Biology Science for Life

W I T H P H Y S I O L O G Y

Sixth Edition

Colleen BelkU N I V E R S I T Y O F M I N N E S O T A D U L U T H

Virginia Borden MaierS T. J O H N F I S H E R C O L L E G E

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Library of Congress Cataloging-in-Publication Data

Names: Belk, Colleen M, author. | Maier, Virginia Borden, author.Title: Biology : science for life, with physiology / Colleen Belk, University of Minnesota-Duluth, Virginia Borden Maier, St. John Fisher College.Description: Sixth edition. | New York, NY : Pearson, 2018. | Includes index.Identifiers: LCCN 2017043101 | ISBN 9780134555430Subjects: LCSH: Biology. | Physiology.Classification: LCC QH307.2 .B43 2018b | DDC 570.1--dc23 LC record available at https://lccn.loc.gov/2017043101

(Student edition) ISBN 10: 0-134-55543-0 (Student edition) ISBN 13: 978-0-134-55543-0

5 4 3 2 1 16 17 18 19 20www.pearson.com

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iii

Colleen Belk and Virginia Borden Maier collaborated on teaching biology to nonmajors for more than a decade at the University of Minnesota Duluth. This collaboration has continued for an additional decade through Virginia’s move to St. John Fisher College in Rochester, New York, and has been enhanced by their differing but complementary areas of expertise. In addition to the non-majors course, Colleen teaches general biology for majors, genetics, cell biol-ogy, and molecular biology courses. Virginia teaches general biology for majors, evolutionary biology, zoology, plant biology, ecology, and conservation biology courses.

After several somewhat painful attempts at teaching the breadth of biology to nonmajors in a single semester, the two authors came to the conclusion that they needed to find a better way. They realized that their students were more engaged when they understood how biology directly affected their lives. Colleen and Virginia began to structure their lectures around stories they knew would interest students. When they began letting the story drive the science, they immediately noticed a difference in student engagement and willingness to work harder at learning biol-ogy. Not only has this approach increased student understanding, but it has also increased the authors’ enjoyment in teaching the course—presenting students with fascinating stories infused with biological concepts is simply a lot more fun.

About the Authors

iii

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iv

Preface

To the StudentIs it acceptable to clone humans? When does human life begin? What should be done about our warming planet? Who owns living organisms? What are our responsibilities toward endangered species? Having taught this course for nearly 45 combined years, we understand that no amount of knowledge alone will provide satisfactory answers to these questions. Addressing them requires the develop-ment of a scientific literacy that surpasses the rote mem-orization of facts. To make decisions that are individually, socially, and ecologically responsible, you must not only understand some fundamental principles of biology but also be able to use this knowledge as a tool to help you analyze ethical and moral issues involving biology. This is the aim of this textbook.

To help you understand biology and apply your knowl-edge to an ever-expanding suite of issues, we have struc-tured each chapter of Biology: Science for Life with Physiology around a compelling story in which biology plays an inte-gral role. Through the story you not only will learn the relevant biological principles but also will see how science can be used to help answer complex questions. As you learn to apply the strategies modeled by the text, you will also be strengthening your critical thinking skills.

Even though you may not be planning to be a prac-ticing biologist, well-developed critical thinking skills will enable you to make better decisions about issues that affect your own life and form well-reasoned, fact-based opinions about personal, social, and ecological issues.

To the InstructorYou are probably all too aware that teaching nonmajors stu-dents is very different from teaching biology majors. You know that most of these students will never take another formal science course; therefore, your course may be the last chance for these students to appreciate how biology is woven throughout the fabric of their lives and to develop a deep understanding of the process of science. You rec-ognize the importance of engaging nonmajors because you know that these students will one day be voting on issues of scientific importance, holding positions of power in the community, serving on juries, and making health care decisions for themselves and their families. This text is designed to help you reach your goals.

By now, most nonmajors biology instructors are aware that this book differs from other books in that we use a compelling storyline woven throughout the entire text of each chapter to garner student interest. Once we

draw students in, we keep them engaged by returning to the story line again and again until the end of the chap-ter, when students should be able to form their own data-driven opinions about each topic. Storylines are carefully crafted to allow the same depth and breadth of coverage as any other nonmajors biology text.

Our experience has taught us that students will not remember as many facts as we hope they will, but they can and do remember how to apply the scientific method to novel questions involving biology, and they can retain a strong appreciation for how science differs from other methods of understanding the world. To ensure our stu-dents leave our course with the ability to critically eval-uate information they may come across, this text focuses heavily on the process of science, providing opportunities for students to practice applying the scientific method and analyze data at every opportunity.

New to the Sixth EditionThe positive feedback obtained in previous editions assured us that presenting science alongside a story works for students and instructors alike. In the sixth edition, we have added several new features, a new chapter, and sev-eral reorganized chapters. We also updated storylines and continued to improve popular features from previous edi-tions as well as our supplements.

New Features: Got It?, Show You Know, Go Find Out, Make the Connection, and The Big QuestionIn this edition, we have added many active learning fea-tures to help engage student readers. Each text section includes a series of fill-in-the-blank Got It? questions to help students actively assess their content comprehen-sion. The Chapter Review Summary now contains Show You Know questions to make reviewing the summary a more active process for students. Go Find Out includes activities students can perform on their own or in class in groups that challenge them to find information to answer contemporary questions. The Chapter Review ends with a Make the Connection exercise where students draw lines between statements about the storyline and the science in the chapter to help enhance their understanding. Lastly, each chapter ends with The Big Question, a feature that presents a topic, followed by some smaller questions—some answerable by science and some not. Once students determine which of the smaller questions science can

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PREFACE v

answer, data is presented related to one of these questions. Students analyze the data in light of both the smaller question addressed and the big question that headlines the feature.

Revised Unit One Coverage and New ChaptersBecause we have found that our students are interested in their own fertility, we have reorganized the mitosis and meiosis chapter into two separate chapters. Chapter 6 still deals with mitosis and cancer, but a new Chapter 7 now addresses human fertility and reproduction along with meiosis. Chapter 8 discusses Mendelian genetics in a new storyline, addressing the development and use of newborn screening tests. A newly reorganized Chapter 9 uses the storyline of wrongful convictions to help students learn about the inheritance of complex traits such as those used in identification of suspects by witnesses. In addition, the heritability section helps counter the notion that criminals are born not made, and the DNA profiling section explains how positive identification has been used to exonerate many wrongfully convicted individuals.

