Section 6-1 Leaving a Mark on the World Have you ever seen very old photographs of the town or city in which you now live? Has your area changed? Perhaps there are more buildings or roads than there were many years ago. Maybe your town or city has more trees and flowers now than it had years ago. Humans, like all organisms, have an effect on their environment. Go to Section: Interest Grabber continued Section 6-1 1. Choose an animal other than a human and describe at least two ways in which it may change its environment. 2. What events might have led to the changes that occurred in your town or city? 3. What positive effect have humans had on their environment? What negative effect have humans had on their environment? Go to Section: Section Outline Section 6-1 6–1 A Changing Landscape A. B. C. D. Earth as an Island Human Activities Hunting and Gathering Agriculture 1. From Traditional to Modern Agriculture 2. The Green Revolution 3. Challenges for the Future E. Industrial Growth and Urban Development Go to Section: Concept Map Section 6-1 Human Activities that have changed the biosphere include Hunting and gathering may have once caused Industrial growth Agriculture often relies on the methods of the Extinctions of large animals Green revolution Food supply Go to Section: Pesticide use have resulted in High standard of living which increased Monoculture use Urban development Increased pollution Interest Grabber Section 6-2 Where Do Natural Resources Come From? Natural resources are materials that are supplied by nature. A renewable resource is one that is replaceable. A nonrenewable resource is one that cannot be replenished by natural processes. Once a nonrenewable resource is used up, it is gone forever. Go to Section: Interest Grabber continued Section 6-2 1. Examine the list of natural resources shown below. Then, classify each natural resource as either renewable or nonrenewable. a. b. c. d. e. Wood Fossil fuels Aluminum Wool Gold 2. Describe the impact that the loss of nonrenewable resources would have on the environment. Go to Section: Section Outline Section 6-2 6–2 Renewable and Nonrenewable Resources A. B. C. D. E. Classifying Resources Sustainable Development Land Resources Forest Resources Fishery Resources 1. Overfishing 2. Sustainable Development 3. Aquaculture F. Air Resources G. Freshwater Resources Go to Section: Growth of Fish Catch Section 6-2 World Fish Catch Amount of Fish per Person (kilograms) Total Catch (million tons) Year Go to Section: World Fish Catch per Person Year Figure 6-12 The Formation of Acid Rain Section 6-2 Emissions to Atmosphere Nitrogen oxides Sulfur dioxide Chemical Transformation Nitric acid Sulfuric acid Condensation Dry Fallout particulates, gases Industry Go to Section: Transportation Ore smelting Power generation Precipitation Acid rain, fog, snow, and mist Interest Grabber Section 6-3 What Is Biodiversity? Biodiversity is the sum total of the variety of organisms in the biosphere. Sometimes humans can reduce biodiversity, which is considered a natural resource. Go to Section: Interest Grabber continued Section 6-3 1. List three ways in which other organisms have proved to be a benefit to humans. 2. Compare biodiversity with other natural resources, such as wood and fossil fuels. Do you think biodiversity is a renewable or a nonrenewable resource? Explain your answer. 3. What can be done to preserve the biodiversity of organisms? Go to Section: Section Outline Section 6-3 6–3 Biodiversity A. B. C. D. E. F. G. Go to Section: The Value of Biodiversity Threats to Biodiversity Habitat Alteration Demand for Wildlife Products Pollution Introduced Species Conserving Biodiversity 1. Strategies for Conservation 2. Challenges in Conservation Species Diversity Section 6-3 Insects 54.4% Protists 4.2% Other Animals 19.7% Plants 18% Fungi 3.4% Go to Section: Bacteria 0.3% Figure 6-16 Biological Magnification of DDT Section 6-3 Magnification of DDT Concentration Fish-Eating Birds 10,000,000 Large Fish 1,000,000 Small Fish 100,000 Zooplankton 10,000 Producers 1000 Water Go to Section: 1 Interest Grabber Section 6-4 How Much Should It Cost? You may have read that when something becomes hard to obtain, its price usually increases. Such is the case for materials like gold and diamonds, which are nonrenewable resources. Using similar thinking, some researchers believe that all the valuable services provided by a healthy ecosystem should be assigned a dollar value. Go to Section: Interest Grabber continued Section 6-4 Rank the following items in order of their importance to you. Then, next to each item, write down how much you would be willing to pay for it. 1. Fresh, clean