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Using Resources Wisely

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1 Using Resources Wisely
Read the lesson title aloud to students.

2 Learning Objectives Describe how human activities affect soil and land. Describe how human activities affect water resources. Describe how human activities affect air resources. Click to reveal each of the learning objectives. To engage students in this lesson and build a background, obtain a recording of Woody Guthrie’s Dust Bowl Ballads and play the song “The Great Dust Storm” for students. Lyrics for this song can be found online. Explain that Guthrie, one of America’s great folksingers, lived during a period called the Dust Bowl that occurred in the Great Plains during the 1930s. Describe the huge dust storms that occurred during the Dust Bowl. Distribute the worksheet for this lesson and tell students to use it to create a concept map to organize the information in this lesson. Make sure students understand that at the end of the presentation, they should be able to describe how human activities affect soil and land, water, and air resources.

3 Soil Resources Healthy soil supports both agriculture and forestry.
The mineral- and nutrient-rich portion of soil is called . Ask: Why is soil important? Answer: Healthy soil supports both agriculture and forestry. Explain to students that both the nutrient content of soil and its structure are produced by long-term interactions between inorganic soil particles and a complex community of plants, fungi, and microorganisms. Ask for a volunteer to verbally complete the statement shown. If the volunteer needs a hint, say that this is something with which he or she is very familiar. Click to reveal the correct answer. Tell students: Good topsoil contains organic matter that absorbs and retains moisture yet allows water to drain. Healthy soil also contains fungi that help plant roots function and bacteria that participate in nutrient cycles. For this reason, soil includes both abiotic and biotic factors that strongly affect the health, stability, and productivity of an ecosystem. Explain that this kind of soil is a renewable resource that can take centuries to form, but can be lost quickly. If soil is lost or badly damaged, that environmental change can impact ecosystem stability. Tell students that during the 1930s, a severe drought in the Great Plains combined with years of poorly managed farming to produce an ecological disaster. Point out that the image shown is one that was taken during that time. Explain to students that a large area essentially turned to desert, or, as it came to be known, a “dust bowl,” as shown in the picture. Many thousands of people lost their jobs and homes. topsoil

4 Soil Erosion Erosion is the removal of soil by water or wind.
The process of turning farmland into desert is called ________________. desertification Ask: What caused the loss of ecosystem stability that lead to the Dust Bowl? Answer: The Dust Bowl of the 1930s was caused, in part, by conversion of prairie land to cropland in ways that left soil vulnerable to erosion. Explain that soil erosion is the removal of soil by water or wind. Soil erosion increases when plowed land is left barren between plantings. Without roots to hold topsoil in place, its minerals, organic matter, and community of microorganisms are easily washed away. Ask for a volunteer to complete the statement. Click to reveal the correct answer. Tell students: In places with dry climates, poor farming practices, overgrazing, drought, and climate change can turn farmland into desert in a process called desertification. Direct students to study the map of desertification risk for North and South America. Tell them that the U.S. Department of Agriculture assigns desertification risk categories based on soil type and climate. Click to zoom in on just the United States portion of the map. Tell students to find their approximate location on the map. Ask: In what category of desertification risk is our area? Answer: Answers will vary with your location. Point out to students that desertification is what happened to the Great Plains in the 1930s. Tell students that today, roughly 40 percent of Earth’s land is at risk for desertification. Ask: What factors put a region at risk for desertification? Answer: A dry climate combined with farming, overgrazing, seasonal drought, or climate change put a region a risk for desertification. Ask: Why isn’t the eastern United States at risk for desertification? Answer: That region of the United States doesn’t have a dry climate.

5 Deforestation Healthy forests: protect fresh water
absorb carbon dioxide moderate climate Deforestation , or loss of forests, can have negative effects on soil quality. Explain to students that healthy forests hold soil in place and offer important ecosystem goods and services by protecting the quality of fresh water supplies, absorbing carbon dioxide, and moderating local climate. Deforestation can permanently change the physical structure and biological community in soil. Tell students that in mountainous regions, removal of trees leads to soil erosion, which can cause mudslides and affect water quality in streams and rivers. Grazing or plowing after deforestation further changes the soil ecosystem in ways that can slow down the process of succession that enables forest regrowth. Point out that more than half of the world’s old-growth forests (forests that had never been cut) have already been logged. In some places, such as the eastern United States, areas that have been carefully logged can undergo secondary succession, so forests can regrow. In tropical rain forests, on the other hand, topsoil is thin, and organic matter decomposes rapidly under high heat and humidity. If small areas of tropical rain forests are cleared for timber, secondary succession can sometimes occur and restore biodiversity. But if those areas are cleared for agriculture, the fungal and microbial communities in the soil are changed dramatically in ways that prevent succession and forest regrowth. Explain that even under ideal conditions, succession takes centuries to produce mature, fully diverse forests in areas that have been logged. For this reason, old-growth forests are usually considered nonrenewable resources. Click to reveal a statement that summarizes what has been said. Ask a volunteer to complete the statement. Click to reveal the correct answer.