Updated StorylinesIn addition to the new storylines listed above associated with content revisions, we’ve revised the storylines of some chapters without strongly modifying content. Chapter 5 continues to address photosynthesis within a storyline about global climate change, but is updated to reflect humanity’s response via the Paris Agreement. Our chap-ter on speciation (Chapter 13) still addresses the issue of supposed human races, but now through the lens of swimmer Simone Manuel’s historic gold medal in the 2016 Olympics. The chapter covering climate and biomes (Chapter 17) now addresses the concept of the human “footprint.” Our summary of the respiratory and cardio-vascular systems (Chapter 20) addresses the known and unknown health issues of electronic cigarettes and the

practice of “vaping.” And the spread of Zika virus is now the storyline for Chapter 23, which describes the virus’s effects on reproduction and embryonic development.

Supplements and MediaThe supplements package continues to be updated and expanded by Judi Roux, Ed.D., a talented college instruc-tor with years of classroom experience in nonmajors biol-ogy and colleague of Colleen Belk at the University of Minnesota Duluth. We think you will find that the supple-ments she has developed are brimming with ideas for how to reach this particular population of students. In addition to the Instructor’s Manual (for use in traditional lectures as well as flipped classrooms) and a test bank, we also provide slides, animation, and videos to enrich instruction efforts. Available online, the Biology: Science for Life with Physiology resources are easy to navigate and support a variety of learning and teaching styles. Judi authored not only the Instructor Guide, but also many Mastering Biology Quiz and Test Items and the PowerPoint lectures as well.

New features in Mastering Biology include figure walk-throughs on tough topics, which provide students with the dynamic guidance of the authors to help them solidify their understanding of the concepts within chal-lenging illustrations. Ready-to-Go Teaching Modules for select chapters provide instructors with assignments to use before and after class, as well as in-class activities that use Clickers or Learning Catalytics for assessment. Each Ready-to-Go Teaching Module also includes an Instructor How-To video, in which Colleen and Virginia provide additional background and helpful hints for presenting the content in the context of particular storylines.

We believe you will find that the design and format of this text and its supplements will help you meet the chal-lenge of helping students both succeed in your course and develop science skills—for life.

We look forward to learning about your experience with Biology: Science for Life with Physiology, Sixth Edition.

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vi

Acknowledgments

Reviewers of Previous EditionsDaryl Adams, Minnesota State University, MankatoKaren Aguirre, Clarkson UniversityJoseph Ahlander, Northeastern State UniversityMarcia Anglin, Miami-Dade CollegeJosephine Arogyasami, Southern Virginia UniversitySusan Aronica, Canisius CollegeMary Ashley, University of ChicagoJames S. Backer, Daytona Beach Community CollegeEllen Baker, Santa Monica CollegeGail F. Baker, LaGuardia Community CollegeNeil R. Baker, The Ohio State UniversityAndrew Baldwin, Mesa Community CollegeThomas Balgooyen, San Jose State UniversityTamatha R. Barbeau, Francis Marion UniversitySarah Barlow, Middle Tennessee State UniversityVeronica Barr, Heartland Community CollegeKelly Barry, Southern Illinois State UniversityAndrew M. Barton, University of Maine, FarmingtonKatrinka Bartush, University of North TexasVernon Bauer, Francis Marion UniversityPaul Beardsley, Idaho State UniversityDonna Becker, Northern Michigan UniversityTania Beliz, College of San MateoDavid Belt, Penn Valley Community CollegeDrew Benson, Georgia Gwinnett CollegeSteve Berg, Winona State UniversityCarl T. Bergstrom, University of WashingtonJanet Bester-Meredith, Seattle Pacific UniversityBarry Beutler, College of Eastern UtahWendy Birky, California State University, NorthridgeDonna H. Bivans, Pitt Community CollegeLesley Blair, Oregon State UniversityJohn Blamire, City University of New York, Brooklyn CollegeBarbara Blonder, Flagler CollegeSusan Bornstein-Forst, Marian CollegeBruno Borsari, Winona State UniversityJames Botsford, New Mexico State UniversityAnne Bower, Philadelphia UniversityRobert S. Boyd, Auburn UniversityBryan Brendley, Gannon UniversityEric Brenner, New York UniversityPeggy Brickman, University of GeorgiaCarol Britson, University of MississippiCarole Browne, Wake Forest UniversityNeil Buckley, State University of New York, PlattsburghJamie Burchill, California State University, NorthridgeStephanie Burdett, Brigham Young UniversityWarren Burggren, University of North Texas

ReviewersEach chapter of this book was thoroughly reviewed sev-eral times as it moved through the development process. Reviewers were chosen on the basis of their demonstrated talent and dedication in the classroom. Many of these reviewers are already trying various approaches to actively engage students in lectures and to raise the scientific liter-acy and critical thinking skills among their students. Their passion for teaching and commitment to their students were evident throughout this process. These devoted indi-viduals scrupulously checked each chapter for scientific accuracy, readability, and coverage level.

All of these reviewers provided thoughtful, insight-ful feedback, which improved the text significantly. Their efforts reflect their deep commitment to teaching nonma-jors and improving the scientific literacy of all students. We are very thankful for their contributions.

