them.
    • Land is set aside for environmental protection.
    2 Using Land
    • Preserving space beautifies the environment, increases the area into which water can soak, and provides space for recreation and other outdoor activities.
  • 38. Sanitary Landfills
    • About 60 percent of our garbage goes into sanitary landfills.
    • A sanitary landfill is an area where each day's garbage is deposited and covered with soil.
    2 Using Land
  • 39. Sanitary Landfills
    • The soil prevents the deposit from blowing away, helps decompose some materials, and reduces the odor produced by the decaying waste.
    2 Using Land
  • 40. Sanitary Landfills
    • New sanitary landfills are lined with plastic, concrete, or clay-rich soils that trap the liquid waste.
    2 Using Land
  • 41. Sanitary Landfills 2 Using Land
    • Because of these linings, sanitary landfills greatly reduce the chance that pollutants will leak into the surrounding soil and groundwater.
  • 42. Sanitary Landfills
    • Locating an acceptable area to build a landfill can be difficult.
    2 Using Land
    • Type of soil, the depth to groundwater, and neighborhood concerns must be considered.
  • 43. Hazardous Waste
    • Waste that are poisonous, that cause cancer, or that can catch fire are called hazardous wastes .
    2 Using Land
    • In the 1980s, many states passed environmental laws that prohibit industries from disposing of hazardous wastes in sanitary landfills.
  • 44. Household Hazardous Waste
    • It may seem that when you throw something in the garbage, it's gone and you don't need to be concerned with it anymore.
    2 Using Land
    • Some garbage can remain unchanged in a landfill for hundreds of years.
    • You can help by disposing of hazardous wastes at special hazardous waste-collection sites.
  • 45. Phytoremediation
    • Hazardous substances can contaminate soil.
    2 Using Land
    • Some plants can help fix this problem in a method called phytoremediation (FI toh ruh mee dee AY shun). Phyto means "plant" and remediation means "to fix or remedy a problem."
  • 46. Phytoremediation 2 Using Land
    • During phytoremediation, roots of certain plants such as alfalfa, grasses, and pine trees can absorb metals, including copper, lead, and zinc from contaminated soil just as they absorb other nutrients.
  • 47. Phytoremediation
    • Plants that become concentrated with metals from soil eventually must be harvested and either composted to recycle the metals or burned.
    2 Using Land
  • 48. Phytoremediation
    • If these plants are destroyed by burning, the ash residue contains the hazardous waste that was in the plant tissue and must be disposed of at a hazardous waste site.
    2 Using Land
  • 49. Breaking Down Organic Pollutants
    • Substances that contain carbon and other elements like hydrogen, oxygen, and nitrogen are called organic compounds.
    2 Using Land
    • Organic pollutants can be broken down into simpler, harmless substances, some of which plants use for growth.
  • 50. Breaking Down Organic Pollutants
    • Enzymes are substances that make chemical reactions go faster.
    2 Using Land
    • Enzymes from plant roots increase the rate at which organic pollutants are broken down into simpler substances.
    • Plants use these substances for growth.
  • 51. Natural Preserves 2 Using Land
    • National forestlands, grasslands, and national parks in the United States are protected from
    many problems that you've read about in this section.
  • 52. Natural Preserves
    • In many other countries throughout the world, land also is set aside for natural preserves.
    2 Using Land
    • Preserving some land in its natural state will benefit future generations.
  • 53. 2 Section Check Question 1 What is deforestation? Answer Deforestation is the clearing of forested land for agriculture or industry. NC: 3.06
  • 54. 2 Section Check Question 2 What is a primary benefit of farming practices such as no-till farming and contour plowing? Answer These practices reduce soil loss. Other techniques used to reduce soil erosion are planting cover crops and rows of trees along fields. NC: 3.06, 3.07, 3.08
  • 55. 2 Section Check Question 3 __________ is the volume of water flowing past a point per unit of time. A. Pollution B. Rainfall C. Runoff D. Stream discharge NC: 3.01
  • 56. 2 Section Check Answer The answer is D. A stream’s discharge increases when more water enters its channel. NC: 3.01
  • 57. Resource Use
    • Resources such as petroleum and metals are important for making the products you use every day at home and in school.