drinking water 2. Clean air to breathe 3. An endangered plant containing a substance that can cure cancer 4. Gas for your family car Go to Section: Section Outline Section 6-4 6–4 Charting a Course for the Future A. Ozone Depletion B. Global Climate Change 1. Evidence of Global Warming 2. Possible Effects of Global Warming C. The Value of a Healthy Biosphere Go to Section: Sustainable Agriculture Section 6-4 Cover Crops Legumes, grasses, and other cover crops recycle soil nutrients, reduce fertilizer need, and prevent weed growth. Contour Plowing Contour plowing reduces soil erosion from land runoff. On hilly areas, plowing is done across the hill rather than straight up and down. Controlled Grazing By managing graze periods and herd densities, farmers can improve nutrient cycling, increase the effectiveness of precipitation, and increase the carrying capacity of pastures. A B Yr. 1 Yr. 3 oats alfalfa oats alfalfa Go to Section: C Crop Rotation Different crops use and replenish different nutrients. alfalfa By rotating crops, the loss corn alfalfa (plowed in) of important plant nutrients is decreased. corn Yr. 2 Biological Pest Control The use of predators and parasites to control destructive insects minimizes pesticide use as well as crop damage corn Figure 6-22 Ecosystem Services Section 6-4 Solar energy Production of oxygen Storage and recycling of nutrients Regulation of climate Purification of water and air Storage and distribution of fresh water Food production Nursery habits for wildlife Detoxification of human and industrial waste Natural pest and disease control Management of soil erosion and runoff Go to Section: Video How Does Everything Fit? Click the image to play the video segment. Go Online Interactive test Articles on natural resources and pollution For links on sustainable agriculture, go to www.SciLinks.org and enter the Web Code as follows: cbn-2061. For links on biodiversity, go to www.SciLinks.org and enter the Web Code as follows: cbn-2063. For links on global warming, go to www.SciLinks.org and enter the Web Code as follows: cbn-2064. Interest Grabber Answers 1. Choose an animal other than a human and describe at least two ways in which it may change its environment. Sample answers: A beaver both removes wood from a forest and dams a body of water. A dog digs a hole and may damage plants, but also may unearth worms and turn the soil. 2. What events might have led to the changes that occurred in your town or city? Sample answers: increase or decrease in population and industry. 3. What positive effect have humans had on their environment? What negative effect have humans had on their environment? Humans preserve, conserve, and restore the natural environment as well as construct facilities that improve human health. Humans pollute the air, water, and land with materials that can harm humans and other organisms. Interest Grabber Answers 1. Examine the list of natural resources shown below. Then, classify each natural resource as either renewable or nonrenewable. a. Wood b. Fossil fuels c. Aluminum Renewable; new trees can be grown Nonrenewable; once depleted they are gone Nonrenewable; although recyclable, once depleted the resource is gone d. Wool e. Gold Renewable; sheep can grow new fleece Nonrenewable; once gold ores are depleted no more gold can be made 2. Describe the impact that the loss of nonrenewable resources would have on the environment. Sample answers: fossil fuels; limited energy, which impacts on industry, quality of life, economy; gold and aluminum; decrease in components for technology, which also impacts on industry, quality of life, economy. Interest Grabber Answers 1. List three ways in which other organisms have proved to be a benefit to humans. They provide food, medicine, building materials, and clothing. 2. Compare biodiversity with other natural resources, such as wood and fossil fuels. Do you think biodiversity is a renewable or a nonrenewable resource? Explain your answer. Nonrenewable, because once species of organisms are extinct, they cannot be brought back to life by any natural processes. 3. What can be done to preserve the biodiversity of organisms? Students may suggest protecting endangered species and ecosystems. Interest Grabber Answers Rank the following items in order of their importance to you. Then, next to each item, write down how much you would be willing to pay for it. 1. Fresh, clean drinking water 2. Clean air to breathe 3. An endangered plant containing a substance that can cure cancer 4. Gas for your family car Students’ answers will depend on how important the items are to them. 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