Chapter 20 section 1 notes (population impact on the environment)


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Chapter 20 section 1 notes (population impact on the environment)

  1. 1. Section 1: Population Impact on the Environment
  2. 2. A. Population: 1. What is Population? a. All of the individuals of one species occupying a particular area. 2. Can population size vary? a. A population could be the residents of Minersville or all of the residents of Pennsylvania. b. The area defined could be small or large.
  3. 3. B. Population Growth 1. What is our current population? a. The Global Population is approximately 6.8 billion (May 1, 2010). 2. Does our population change? a. Each day the population increases between 200,000 to 300,000 people per day. 3. What is currently happening to our population? a. Earth is currently experiencing a population explosion. b. Explosion is used because the rate at which the population is growing has increased rapidly in recent history.
  4. 4. Figure2:Human Populationgrowth remainedrelatively steadyuntil the beginningof the nineteenthcentury. Thegrowth rate thenbegan to increaserapidly.Why do youthink thisoccurred?
  5. 5. C. Why the population growth? 1. Many years ago few people lived on Earth. a. Took thousands of years for the population to reach 1 billion. 2. After mid 1800’s population increased much faster. a. Changes in society and the advances in civilization helped create the population explosion.
  6. 6. D. Three Major Reasons for Population Explosion 1. Modern Medicine (Better Medicine) a. Reduced infant deaths dramatically. b. Increased the ability to reproduce (fertility drugs). c. Allows people to live longer. 2. Modern Sanitation a. Drinking water cleaned before use. b. Wastes disposed of more safely. c. People have better hygiene. (cleaner)
  7. 7. D. Three Major Reasons for Population Explosion 3. Better Nutrition a. Food better distributed and more readily available. b. Aid given to areas in famine. (3rd world countries)
  8. 8. E. Future Predictions About Population 1. How fast will the population grow? a. By the year 2050 there will be 9 Billion people on Earth. b. About 1.5 times more than today. 2. What is the biggest problem facing the planet today? a. Biggest question is will Earth have enough resources to support such a large population? b. Not if we continue at our current pace of pollution and wasting resources.
  9. 9. F. Population Limits 1. Population size depends upon the amount of available resources and how members of the population use them. 2. If resources become scarce or if the environment is damaged, members of the population can suffer and population size can decrease.
  10. 10. F. Population Limits 3. Earth An Endless Supply of Resources? a. People once believed that Earth had an endless supply of resources such as fossil fuels, metals, rich and fertile soils, and clean water. b. We now know that is NOT TRUE! c. Earth’s resources are LIMITED. 4. What is Carrying Capacity? a. Carrying Capacity is the largest number of individuals of a particular species that the environment can support. b. Unless Earth’s resources are treated with care, they could disappear and the human population might reach its carrying capacity!!
  11. 11. A. How will you affect the environment over your lifetime? 1. How much Garbage will you produce? a. By the time you are 75 years old, you will have produced enough garbage to equal the mass of eleven African Elephants. b. 53,000 kg or 116,600 pounds 2. How much water will you use? a. You will have consumed enough water to fill 68,000 bathtubs. b. 18 million Liters. 3. How much energy will you use? a. United States Citizens use 5X more energy than anyone else.
  12. 12. B. Daily Activities that affect the Environment 1. Electricity a. May be created by burning fossil fuels; polluting the environment. 2. Fossil Fuels a. Fossil Fuels are mined causing damage to the environment. b. Fossil Fuels are burned, polluting the environment. 3. Water: Drinking and Waste Water a. Many people waste water; a valuable resource. b. Water must be treated correctly before it is put back into rivers/streams. i. Raw sewage used to be released directly into rivers and streams without being treated.
  13. 13. B. Daily Activities that affect the Environment 4. Food We Eat a. Grown in soil, using valuable nutrients and minerals. b. Pesticides and Herbicides used to kill insects and weeds; these chemicals can get into water supplies and threaten health of living things if the chemicals become too concentrated. 5. Plastics/Paper Products a. Plastics begin as oil; the process of refining oil can cause pollutants that contaminate the environment. b. Paper; products come from the foresting of trees, oil is used to transport the materials to paper mills, and water and air pollutants are given off in the papermaking process.
  14. 14. C. Packaging Produces Waste 1. Packaging foods for single servings uses more paper and plastic than buying food in bulk. 2. After the products are consumed the packaging must be discarded using up valuable land The land is changed when resources are resources. removed from it, then further damaged when they must be discarded.
  15. 15. D. Our Future? 1. Greater Population means more resources will be used. 2. Greater population means more waste will be created. 3. Greater population means more environmental problems for our planet. 4. People need to conserve more resources, recycle more materials, and help lessen the negative impact our current society places on our environment.