Human Impact on Earth Resources  UNIT 7  STANDARDS: NCES 2.2.2,  LESSON 3

Lesson Objectives  In this lesson, you will learn about: – Why all populations require natural resources to exist – How the use of natural resources affects the Earth’s land, air, and water – Impact of “developed” countries versus “under developed” countries as standard of living and energy use.

Populations & the Use of Resources  Basic Needs  Populations have the following basic needs: – Air, Food, Water, Shelter, Energy  Organisms adapt to their environment (use the available resources to live)  Beavers modify their environment to build a pond to meet their needs.  Humans have the greatest capacity to modify the environment and natural resources to live their lifestyle.

Population Growth  Impact on Environment  Limits on Populations Limits on Populations  As populations grow, so does the demand on the resources.  Development of cities required more water, food, and shelter.  Populations grow in response to the availability of resources.  Carrying capacity: Max population the resources can support  Overpopulations generally die back to the carrying capacity of the resources.

Environmental limits  Limits  Drought Drought  Famine Famine  Density Independent Factor: affects the entire population regardless of size (flood, drought)  Density Dependent Factor:Based on size of population (food, water)  Human populations are still growing. The Plague in the 1350’s was the last time population decreased.  What will happen when the resources of the Earth reach their carrying capacity?

Section Review  Why do populations stop increasing when they reach the carrying capacity?  Why is a hurricane a density independent factor that limits population growth?  Suppose bacteria is placed in a petri dish with limited resources. What will happen to the population over time?  What might happen if the human population exceeds the carrying capacity of an area?

Human Impact on Land Resources  Surface mining  Underground Mining  Farming  Mining changes the land surface but it can be reclaimed.The land is mined for the resources for humans.  Mining underground produces large amounts of waste material. Rain can cause toxic runoff. Reclamation.  Clearing of land to produce fields to grow crops changes the ecosystem. Desire for increased yields changes the organisms. (Genetic engineering)  Increased use of pesticides and fertilizers to meet demand have an impact on the ecosystem.

Human Impact on Land Resources  Forestry  Urban Development Urban Development  Clearing of forest leads to a loss in topsoil. Reforestation replants the trees for the next generation.  Humans convert farm land and forests into cities.  Urban expansion is the cause of the greatest loss of farmland in the US  Urbanization leads to issues with water, waste, and need for more energy.

Solutions to Human Impact  Land reclamation restores the mining areas to usable tracts of land and forests.  Conservation of wetlands can be recreated.  Waste disposal plants are different from dumps. The plants harvest the energy and resources from our waste or trash.The plants harvest the energy and resources from our waste or trash.  Bioremediation is the use of bacteria to clean up toxic waste, oil spills, etc.toxic wasteoil spills

Section Review  What are some ways that mining activity affect the land surface?  Compare the positive and negative aspects of pesticide use in farming.  How has the urbanization affected the local land and the environment?  If fertilizers do harm to the environment, why are farmers allowed to use them?

Human Impact on Air  Smog Smog  Global Warming Global Warming  Ozone Depletion Ozone Depletion  Acid Rain Acid Rain  Brown haze seen in cities caused by nitrogen gas emissions from cars. May cause breathing difficulties for people with asthma.  Explores the Greenhouse Effect on the air temperature.Increased use of fossil fuels.  It may also be described as a natural cycle of the earth.  Use of chemicals that destroy the protective ozone layer in the stratosphere. Holes allow for more harmful radiation to reach the surface of the earth.  Rain is nature’s way of cleaning the atmosphere. Recall discussion on Acid rain and the effects on ecosystems.

Reducing Air Pollution  Air pollution travels with the wind. Therefore neighboring countries must also be involved. Consider the economic costs.  1990 Clean Air Act set specific reduction goals on sulfur dioxide by EPA enforcement.  Many coal burning power plants are equipped with a scrubber to reduce emissions of gases and particles.  US now uses low sulfur coal for energy production.  10% of the vehicles today contribute to 50-60% of all air pollution generated by gas engines. Need to replace older cars with more efficient and cleaner ones. CO$T$

Section Review  Name 2 forms of pollutants found in the air. What are some natural and man-made sources of these pollutants?  How is global warming related to the greenhouse effect?  At some point, humans will run out of inexpensive coal resources. What impact might this have on global warming?

Human Impact on Water  Point Source Point Source  Non-point Source Non-point Source  Groundwater Pollution Groundwater Pollution  Ocean Pollution Ocean Pollution  Pollution generated from a single source. This may include sewage or industrial discharge.  Pollution carried by rainwater or run-off from the land. Parking lots & farms  The leaking of contaminants into the groundwater from septic tanks, fertilizers, or underground storage.  Pollution from cities destroy estuaries by sewage. Human wastewater is high in nitrogen and phosphorus. This leads to algae blooms. Man also “dumps” trash from cities into the oceans causing more issues.

Reduce & Conserve Water  1974 Safe Water Drinking Act and Clean Water Drinking Act were enacted to ensure clean drinking water to US citizens.  Goal to eliminate pollutants being discharged into the rivers and water supply  However in 1998, 35% of rivers were still in violation.  Water conservation recycle water as a means to conservation. Increasing the use of recycled water.  Using more efficient sprinklers in conjunction with reclaimed water helps reduce the demand for drinking water.  Landscaping with plants that require less eater and raising water prices have also impacted the use of irrigation.  Leaky faucets in the home account for 20-35% water loss from public supplies.  Water meters tend to spot problems so they can be fixed.

Section Review  What are some ways in which surface water can be polluted?  What are some ways to minimize the need for irrigation?  What are some positive impacts of the Clean Water Act?  What type of pollution is easier to eliminate: point source or non-point source? Give examples and propose a way to control the pollution.