Reviewers of the Sixth EditionOliver Beckers, Murray State UniversitySwapna Bhat, University of North GeorgiaStephanie Burdett, Brigham Young UniversityMichelle Cawthorn, Georgia Southern UniversityKari Clifton, University of West FloridaRichard Cowart, University of DubuqueBryan Dewsbury, University of Rhode IslandJeanette Gore, University of TampaEileen Gregory, Rollins CollegeJay Hodgson, Armstrong State UniversityBrenda Hunzinger, Lake Land CollegeSarah Krajewski, Grand Rapids Community CollegeKathy Kresge, Northampton Community CollegeDanielle McGrath, San Jacinto CollegeJeanelle Morgan, University of North GeorgiaTyler Olivier, San Jacinto CollegeBrent Palmer, University of KentuckyMonica Parker, Florida State College

at JacksonvilleJill Penn, Georgia Gwinnett CollegeStephen Piccolo, Brigham Young UniversityBenjamin Predmore, University of

South FloridaIsaiah Schauer, Brazosport CollegeChristine Simmons, Southern Illinois University–

EdwardsvilleMarialana Speidel, Jefferson CollegeBishnu Twanabasu, Weatherford CollegeSusan Whittemore, Gaston CollegeHeather Woodson, Gaston College

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ACKNOWLEDGMENTS vii

Stephen Ebbs, Southern Illinois UniversityDouglas Eder, Southern Illinois University, EdwardsvilleSteve Eisenberg, Elizabethtown Community and Technical

CollegePatrick J. Enderle, East Carolina UniversityWilliam Epperly, Robert Morris CollegeAna Escandon, Los Angeles Harbor CollegeDan Eshel, City University of New York, Brooklyn CollegeMarirose Ethington, Genesee Community CollegeDonna Ewing, McLellan Community CollegeDeborah Fahey, Wheaton CollegeChris Farrell, Trevecca Nazarene UniversityMichele Finn, Monroe Community CollegeRichard Firenze, Broome Community CollegeLynn Firestone, Brigham Young UniversitySusan Fisher, Ohio State UniversityBrandon L. Foster, Wake Technical Community CollegeRichard A. Fralick, Plymouth State UniversityBarbara Frank, Idaho State UniversityStewart Frankel, University of HartfordLori Frear, Wake Technical Community CollegeJennifer Fritz, The University of Texas at AustinDavid Froelich, Austin Community CollegeSuzanne Frucht, Northwest Missouri State UniversityEdward Gabriel, Lycoming CollegeAnne Galbraith, University of Wisconsin, La CrossePatrick Galliart, North Iowa Area Community CollegeWendy Garrison, University of MississippiJanet Gaston, Troy UniversityAnthony Gaudin, Ivy Tech Community College of Indiana–

Columbus/FranklinAlexandros Georgakilas, East Carolina UniversityRobert George, University of North Carolina, WilmingtonRichard Gill, Brigham Young UniversityTammy Gillespie, Eastern Arizona CollegeSharon Gilman, Coastal Carolina UniversityMac F. Given, Neumann CollegeBruce Goldman, University of Connecticut, StorrsAndrew Goliszek, North Carolina Agricultural and Technical

State UniversityBeatriz Gonzalez, Santa Fe Community CollegeEugene Goodman, University of Wisconsin, ParksideLara Gossage, Hutchinson Community CollegeRebekka Gougis, Illinois State UniversityTamar Goulet, University of MississippiBecky Graham, University of West AlabamaMary Rose Grant, University of Missouri, St. LouisJohn Green, Nicholls State UniversityRobert S. Greene, Niagara UniversityTony J. Greenfield, Southwest Minnesota State UniversityEileen Gregory, Rollins CollegeBruce Griffis, Kentucky State UniversityMark Grobner, California State University, StanislausMichael Groesbeck, Brigham Young University, IdahoStanley Guffey, University of Tennessee

Rebecca Burton, Alverno CollegeNancy Butler, Kutztown UniversitySuzanne Butler, Miami-Dade Community CollegeWilbert Butler, Tallahassee Community CollegeDavid Byres, Florida State College, JacksonvilleTom Campbell, Pierce College, Los AngelesCassandra Cantrell, Western Kentucky UniversityMerri Casem, California State University, FullertonAnne Casper, Eastern Michigan UniversityDeborah Cato, Wheaton CollegeMichelle Cawthorn, Georgia Southern UniversityPeter Chabora, Queens CollegeBruce Chase, University of Nebraska, OmahaThomas F. Chubb, Villanova UniversityGregory Clark, University of Texas, AustinKimberly Cline-Brown, University of Northern IowaReggie Cobb, Nash Community CollegeMary Colavito, Santa Monica CollegeWilliam H. Coleman, University of HartfordWilliam F. Collins III, Stony Brook UniversityWalter Conley, State University of New York, PotsdamJerry L. Cook, Sam Houston State UniversityMelanie Cook, Tyler Junior CollegeScott Cooper, University of Wisconsin, La CrosseErica Corbett, Southeastern Oklahoma State UniversityGeorge Cornwall, University of ColoradoAngela Costanzo, Hawaii Pacific UniversityCharles Cottingham, Frederick Community CollegeJames B. Courtright, Marquette UniversityRichard Cowart, Coastal Bend Community CollegeAngela Cunningham, Baylor UniversityJudy Dacus, Cedar Valley CollegeJudith D’Aleo, Plymouth State UniversityDeborah Dardis, Southeastern Louisiana UniversityJuville Dario-Becker, Central Virginia Community CollegeGarry Davies, University of Alaska, AnchorageMelissa Deadmond, Truckee Meadows Community CollegeEdward A. DeGrauw, Portland Community CollegeHeather DeHart, Western Kentucky UniversityMiriam del Campo, Miami-Dade Community CollegeVeronique Delesalle, Gettysburg CollegeLisa Delissio, Salem State CollegeBeth De Stasio, Lawrence UniversityElizabeth Desy, Southwest Minnesota State UniversityDonald Deters, Bowling Green State UniversityGregg Dieringer, Northwest Missouri StateDiane Dixon, Southeastern Oklahoma State UniversityChristopher Dobson, Grand Valley State UniversityCecile Dolan, New Hampshire Community Technical

College, ManchesterMatthew Douglas, Grand Rapids Community CollegeLee C. Drickamer, Northern Arizona UniversityDani DuCharme, Waubonsee Community CollegeTcherina Duncombe, Palm Beach Community CollegeSusan Dunford, University of Cincinnati