6 Soil Use and Sustainability
Best practices in agriculture and forestry: leaving stems and roots crop rotation contour plowing terracing selective harvesting Ask: How can we protect soil? Answer: Best practices in agriculture and forestry can minimize soil erosion. Explain to students that soil is most vulnerable to erosion when it is completely bare. Best practices in agriculture and forestry can minimize soil erosion. Click to reveal the first best practice. Tell students that leaving stems and roots of the previous year’s crop in the soil can help hold soil in place between plantings. Click to reveal another best practice. Explain that because different plants take different nutrients from soil, crop rotation—planting different crops at different seasons or in different years—can help prevent both erosion and nutrient loss. Tell students that careful plowing can also limit erosion. Contour plowing, as shown in the picture, involves planting fields of crops across, instead of down, the slope of the land. This can reduce water runoff and erosion. Explain that similar to contour plowing, terracing—shaping the land to create level “steps”—helps hold water and soil in place. Click to reveal the last best practice. Point out to students that sustainable forestry options also exist. Selectively harvesting mature trees can promote the growth of younger trees and preserve the forest ecosystem, including its soil. In the southeastern United States, conditions enable foresters to plant, harvest, and replant tree farms. A well-managed tree farm both protects the soil and makes the trees themselves a renewable resource.

7 Freshwater Resources Fresh water is considered a renewable resource, but supplies are limited. The Ogallala aquifer is expected to run dry within decades. Tell students that only 3 percent of Earth’s water is fresh water—and most of that is locked in ice at the poles. Since we can’t infinitely expand our use of a finite resource, we must protect the ecosystems that collect and purify fresh water. As a discussion point, hold up a gallon of bottled water and a glass of tap water. Ask: What are the sources for these two types of water? Answer: Most tap water is produced at a local water plant or comes from a well; sources vary, but about one fourth of bottled water comes from municipal water supplies, the same source as tap water. Ask: What happens to the bottle after the water is consumed? Answer: It’s usually thrown away; sometimes it’s recycled. Have students assess which water—bottled or tap—uses more of Earth’s resources and judge which is a wiser use of those resources. Explain that humans depend on fresh water and freshwater ecosystems for goods and services, including drinking water, industry, transportation, energy, and waste disposal. Much of America’s farmland relies heavily on irrigation, in which fresh water is brought in from other sources. Unfortunately, some of those sources are not renewable. Click to reveal information about the Ogallala aquifer. Tell students: The Ogallala aquifer spans eight states from South Dakota to Texas. Water collected in this aquifer long ago, over a period of more than a million years, when the area received ample rainfall. Today, water removed from this aquifer is not replaced by rainfall. So much water is being pumped out that the Ogallala is expected to run dry within decades.