    • Conservation is the careful use of earth materials to reduce damage to the environment.
    3 Conserving Resources
    • Conservation can prevent future shortages of some materials, such as certain metals.
  • 58. Reduce, Reuse, Recycle
    • Developed countries such as the United States use more natural resources than other regions.
    • Ways to conserve resources include reducing the use of materials, and reusing and recycling materials.
    3 Conserving Resources
  • 59. Reduce, Reuse, Recycle
    • You can reduce the consumption of materials in simple ways, such as using both sides of notebook paper or carrying lunch to school in a nondisposable container.
    • Reusing an item means finding another use for it instead of throwing it away.
    3 Conserving Resources
  • 60. Reusing Yard Waste
    • If you cut grass or rake leaves, you can compost these items instead of putting them into the trash.
    • Composting means piling yard wastes where they can decompose gradually.
    3 Conserving Resources
    • Decomposed material provides needed nutrients for your garden or flower bed.
  • 61. Recycling Materials
    • Using materials again is called recycling .
    • Paper makes up about 40 percent of the mass of trash.
    3 Conserving Resources
    • Americans throw away a large amount of paper each year.
  • 62. Recycling Materials 3 Conserving Resources
    • People in the United States throw away enough office and writing paper each year
    to build a wall 3.6 m high stretching from New York City to Los Angeles.
  • 63. Recycling Materials 3 Conserving Resources
    • Recycling this paper would use 58 percent less water and generate 74 percent less air pollution than producing new paper from trees.
  • 64. Recycling Materials
    • Companies can recover part of the cost of many materials by recycling the waste.
    3 Conserving Resources
    • Some businesses use scrap materials such as steel to make new products.
    • These practices save money, benefit the environment, and reduce the amount of waste sent to landfills.
  • 65. Recycling Methods
    • Many states or cities have some form of recycling laws.
    3 Conserving Resources
    • In some places people who recycle pay lower trash collection fees.
    • In other places a refundable deposit is made on all beverage containers.
  • 66. Recycling Methods
    • There are several disadvantages to recycling.
    3 Conserving Resources
    • More people and trucks are needed to haul materials separately from your trash.
    • The materials then must be separated at special facilities.
  • 67. Recycling Methods
    • In addition, demand for things made from recycled materials must exist, and items made from recycled materials often cost more.
    3 Conserving Resources
  • 68. The Population Outlook
    • It's unlikely that the population will begin to decline in the near future.
    3 Conserving Resources
    • To make up for this, resources must be used wisely.
    • Conserving resources by reducing, reusing, and recycling is an important way that you can make a difference.
  • 69. 3 Section Check Question 1 Piling yard wastes where they can decompose gradually is __________. A. composting B. mulching C. recycling D. reusing NC: 3.06, 3.08
  • 70. 3 Section Check Answer The answer is A. Composting can greatly reduce the amount of trash put in landfills. NC: 3.06, 3.08
  • 71. 3 Section Check Question 2 What is conservation? Answer Conservation is the careful use of earth materials to reduce damage to the environment. NC: 3.06, 3.08
  • 72. 3 Section Check Question 3 Using materials again is called __________. A. composting B. conservation C. preservation D. recycling NC: 3.06, 3.08
  • 73. 3 Section Check Answer The answer is D. Recycling has helped to decrease the amount of trash put into landfills. NC: 3.06, 3.08
  • 74. To advance to the next item or next page click on any of the following keys: mouse, space bar, enter, down or forward arrow. Click on this icon to return to the table of contents Click on this icon to return to the previous slide Click on this icon to move to the next slide Click on this icon to open the resources file. Help Click on this icon to go to the end of the presentation.
  • 75. End of Chapter Summary File