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viii ACKNOWLEDGMENTS

Mark Hammer, Wayne State UniversityBlanche Haning, North Carolina State UniversityRobert Harms, St. Louis Community CollegeCraig M. Hart, Louisiana State UniversityJay Hatch, University of MinnesotaPatricia Hauslein, St. Cloud State UniversityStephen Hedman, University of Minnesota DuluthBethany Henderson-Dean, University of FindlayJulie Hens, University of Maryland University CollegePeter Heywood, Brown UniversityJulia Hinton, McNeese State UniversityPhyllis C. Hirsh, East Los Angeles CollegeElizabeth Hodgson, York College of PennsylvaniaJay Hodgson, Armstrong Atlantic State UniversityLeland Holland, Pasco-Hernando Community CollegeJane Horlings, Saddleback Community CollegeMargaret Horton, University of North Carolina, GreensboroLaurie Host, Harford Community CollegeDavid Howard, University of Wisconsin, La CrosseMichael Hudecki, State University of New York, BuffaloMichael E. S. Hudspeth, Northern Illinois UniversityLaura Huenneke, New Mexico State UniversityPamela D. Huggins, Fairmont State UniversitySue Hum-Musser, Western Illinois UniversityCarol Hurney, James Madison UniversityJames Hutcheon, Georgia Southern UniversityAnthony Ippolito, DePaul UniversityRichard Jacobson, Laredo Community CollegeMalcolm Jenness, New Mexico Institute of TechnologyCarl Johansson, Fresno City CollegeStaci Johnson, Southern Wesleyan UniversityRon Johnston, Blinn CollegeThomas Jordan, Pima Community CollegeJann Joseph, Grand Valley State UniversityMary K. Kananen, Penn State University, AltoonaArnold Karpoff, University of LouisvilleJudy Kaufman, Monroe Community CollegeMichael Keas, Oklahoma Baptist UniversityJudith Kelly, Henry Ford Community CollegeKaren Kendall-Fite, Columbia State Community CollegeAndrew Keth, Clarion UniversityTrey Kidd, University of Missouri, St. LouisDavid Kirby, American UniversityStacey Kiser, Lane Community CollegeDennis Kitz, Southern Illinois University, EdwardsvilleCarl Kloock, California State, BakersfieldJennifer Knapp, Nashville State Technical Community

CollegeLoren Knapp, University of South CarolinaMichael A. Kotarski, Niagara UniversitySarah Krajewski, Grand Rapids Community CollegeMichelle LaBonte, Framingham State CollegePhyllis Laine, Xavier UniversityDale Lambert, Tarrant County CollegeTom Langen, Clarkson UniversityMichael L’Annunziata, Pima Community College

Lynn Larsen, Portland Community CollegeMark Lavery, Oregon State UniversityBrenda Leady, University of ToledoMary Lehman, Longwood UniversityLorraine Leiser, Southeast Community CollegeDoug Levey, University of FloridaLee Likins, University of Missouri, Kansas CityAbigail Littlefield, Landmark CollegeAndrew D. Lloyd, Delaware State UniversityJayson Lloyd, College of Southern IdahoSuzanne Long, Monroe Community CollegeJudy Lonsdale, Boise State UniversityKate Lormand, Arapahoe Community CollegePaul Lurquin, Washington State UniversityKimberly Lyle-Ippolito, Anderson UniversityDouglas Lyng, Indiana University/Purdue UniversityMichelle Mabry, Davis and Elkins CollegeStephen E. MacAvoy, American UniversityMolly MacLean, University of MaineCharles Mallery, University of MiamiCindy Malone, California State University, NorthridgeMark Manteuffel, St. Louis Community College, Flo ValleyKen Marr Green, River Community CollegeKathleen Marrs, Indiana University/Purdue UniversityRoger Martin, Brigham Young University, Salt Lake CenterMatthew J. Maurer, University of Virginia’s College at WiseGeri Mayer, Florida Atlantic UniversityT. D. Maze, Lander UniversitySteve McCommas, Southern Illinois University, EdwardsvilleColleen McNamara, Albuquerque Technical Vocational

InstituteMary McNamara, Albuquerque Technical Vocational InstituteJohn McWilliams, Oklahoma Baptist UniversitySusan T. Meiers, Western Illinois UniversityDiane Melroy, University of North Carolina, WilmingtonJoseph Mendelson, Utah State UniversityPaige A. Mettler-Cherry, Lindenwood UniversityDebra Meuler, Cardinal Stritch UniversityJames E. Mickle, North Carolina State UniversityCraig Milgrim, Grossmont CollegeHugh Miller, East Tennessee State UniversityJennifer Miskowski, University of Wisconsin, La CrosseAli Mohamed, Virginia State UniversityStephen Molnar, Washington UniversityJames Mone, Millersville UniversityDaniela Monk, Washington State UniversityLinda Moore, Georgia Military CollegeDavid Mork, Yakima Valley Community CollegeBertram Murray, Rutgers UniversityKen Nadler, Michigan State UniversityJohn J. Natalini, Quincy UniversityAlissa A. Neill, University of Rhode IslandDawn Nelson, Community College of Southern NevadaJoseph Newhouse, California University of PennsylvaniaJeffrey Newman, Lycoming CollegeLori Nicholas, New York University

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ACKNOWLEDGMENTS ix

David L.G. Noakes, University of GuelphShawn Nordell, St. Louis UniversityTonye E. Numbere, University of Missouri, RollaJorge Obeso, Miami-Dade College, North CampusErin O’Brien, Dixie CollegeIgor Oksov, Union County CollegeAlex Olvido, University of North GeorgiaJennifer O’Malley, Saint Charles Community CollegeKevin Padian, University of California, BerkeleyArnas Palaima, University of MississippiBrent Palmer, University of KentuckyAnthony Palombella, Longwood UniversityMurali Panen, Luzerne County Community CollegeMonica Parker, Florida State CollegeMarilee Benore Parsons, University of Michigan, DearbornSteven L. Peck, Brigham Young UniversityJavier Penalosa, Buffalo State CollegeMurray Paton Pendarvis, Southeastern Louisiana UniversityShelly Penrod, Lonestar CollegeKrista Peppers, University of Central ArkansasRhoda Perozzi, Virginia Commonwealth UniversityJohn Peters, College of CharlestonPatricia Phelps, Austin Community CollegePolly Phillips, Florida International UniversityIndiren Pillay, Culver-Stockton CollegeFrancis J. Pitocchelli, Saint Anselm CollegeNancy Platt, Pima Community CollegeRoberta L. Pohlman, Wright State UniversityCalvin Porter, Xavier UniversityLinda Potts, University of North Carolina, WilmingtonRobert Pozos, San Diego State UniversityMarion Preest, The Claremont CollegesAnne-Marie Prouty, Sam Houston State UniversityGregory Pryor, Francis Marion UniversityRongsun Pu, Kean UniversityNarayanan Rajendran, Kentucky State UniversityAnne E. Reilly, Florida Atlantic UniversityMichael H. Renfroe, James Madison UniversityLaura Rhoads, State University of New York, PotsdamAshley Rhodes, Kansas State UniversityGwynne S. Rife, University of FindlayTodd Rimkus, Marymount UniversityLaurel Roberts, University of PittsburghWilma Robertson, Boise State UniversityBill Rogers, Ball State UniversityWilliam E. Rogers, Texas A&M UniversityTroy Rohn, Boise State UniversityDeborah Ross, Indiana University/Purdue UniversityChristel Rowe, Hibbing Community CollegeYelena Rudayeva, Palm Beach Community CollegeJoanne Russell, Manchester Community CollegeMichael Rutledge, Middle Tennessee State UniversityWendy Ryan, Kutztown UniversityChristopher Sacchi, Kutztown UniversityKim Sadler, Middle Tennessee State UniversityBrian Sailer, Albuquerque Technical Vocational Institute

