biodegradable 239
biodiversity 243
clear-cutting 245
cover 255
desertification 248
economic costs 241
endangered species 262
energy cost 241 		environmental costs 241
extinction 260
habitat management 256
migratory birds 259
natural resources 240
nonrenewable resources 241
patchwork clear-cutting 246
pollution 239 		reforestation 246
renewable resources 241
selective harvesting 246
threatened species 262
wilderness 250

On-line Flashcards
      With satellite technology, we have mastered the ability to see how land is being used . . . right? Take a look at New Study Raises Estimates of Deforestation in Amazon to see if satellite imagery is the only tool that should be used when estimating deforestation.
      No matter what the estimates of deforestation are in China, officials have stated that it is too much. See what has led to this official statement in China Officially Recognizes Link between Deforestation and Summer Flooding.
      Roads are not allowed, but fires are? How do these practices support healthy forest ecosystems? Some critics of land use in wilderness areas find that banning roads and setting intentional fires are ludicrous management practices. Read Cerro Grande Fire Forces Evacuation, Major Fires Expected in Popular Wilderness Area, and Major Initiative Proposed to Protect National Forests to evaluate the reasons why these practices are used.
      Migrating populations offer special challenges to managers attempting to protect the species. Read how biologists are trying to restore a migratory population of waterfowl in Trumpeter Swans Return to Historic Range and Migratory Route. 		      You may not be able to help trumpeter swans return to their birthplace, but you can help migrating songbirds. Check out Why You Should Buy Organic Coffee: It Helps Migratory Birds and Other Forest Species to see how drinking organic coffee can make a difference.
      How can you make a difference when technology is the culprit? Huge numbers of migratory birds are colliding into digital telephone and TV towers. Do you think better publicity would eventually lead to a technical solution for this problem? Aircraft have collision avoidance features; should the communication industry be required to design and implement collision avoidance features on towers? Take a look at Digital Telephone and TV Towers Kill Migratory Birds by the Millions for more information about how the use of modern communications is adversely affecting migrating populations.
Review Questions
  1. Name three ways humans directly alter ecosystems.
  2. Why is the impact of humans greater today than at any time in the past?
  3. Define pollution. Has the definition changed with time?
  4. What are three kinds of costs associated with resource exploitation?
  5. Why is recycling usually more energy efficient than mining new raw materials?
  6. List three problems associated with forest exploitation.

  1. What is desertification? What causes it?
  2. What effects do increased temperature and increased organic matter have on aquatic ecosystems?
  3. List six techniques utilized by wildlife managers.
  4. What special problems are associated with waterfowl management?
  5. What is extinction, and why does it occur?
  6. Why should humans worry about extinction? Do you?
  7. List three actions that can be taken to prevent extinctions.
Critical Thinking Questions
  1. Imagine you are a mining company executive trying to determine the costs of your mining operation. Create a list of your costs. How important are environmental costs to your company? Why?
  2. Logging, mineral extraction, and grazing on federal lands have been subsidized in order to stimulate economic growth and support rural communities. What place should ecological value have in determining the way land is used? Should subsidies be continued? Justify your stand on this issue.
  3. Perhaps 98-99 percent of all species that have ever existed are extinct. Nearly all went extinct long before humans arrived on the scene. Why should we be concerned about extinction of organisms today?
  4. Would you support clearing of forests and plowing of grasslands that have significant ecological importance in order to support agriculture in countries that have significant hunger? Where do you draw the line between preserving ecosystems and human interest?
  1. A Pacific Northwest Native American tribe has been permitted to hunt an endangered whale species to preserve its traditional culture and to uphold its treaty rights. Now there is fear that other countries will hunt the whales, too. Do you think the tribe should be denied its rights? Why, or why not?
  2. Pharmaceutical companies are helping some developing countries preserve their rainforests so these companies can look for organisms with possible pharmacological value. How do you feel about these arrangements? What limits would you place on the pharmaceutical companies, if any? Why?