Concept Mapping
A new learning activity that involves the student in constructing a concept map has been added at the end of each chapter. This activity is designed to help students see how concepts and ideas are related to one another.

Guest Authors
Each Part Opener in this edition features a guest author's essay that describes an environmental issue in the author's own backyard. These essays help point out the different types of concerns developing in various parts of the U.S., and critical thinking questions help illustrate that often, there is no easy solution to these problems.

Over 100 Reviewers
As with previous editions, reviewers' suggestions are incorporated into the text, either through small changes in copy and/or figures to improve clarity and accuracy, or by providing the most up-to-date information available.

Chapter Updates
Several chapters have had major changes in content or emphasis (click here for a detailed list of changes):

• Chapter 1 has expanded coverage on sustainable development and Agenda 21 to provide current information.
• Chapter 2 has a new section entitled "Do We Consume Too Much?" to highlight the economic and ecological impact of consumption.
• Chapter 4 has a completely rewritten section on the scientific method to better describe the process of science.
• Chapter 5 has a new section on genes, populations, and species to help the reader see the connections between these topics.
• Chapter 6 has new material on both Mediterranean and dry tropical forests ecosystems as suggested by reviewers.
• Chapters 7 and 8 have been updated with recent information on human population.
• Chapter 12 has completely revised sections on plantation forestry and aquaculture.
• Chapter 13 has a new section on smart growth that highlights new trends in urban land use planning.
• Chapter 15 has a rewritten section on genetically modified organisms, requested by reviewers.
• Chapter 16 has new information that emphasizes the need for careful management of water resources.
• Chapter 17 has been restructured to reflect current ways of classifying the different kinds of air pollutants.
• Chapter 18 has a new section that better describes the various ways wastes are categorized.
• Chapter 20 includes new material on eco-terrorism.

New Readings
There are many new boxed readings: Gray Whales of Neah Bay, Hydrogen Fuel Cells, Hanford Nuclear Site, Decision-making in Land Use Planning, Industrial Livestock Production, the Nature of Brownfields, Major Environmental and Resource Conservation Legislation, and U.S Environmental Policy.

New Art
There are over 20 new figures and tables, and many other pieces have been revised.