Jasmine Saros, University of Wisconsin, La CrosseKen Saville, Albion CollegeMichael Sawey, Texas Christian UniversityLouis Scala, Kutztown UniversityDebbie Scheidemantel, Pima Community CollegeDaniel C. Scheirer, Northeastern UniversityBeverly Schieltz, Wright State UniversityNancy Schmidt, Pima Community CollegeRobert Schoch, Boston UniversityJulie Schroer, Bismarck State CollegeFayla Schwartz, Everett Community CollegeSteven Scott, Merritt CollegeGray Scrimgeour, University of TorontoRoger Seeber, West Liberty State CollegeMary Severinghaus, Parkland CollegeAllison Shearer, Grossmont CollegeRobert Shetlar, Georgia Southern UniversityCara Shillington, Eastern Michigan UniversityJack Shurley, Idaho State UniversityBill Simcik, Lonestar CollegeIndrani Sindhuvalli, Florida State College, JacksonvilleBeatrice Sirakaya, Pennsylvania State UniversityCynthia Sirna, Gadsden State Community CollegeLynnda Skidmore, Wayne County Community CollegeThomas Sluss, Fort Lewis CollegeDouglas Smith, Clarion University of PennsylvaniaMark Smith, Chaffey CollegeBrian Smith Black, Hills State UniversityGregory Smutzer, Temple UniversitySally Sommers, Smith Boston UniversityAnna Bess Sorin, University of MemphisMarialana Spiedel, Jefferson CollegeBryan Spohn Florida, Community College at Jacksonville,

Kent CampusCarol St. Angelo, Hofstra UniversityBrooke Stabler, University of Central OklahomaAmanda Starnes, Emory UniversitySusan L. Steen, Idaho State UniversityTimothy Stewart, Longwood CollegeJennifer Stovall, Southcentral Kentucky Community &

Technical CollegeShawn Stover, Davis and Elkins CollegeBradley J. Swanson, Central Michigan UniversityJoyce Tamashiro, University of Puget SoundJeffrey Taylor, Slippery Rock UniversityMartha Taylor, Cornell UniversityGlena Temple, Viterbo UniversityAlice Templet, Nicholls State UniversityTania Thalkar, Clarion University of PennsylvaniaJeff Thomas, California State University, NorthridgeJeffrey Thomas, University of California, Los AngelesJanis Thompson, Lorain County Community CollegeNina Thumser, California University of PennsylvaniaAlana Tibbets, Southern Illinois University, EdwardsvilleMartin Tracey, Florida International UniversitySue Trammell, John A. Logan College

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x ACKNOWLEDGMENTS

Jeffrey Travis, State University of New York, AlbanyMichael Troyan, Pennsylvania State UniversityRobert Turgeon, Cornell UniversityKimberly Turk, Caldwell Community CollegeMichael Tveten, Pima Community College, Northwest

CampusJames Urban, Kansas State UniversityBrandi Van Roo, Framingham State CollegeJohn Vaughan, St. Petersburg Junior CollegeMartin Vaughan, Indiana State UniversityMark Venable, Appalachian State UniversityPaul Verrell, Washington State UniversityTanya Vickers, University of UtahJanet Vigna, Grand Valley State UniversitySean Walker, California State University, FullertonDon Waller, University of Wisconsin, MadisonSandra Walsh, The CitadelMark Walvoord, University of OklahomaTracy Ware, Salem State CollegeJennifer Warner, University of North Carolina, CharlotteCarol Weaver, Union UniversityFrances Weaver, Widener UniversityDerek Weber, Raritan Valley Community CollegeElizabeth Welnhofer, Canisius CollegeMarcia Wendeln, Wright State UniversityMichael Wenzel, Folsom Lake CollegeShauna Weyrauch, Ohio State University, NewarkWayne Whaley, Utah Valley State CollegeHoward Whiteman, Murray State UniversityJennifer Wiatrowski, Pasco-Hernando Community CollegeVernon Wiersema, Houston Community CollegeGerald Wilcox, Potomac State CollegePeter J. Wilkin, Purdue University North CentralHeather Wilson-Ashworth, Utah Valley University

Robert R. Wise, University of Wisconsin, OshkoshMichelle Withers, Louisiana State UniversityArt Woods, University of Texas, AustinElton Woodward, Daytona Beach Community CollegeKenneth Wunch, Sam Houston State UniversityDonna Young, University of WinnipegMichelle L. Zjhra, Georgia Southern UniversityJohn Zook, Ohio UniversityMichelle Zurawski, Moraine Valley Community College

The Book TeamThe sixth edition has been energized by the work and ideas of our new editor Cady Owens. She has brought a fresh and insightful perspective that is much appreciated by both authors. We remain indebted to our editor for the previous three editions, Star MacKenzie, who was instrumental in helping us develop the revision plan for this edition. Our development editor for much of the sixth edition, Deb-bie Hardin, played a key role in shaping new and heavily revised chapters. Her talented successor, Evelyn Dahlgren, has drawn on her extensive experience to further improve the final product. We are also grateful for the steady hand of the Director of Courseware Portfolio Management Beth Wilbur, who is always thoughtful, responsive, and support-ive of us and this project. We continue to feel fortunate to work with such a talented and devoted team.