8 Water Pollution Industrial and agricultural chemicals
10,000,000 Fish-eating birds Industrial and agricultural chemicals Residential sewage Nonpoint sources Large fish 1,000,000 100,000 Small fish 10,000 Zooplankton Tell students that a pollutant is a harmful material that can enter the biosphere. Explain to students that freshwater sources can be affected by different kinds of pollution. Sometimes pollutants enter water supplies from a single source—a factory or an oil spill, for example. This is called point source pollution. Often pollutants enter water supplies from many smaller sources—the grease and oil washed off streets by rain or the chemicals released into the air by factories and automobiles. These origins of pollutants are called nonpoint sources. Tell students that pollutants may enter both surface water and underground water supplies that we access with wells. Once contaminants are present, they can be extremely difficult to remove. Point out the primary sources of water pollution: - Industrial and agricultural chemicals - Residential sewage - Nonpoint sources Explain to students that biological magnification occurs if a pollutant, such as DDT, mercury, or a PCB, is picked up by an organism and is not broken down or eliminated from its body. Click to show this information. Ask: What does the illustration represent? Answer: a food chain Point out that the pyramid shows the concentration of DDT as orange dots in each trophic level. Tell students: The pollutant collects in body tissues. Step students through the process. A pollutant is introduced into the environment through, for example, water. Click to highlight the pollutant in water. Primary producers pick up a pollutant from the environment. Click to highlight the primary producers. Herbivores like zooplankton that eat those producers concentrate and store the compound. Pollutant concentrations in herbivores may be more than ten times the levels in producers. Click to highlight the zooplankton herbivores. When carnivores eat the herbivores, the compound is further concentrated. Thus, pollutant concentration increases at higher trophic levels. Click to highlight the small fish. In the highest trophic levels, pollutant concentrations may reach 10 million times their original concentration in the environment. Click to highlight the higher trophic levels. Explain to students that these high concentrations can cause serious problems for wildlife and humans. Widespread DDT use in the 1950s threatened fish-eating birds like pelicans, osprey, falcons, and bald eagles. It caused females to lay eggs with thin, fragile shells, reducing hatching rates and causing a drop in bird populations. Tell students that since DDT was banned in the 1970s, bird populations have recovered. Still a concern is mercury, which accumulates in the bodies of certain marine fish such as tuna and swordfish. Ask: By what factor is the concentration of DDT multiplied at each successive trophic level? Answer: ten 1,000 Producers Water 1

9 Water Pollution In a food chain, the concentration of
Fish-eating birds 10,000,000 Large fish 1,000,000 In a food chain, the concentration of a pollutant as the number of organisms at a trophic level . increases Small fish 100,000 decreases Zooplankton 10,000 Ask: How would you explain the process of biological magnification? Answer: Biological magnification is the process by which a pollutant becomes more concentrated in the bodies of organisms at higher trophic levels. Ask for a volunteer to verbally fill in the blanks of the statement shown using the words “decreases” and “increases.” Click to reveal the correct answers. Producers 1,000 Water 1

10 Water Quality and Sustainability
Preserve ecosystems to protect watersheds Conserve water Tell students that one key to sustainable water use is to protect ecosystems involved in the natural water cycle. As water flows slowly through a wetland, densely growing plants absorb nutrients and filter out certain pollutants. Similarly, forests and other vegetation help purify water that seeps into the ground or runs off into rivers and lakes. Click to reveal the first item on this slide. Explain that preserving ecosystems is a critical part of protecting a watershed—the area whose groundwater, streams, and rivers drain together into a large lake or river. Cleaning up the pollution in a local area can’t do much good if the water running into it is polluted. The entire watershed must be protected to achieve long-lasting results. Make sure students understand the idea behind watershed conservation—that cleaning up pollution in a local area does no good if nothing is done about water pollution elsewhere in the watershed. Show students a map of their state or their region. Have them identify a river that runs through or close to their community. Then, have them try to identify the watershed of which their river is part. Ask: Into what body of water does that river run? What river runs into that river? Answers: Student answers will vary with location. Suggest various places where the watershed might be polluted and have students identify communities downstream from that source that would be affected by the pollution. Click to reveal the second item on this slide. Explain to students that conserving water is also important. One example of water conservation in agriculture is drip irrigation, which delivers water drop by drop directly to the roots of plants that need it.

11 Atmospheric Resources and Pollutants
Smog Acid rain Greenhouse gases Particulates Ask: How would you compare and contrast the atmosphere as a resource with fresh water as a resource? Answer: Both the atmosphere and fresh water are needed for healthy ecosystems, and both can be contaminated with pollutants. Fresh water is usually considered a renewable resource, though some sources of fresh water are not renewable. Fresh water may be possible to treat if it’s polluted. The atmosphere is never used up, so it is neither renewable nor nonrenewable. To protect the atmosphere, we need to prevent pollutants from being released in the first place. Ask: What are the major forms of air pollution? Answer: Common forms of air pollution include smog, acid rain, greenhouse gases, and particulates. Click to reveal this answer. Explain to students that certain kinds of air pollution can increase the number and severity of respiratory illnesses such as asthma. Changes in the composition of the atmosphere can cause global climate change. Ask: What causes these kinds of changes? Answer: Industrial processes and the burning of fossil fuels can release several kinds of pollutants. Tell students: One kind of air pollution is smog, which is a gray-brown haze formed by chemical reactions among pollutants released into the air by industrial processes and automobile exhaust. Point out that the image shows the major city Beijing, China, where smog is an enormous issue. Ask: What component of smog is beneficial when part of the atmosphere but harmful when at ground level? Answer: ozone Explain that ozone is one product of the chemical reactions among pollutants. Although ozone high in the atmosphere serves an important function, ozone and other pollutants at ground level threaten human health, especially for people with respiratory conditions. Tell students that burning fossil fuels and wood releases stored carbon as carbon dioxide, a greenhouse gas. Agricultural practices, ranging from feeding grain to cattle to several methods of growing rice, release methane, another greenhouse gas. If greenhouse gas concentrations in the atmosphere rise significantly, they can contribute to global warming and climate change. Explain that particulates are microscopic particles of ash and dust released by certain industrial processes and certain kinds of diesel engines. Very small particulates can pass through the nose and mouth and enter the lungs, where they can cause serious health problems.