This book is dedicated to our families, friends, and colleagues who have supported us over the years. Having loving families, great friends, and a supportive work envi-ronment has enabled us to make this heartfelt contribution to nonmajors biology education.

Colleen Belk Virginia Borden Maier

“Because science, told as a story, can intrigue and inform the non-scientific minds among us, it has the potential to bridge the two cultures into which civilization is split—the sciences and the humanities. For educators, stories are an exciting way to draw young minds into the scientific culture.”

—E. O. Wilson

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Contents

C H A P T E R 1 Can Science Cure the Common Cold? 2Introduction to the Scientific Method 21.1 The Process of Science 3

The Nature of Hypotheses 3Scientific Theories 4The Logic of Hypothesis Tests 5

1.2 Hypothesis Testing 7The Experimental Method 9Controlled Experiments 9Minimizing Bias in Experimental Design 11Using Correlation to Test Hypotheses 12

1.3 Understanding Statistics 16What Statistical Tests Can Tell Us 16Factors that Influence Statistical Significance 17What Statistical Tests Cannot Tell Us 19

1.4 Evaluating Scientific Information 20Primary Sources 20Information from Anecdotes 21Science in the News 21Understanding Science from Secondary Sources 22Is There a Cure for the Common Cold? 23

Sounds Right, But Is It? 24THE BIG QUESTION How do I know what to believe? 24Chapter Review 26

U N I T O N E

Chemistry and Cells

C H A P T E R 2 Science Fiction, Bad Science, and Pseudoscience 30Water, Biochemistry, and Cells 302.1 A Definition of Life 31

2.2 The Properties of Water 32The Structure of Water 32Water Is a Good Solvent 33Water Facilitates Chemical Reactions 34Water Moderates Temperature 34The Drinking-Water Hypothesis Requires

More Substantiation 34

2.3 Chemistry for Biology Students 35Chemical Bonds 35The Bermuda Triangle Revisited 36

2.4 Biological Macromolecules 37Carbohydrates 37Proteins 38Lipids 38Nucleic Acids 39Dietary Macromolecules and Behavior 41

2.5 An Introduction to Evolutionary Theory 42

Sounds Right, But Is It? 44THE BIG QUESTION Does balanced reporting help us draw more accurate conclusions? 44Chapter Review 46

C H A P T E R 3 Is It Possible to Supplement Your Way to Better Performance and Health? 49Nutrients and Membrane Transport 493.1 Nutrients 50

Macronutrients 50Micronutrients 53Antioxidants 56

3.2 Cell Structure 57Plasma Membrane 57Subcellular Structures 58

3.3 Transport Across Membranes 61Passive Transport: Diffusion, Facilitated Diffusion,

and Osmosis 62Active Transport: Pumping Substances across

the Membrane 62

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U N I T T W O

Genetics

C H A P T E R 6 Cancer 107DNA Synthesis and Mitosis 1076.1 What Is Cancer? 108

Tumors Can Be Cancerous 108Risk Factors for Cancer 108

6.2 Passing Genes and Chromosomes to Daughter Cells 110Genes and Chromosomes 111DNA Replication 111

6.3 The Cell Cycle and Mitosis 113Interphase 113Mitosis 114Cytokinesis 116

6.4 Cancer Prevention, Detection, and Treatment 117Tumor Suppressors Help Prevent Cancer 117Cancer Detection 118Cancer Treatment 119

Sounds Right, But Is It? 120THE BIG QUESTION Can I prevent myself from getting cancer? 120Chapter Review 121

C H A P T E R 7 Fertility 124Meiosis and Human Reproduction 1247.1 Producing Sperm and Eggs: Meiosis 125

Interphase 127

Exocytosis and Endocytosis: Movement of Large Molecules across the Membrane 63

Sounds Right, But Is It? 64THE BIG QUESTION Should I routinely use detox products? 65Chapter Review 66

C H A P T E R 4 Body Weight and Health 69Enzymes, Metabolism, and Cellular Respiration 694.1 Enzymes and Metabolism 70

Enzymes 70Metabolism 71

4.2 Cellular Respiration 72Structure and Function of ATP 72Cellular Respiration 74Stages of Cellular Respiration 75Metabolism of Other Nutrients 77Metabolism without Oxygen: Anaerobic Respiration

and Fermentation 78

4.3 Body Weight and Health 78Body Mass Index 79Underweight Is Unhealthy 79

Sounds Right, But Is It? 81THE BIG QUESTION How unhealthy is anorexia? 82Chapter Review 83

C H A P T E R 5 Life in the Greenhouse 86Photosynthesis and Climate Change 865.1 The Greenhouse Effect 87

Earth Is a Greenhouse 87Water, Heat, and Temperature 88

5.2 The Flow of Carbon 90

5.3 Can Photosynthesis Slow Down Global Climate Change? 93Chloroplasts: The Site of Photosynthesis 93The Process of Photosynthesis 94

5.4 How High Temperatures Might Reduce Photosynthesis 97

5.5 How We Can Slow Global Climate Change 99

Sounds Right, But Is It? 102THE BIG QUESTION Should global warming be kept below 4°C? 102Chapter Review 103

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CONTENTS xiii

Meiosis I 127Meiosis II 129

7.2 Problems with Meiosis and Lowered Fertility 131

7.3 Bringing Sperm and Egg Together 132Male Reproductive Anatomy 132Female Reproductive Anatomy 134

Sounds Right, But Is It? 137THE BIG QUESTION Does marijuana use impair fertility? 137Chapter Review 138

C H A P T E R 8 Does Testing Save Lives? 141Mendelian Genetics 1418.1 The Inheritance of Traits 142

Genes and Chromosomes 143Producing Diversity in Offspring 144

8.2 Basic Mendelian Genetics: When the Role of Genes Is Clear 148Genotype and Phenotype 149Genetic Diseases in Humans 150Using Punnett Squares to Predict Offspring

Genotypes 152

8.3 Extensions of Mendelian Genetics 155

8.4 Sex and Inheritance 157Sex Determination and X-Linkage 157Pedigrees 158

Sounds Right, But Is It? 161THE BIG QUESTION Should there be universal screening for killer diseases? 161Chapter Review 162

C H A P T E R 9 Biology of Wrongful Convictions 166Complex Genetic Traits, Heritability, and DNA Profiling 1669.1 Eyewitness Testimony and Complex

Genetic Traits 167Polygenic Traits 167Quantitative Traits 168

9.2 Genes, Criminality, and Implicit Bias 170Studying Nature versus Nurture 170The Use and Misuse of Heritability 172Implicit Bias 175

9.3 Positive Identification 176DNA Profiling 176Polymerase Chain Reaction 176

Sounds Right, But Is It? 178The Big Question Should the death penalty be abolished in the United States? 179Chapter Review 180

C H A P T E R 10 Genetically Modified Organisms 183Gene Expression, Mutation, Stem Cells, and Cloning 18310.1 Protein Synthesis and Gene Expression 184

From Gene to Protein 184Transcription 186Translation 186Mutations 190Gene Expression 191

10.2 Producing Recombinant Proteins 192Cloning a Gene Using Bacteria 192FDA Regulations 194

10.3 Genetically Modified Plants and Animals 194Modifying Crop Plants 195Modifying Animals 196Gene Editing Using CRISPR in Plants

and Animals 197

10.4 Genetically Modified Humans 198Stem Cells 198Gene Therapy 199Gene Editing in Humans 200Cloning Humans 200

Sounds Right, But Is It? 201THE BIG QUESTION Should anti-GMO activists give up the fight? 202Chapter Review 203

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U N I T T H R E E

Evolution

C H A P T E R 11 Where Did We Come From? 206The Evidence for Evolution 20611.1 What Is Evolution? 207

The Process of Evolution 207The Theory of Evolution 208

11.2 Charles Darwin and the Theory of Evolution 210Early Views of Evolution 210The Voyage of the Beagle 211Developing the Hypothesis of Common

Descent 212Alternative Ideas on the Origins and Relationships

among Organisms 213

11.3 Examining the Evidence for Common Descent 215Linnaean Classification 215Anatomical Homology 218Developmental Homologies 219Molecular Homology 220Biogeography 222The Fossil Record 223

11.4 Are Alternatives to the Theory of Evolution Equally Valid? 228Weighing the Alternatives 231The Best Scientific Explanation for the Diversity

of Life 231

Sounds Right, But Is It? 232THE BIG QUESTION Should high school biology teachers be required to “teach the controversy”? 233Chapter Review 234

C H A P T E R 12 An Evolving Enemy 238Natural Selection 23812.1 Return of a Killer 239

What Is Tuberculosis? 239Treatment—and Treatment Failure 240

12.2 Natural Selection Causes Evolution 241Darwin’s Observations 242Darwin’s Inference: Natural Selection

Causes Evolution 245Testing Natural Selection 245

12.3 Natural Selection Since Darwin 248The Modern Synthesis 248The Subtleties of Natural Selection 249Patterns of Selection 250

12.4 Natural Selection and Human Health 252Tuberculosis Fits Darwin’s Observations 252Selecting for Drug Resistance 253Stopping Drug Resistance 254Can Natural Selection Save Us from

Superbugs? 255

Sounds Right, But Is It? 257THE BIG QUESTION Should I stop purchasing meats that are raised using antibiotics? 257Chapter Review 259

C H A P T E R 13 Understanding Race 262Speciation and Macroevolution 26213.1 What Is a Species? 263

The Biological Species Concept 263Speciation 266Isolation and Divergence of Gene Pools 266The Evolution of Reproductive Isolation 268

13.2 Are Human Races Biological? 270The History of Human Races 271The Morphological Species Concept 271Modern Humans: A History 272Genetic Evidence of Divergence 273Human Races Are Not Isolated Biological Groups 274Human Races Have Never Been Truly Isolated 277

13.3 Why Human Groups Differ 278Natural Selection 278Convergent Evolution 279Genetic Drift 281Sexual Selection 283Assortative Mating 284

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CONTENTS xv

Sounds Right, But Is It? 285THE BIG QUESTION Are affirmative action policies that favor black students applying for college admission good public policy? 286Chapter Review 287

C H A P T E R 14 The Greatest Species on Earth? 291Biodiversity and Classification 29114.1 Biological Classification 292

How Many Species Exist? 292Domains of Life 294

14.2 The Diversity of Life 298The Domains Bacteria and

Archaea 298The Origin of the Domain

Eukarya 300The Protista 301Kingdom Animalia 302Kingdom Fungi 307Kingdom Plantae 310Not Quite Living: Viruses 313

14.3 Learning about Species 314Reconstructing Evolutionary History 314The Greatest Species on Earth 316

Sounds Right, But Is It? 317THE BIG QUESTION Should lab mice and rats have the same rights as other nonhuman animals? 318Chapter Review 319

U N I T F O U R

Ecology

C H A P T E R 15 Is the Human Population Too Large? 323Population Ecology 32315.1 Population Growth 324

Population Structure 324Exponential Population Growth 325The Demographic Transition 327

15.2 Limits to Population Growth 328Carrying Capacity and Logistic

Growth 329Earth’s Carrying Capacity for Humans 330

15.3 The Future of the Human Population 332A Possible Population Crash? 333Avoiding Disaster 334

Sounds Right, But Is It? 336THE BIG QUESTION Should the international community continue to provide food aid to populations experiencing food crises? 337Chapter Review 338

C H A P T E R 16 Conserving Biodiversity 341Community and Ecosystem Ecology 34116.1 The Sixth Extinction 342

Measuring Extinction Rates 342Causes of Extinction 344

16.2 The Consequences of Extinction 350Loss of Resources 350Predation, Mutualism, and Competition 351Energy and Chemical Flows 357Psychological Effects 359

16.3 Saving Species 360Protecting Habitat 360Small Populations Are Vulnerable 362Conservation Genetics 363Protecting Biodiversity versus Meeting

Human Needs 366

Sounds Right, But Is It? 368THE BIG QUESTION Is wind power good or bad for birds? 368Chapter Review 370