12 Air Pollution: Acid Rain
Formed by the chemical transformation of nitrogen and sulfur Explain to students that when we burn fossil fuels in factories and homes, we release nitrogen and sulfur compounds that can disrupt natural nutrient cycles in unexpected ways. When those compounds combine with water vapor in the air, they form nitric and sulfuric acids that can drift for many kilometers before they fall as acid rain or snow. Tell students: Acidic water vapor can also affect ecosystems as fog. In some areas, acid rain kills plants by damaging their leaves and changing the chemistry of soil and surface water. Acid rain can also damage stone statues and buildings. Acid precipitation can dissolve and release mercury and other toxic elements from soil, freeing those elements to enter other parts of the biosphere. Ask: What human activities produce the nitrogen and sulfur compounds that result in acid rain? Answer: the burning of fossil fuels Point out that fossil fuels are burned in homes in addition to factories. Ask: What do most Americans use in their homes that ultimately is derived from the burning of fossil fuels? Answer: They use electricity, which is often produced in coal-fired or oil-fired power plants. Home heating is also usually generated by either oil or natural gas. Statues and buildings Plant life

13 Air Quality and Sustainability
Automobile emission standards and clean-air regulations have improved air quality in some regions. Explain to students that improving air quality is difficult. Air doesn’t stay in one place and doesn’t “belong” to anyone. Automobile emission standards and clean-air regulations have improved air quality in some regions, however, and seem to be having a net positive effect. Direct students to consider the data provided in the graph. Tell students that this graph summarizes EPA findings of the total percentage change from 1980 to 2007 in vehicle miles traveled, energy consumption, and the combined emissions of six common pollutants—carbon monoxide, lead, nitrogen oxides, organic compounds, particulates, and sulfur dioxide. Ask: In 1980, motorists in the Puget Sound region of Washington State traveled 36.4 million miles. Assuming that these motorists increased their miles traveled at the national rate, approximately how many miles did they travel in 2007? Answer: 72.8 million miles Click to highlight that the vehicle miles traveled between 1980 and 2007 increased by about 100 percent. Tell students that efforts like the automobile emissions standards and clean-air regulations also have improved the atmosphere globally. Explain to them that at one time, all gasoline was enriched with lead. But as leaded gasoline burned, lead was released in exhaust fumes and ultimately washed onto land and into rivers and streams. Efforts in the United States to phase out leaded gasoline started in 1973 and were completed in 1996 when the sale of leaded gasoline was banned. Now that unleaded gasoline is used widely across the United States, lead levels in soils, rivers, and streams around the country have dropped significantly from earlier, higher levels.

14 industrial and agricultural chemicals
Overview Healthy supports both agriculture and forestry. Best practices can minimize soil . The primary sources of water pollution are: soil erosion industrial and agricultural chemicals residential sewage Review with students the key points of this lesson. Ask students to verbally fill in the missing word in the first statement. Click to reveal the correct answer. Read the completed statement aloud. Ask for a volunteer to verbally complete the second statement. Tell students: Best practices in agriculture and forestry can minimize soil erosion. Ask volunteers to write the primary sources of water pollution. Click to reveal the correct answers. Note that the answers can be in any order. nonpoint sources

15 Student Worksheet Answers
Remind students that they should have used their worksheet throughout the lesson to help them organize the information presented. Allow students time to work in small groups and compare their notes. Encourage discussion regarding the important “take-aways” from the lesson. Worksheet Answers: Students’ concept maps will vary greatly, but they all should contain information regarding how human activities affect soil and land, water, and air resources. They should all have information comparable to the following: - Healthy soil supports both agriculture and forestry. - Best practices in agriculture and forestry can minimize soil erosion. - The primary sources of water pollution are industrial and agricultural chemicals, residential sewage, and nonpoint sources.

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