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C H A P T E R 17 The Human Footprint 373Climate and Biomes 37317.1 Climate Determines Habitability 374

Global Temperature and Precipitation Patterns 376Local Influences on Climate 378

17.2 Terrestrial Biomes and the Human Footprint 380Tundra 383Desert 383Forests and Shrublands 384Grasslands 387

17.3 Aquatic Biomes and the Human Footprint 388Freshwater 388Saltwater 391

Sounds Right, But Is It? 395THE BIG QUESTION Can my actions make a difference on global environmental issues? 395Chapter Review 397

U N I T F I V E

Animal Structure and Function

C H A P T E R 18 Organ Donation 400Tissues and Organs 40018.1 Tissues 401

Epithelial Tissue 401Connective Tissue 402Muscle Tissue 404Nervous Tissue 405Tissue Donation 406

18.2 Organs and Organ Systems 407

18.3 Regulating the Internal Environment 410Negative Feedback 410Positive Feedback 410Growing and Printing Replacement Organs 411Organ Donation Saves Lives 412

Sounds Right, But Is It? 413THE BIG QUESTION Should kidney donors be financially compensated? 414Chapter Review 415

C H A P T E R 19 Binge Drinking 418The Digestive and Urinary Systems 41819.1 The Digestive System 419

Mechanical and Chemical Breakdown of Food 419

Absorption of Digested Foods 422Regulation of Digestive Secretions 423

19.2 Removing Toxins from the Body: The Urinary System 423Kidney Structure and Function 423Engaging Safely with Alcohol 426

Sounds Right, But Is It? 428THE BIG QUESTION Does alcohol make men more likely to commit sexual assault? 428Chapter Review 430

C H A P T E R 20 Clearing the Air 432Respiratory and Cardiovascular Systems 43220.1 Effects of Smoke on the Respiratory

System 433What Happens When You Take a Breath? 435Gas Exchange 437The Role of Hemoglobin in Gas Exchange 438Smoke Particles and Lung Function 438

20.2 Spreading the Effects of Smoke: The Cardiovascular System 440Structure of the Cardiovascular System 441Movement of Materials through the Cardiovascular

System 445Smoke and Cardiovascular Disease 447The Precautionary Principle in Public Health 448

Sounds Right, But Is It? 449The Big Question Should marijuana be legalized? 450Chapter Review 451

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CONTENTS xvii

C H A P T E R 21 Vaccination: Protection and Prevention or Peril? 454Immune System, Bacteria, Viruses, and Other Pathogens 45421.1 Infectious Agents 455

Bacteria 455Viruses 458Eukaryotic Pathogens 461

21.2 The Body’s Response to Infection: The Immune System 462First Line of Defense: Skin and Mucous

Membranes 462Second Line of Defense: Phagocytes and

Macrophages, Inflammation, Defensive Proteins, and Fever 463

Third Line of Defense: Lymphocytes 464Cell-Mediated and Antibody-Mediated

Immunity 467

Sounds Right, But Is It? 469THE BIG QUESTION Why are females vaccinated against human papilloma virus more often than males? 470Chapter Review 471

C H A P T E R 22 Human Sex Differences 474Endocrine, Skeletal, and Muscular Systems 47422.1 The Endocrine System 475

Hormones 475Endocrine Glands 476

22.2 The Skeletal System 478Bone Structure and Remodeling 479Sex Differences in Bone Structure 480

22.3 The Muscular System 482Muscle Structure and Contraction 482Muscle Interaction with Bones 484Sex Differences in Muscle 484

22.4 Other Biology-Based Sex Differences 484

Sounds Right, But Is It? 486THE BIG QUESTION Is sex selection an acceptable practice? 487Chapter Review 488

C H A P T E R 23 Zika in Pregnancy 491Developmental Biology, Menstruation, Birth Control, and Pregnancy 49123.1 Early Development 492

Fertilization 492Embryonic Development 493Development of the Brain When Zika

Is Present 494

23.2 Avoiding or Delaying Pregnancy 495The Menstrual Cycle 495Birth Control Methods 496

23.3 Pregnancy and Childbirth 501

Sounds Right, But Is It? 503THE BIG QUESTION When does human life begin? 504Chapter Review 505

C H A P T E R 24 Study Drugs: Brain Boost or Brain Drain? 508Brain Structure and Function 50824.1 The Nervous System 509

Central and Peripheral Nervous Systems 509The Senses 510Amphetamines Effects 512

24.2 The Human Brain 514Cerebrum 515Thalamus and Hypothalamus 515Cerebellum and Brain Stem 516

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24.3 Neurons 517Neuron Structure and Function 517Nonmedical Use of ADD Medications 520Consequences of Using Nonprescribed ADD

Medications 521

Sounds Right, But Is It? 524THE BIG QUESTION Is drug addiction a disease of the brain? 524Chapter Review 526

U N I T S I X

Plant Biology

C H A P T E R 25 Feeding the World 529Plant Structure and Growth 52925.1 Plants as Food 530

The Evolution of Agriculture: Food Plant Diversity 530

Plant Structure 532Plant Reproduction 534

25.2 Plant Growth Requirements 538How Plants Grow 538Maximizing Plant Growth: Water, Nutrients,

and Pest Control 541Designing Better Plants: Hybrids and Genetic

Engineering 547

25.3 The Future of Agriculture 548Modern Agriculture Causes Environmental

Damage 548How to Reduce the Damage 551

Sounds Right, But Is It? 556THE BIG QUESTION Should I purchase organically grown foods? 556Chapter Review 558

C H A P T E R 26 Growing a Green Thumb 561Plant Physiology 56126.1 The Right Plant for the Place:

Water Relations 562

Transpiration 562Adaptations That Affect Transpiration 564Water Inside Plant Cells 567

26.2 A Beautiful Garden: Translocation and Photoperiodism 569Translocation of Sugars and Nutrients 569Managing Translocation 570Photoperiodism 571

26.3 Pleasing Forms: Tropisms and Hormones 574Tropisms 574Hormones 575We Are All Gardeners 576

Sounds Right, But Is It? 577THE BIG QUESTION Should I rip out my lawn? 578Chapter Review 579

Appendix: Metric System Conversions A-1Answers ANS-1Glossary G-1Credits C-1Index I-1

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