Biology

rav88132_fm_i-xxiv.indd 1 11/25/15 12:26 AM Eleventh Edition Biology Kenneth A. Mason University of Iowa Jonathan B. Losos Harvard University Susan R. Singer Carleton College Contributors: Shelley Jansky University of Wisconsin – Madison Tod Duncan University of Colorado Denver Based on the work of Peter H. Raven President Emeritus, Missouri Botanical Garden; George Engelmann Professor of Botany Emeritus, Washington University George B. Johnson Professor Emeritus of Biology, Washington University rav88132_fm_i-xxiv.indd 1 11/25/15 12:26 AM BIOLOGY, ELEVENTH EDITION Published by McGraw-Hill Education, 2 Penn Plaza, New York, NY 10121. Copyright © 2017 by McGraw-Hill Education. All rights reserved. Printed in the United States of America. Previous editions © 2014, 2011, and 2008. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of McGraw-Hill Education, including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning. Some ancillaries, including electronic and print components, may not be available to customers outside the United States. This book is printed on acid-free paper. 1 2 3 4 5 6 7 8 9 0 DOW/DOW 1 0 9 8 7 6 ISBN 978-1-259-18813-8 MHID 1-259-18813-2 Senior Vice President, Products & Markets: Kurt L. Strand Vice President, General Manager, Products & Markets: Marty Lange Vice President, Content Design & Delivery: Kimberly Meriwether David Managing Director: Michael Hackett Brand Manager: Justin Wyatt Director, Product Development: Rose Koos Product Developer: Elizabeth Sievers Marketing Manager: Patrick Reidy Director of Digital Content: Michael G. Koot, PhD Digital Product Analyst: Christine Carolson Director, Content Design & Delivery: Linda Avenarius Program Manager: Angela R. FitzPatrick Content Project Managers: April R. Southwood/Brent dela Cruz Buyer: Jennifer Pickel Design: David W. Hash Content Licensing Specialists: Lori Hancock/Lorraine Buczek Cover Image: Red Kite (Milvus milvus) © Moment/Getty Images/RF; male peacock tail feather (Pavo cristatus) © Darrell Gulin/The Image Bank/Getty Images; flat faced longhorn beetle of family Cerambidae © Javier Torrent/VWPics/Getty Images; cross section of an alfalfa stem © Biologyimaging.com; model of DNA molecules © Doug Struthers/The Image Bank/Getty Images Compositor: MPS Limited Printer: R. R. Donnelley All credits appearing on page or at the end of the book are considered to be an extension of the copyright page. Library of Congress Cataloging-in-Publication Data Mason, Kenneth A., author. | Raven, Peter H. B iology / Kenneth A. Mason, University of Iowa, Jonathan B. Losos, Harvard University, Susan R. Singer, Carleton College; contributors, Shelley Jansky, University of Wisconsin / Madison, Tod Duncan, University of Colorado Denver. E leventh edition. | New York, NY : McGraw-Hill Education, 2016. | “Based on the work of Peter H. Raven, President Emeritus, Missouri Botanical Garden; George Engelmann, Professor of Botany Emeritus, Washington University, George B. Johnson, Professor Emeritus of Biology, Washington University.” LCCN 2015045817 | ISBN 9781259188138 (alk. paper) LCSH: Biology—Textbooks. L CC QH308.2 .R38 2016 | DDC 570—dc23 LC record available at http://lccn.loc.gov/2015045817 The Internet addresses listed in the text were accurate at the time of publication. The inclusion of a website does not indicate an endorsement by the authors or McGraw-Hill Education, and McGraw-Hill Education does not guarantee the accuracy of the information presented at these sites. mheducation.com/highered rav88132_fm_i-xxiv.indd 2 11/25/15 12:26 AM Brief Contents Committed to Excellence v 28 Prokaryotes 544 Preparing Students for the Future ix 29 Protists 565 30 Seedless Plants 588 Using Connect® and Biology, 11th edition xii 31 Seed Plants 602 Contents xviii 32 Fungi 619 33 Animal Diversity and the Evolution of Body Plans 638 Part The Molecular Basis of Life 1 34 Protostomes 660 I 35 Deuterostomes 692 1 The Science of Biology 1 2 The Nature of Molecules and the Properties of Water 17 Part Plant Form and Function 732 3 The Chemical Building Blocks of Life 33 VI 36 Plant Form 732 Part Biology of the Cell 59 37 Transport in Plants 757 II 38 Plant Nutrition and Soils 775 4 Cell Structure 59 39 Plant Defense Responses 792 5 Membranes 88 40 Sensory Systems in Plants 804 6 Energy and Metabolism 107 41 Plant Reproduction 831 7 How Cells Harvest Energy 122 8 Photosynthesis 147 Part Animal Form and Function 864 9 Cel Communication 168 VII 10 How Cells Divide 186 42 The Animal Body and Principles of Regulation 864 Part Genetic and Molecular Biology 207 43 The Nervous System 888 III 44 Sensory Systems 916 11 Sexual Reproduction and Meiosis 207 45 The Endocrine System 939 12 Patterns of Inheritance 221 46 The Musculoskeletal System 963 13 Chromosomes, Mapping, and the Meiosis–Inheritance 47 The Digestive System 983 Connection 239 48 The Respiratory System 1003 14 DNA: The Genetic Material 256 49 The Circulatory System 1020 15 Genes and How They Work 278 50 Osmotic Regulation and the Urinary System 1040 16 Control of Gene Expression 304 51 The Immune System 1057 17 Biotechnology 327 52 The Reproductive System 1086 18 Genomics 353 53 Animal Development 1107 19 Cellular Mechanisms of Development 375 Part Ecology and Behavior 1134 VIII Part Evolution 399 IV 54 Behavioral Biology 1134 20 Genes Within Populations 399 55 Ecology of Individuals and Populations 1164 21 The Evidence for Evolution 421 56 Community Ecology 1187 22 The Origin of Species 440 57 Dynamics of Ecosystems 1209 23 Systematics, Phylogenies, and Comparative Biology 460 58 The Biosphere 1232 24 Genome Evolution 480 59 Conservation Biology 1259 25 Evolution of Development 497 Appendix A-1 Part Diversity of Life on Earth 513 V Glossary G-1 26 The Origin and Diversity of Life 513 Credits C-1 27 Viruses 527 Index I-1 iii rav88132_fm_i-xxiv.indd 3 11/25/15 12:26 AM About the Authors North?eld, Minnesota, where she has taught introductory biology, plant biology, genetics, and plant development for nearly 30 years. Her research focuses on the development and evolution of ?owering plants and genomics learning. Singer has authored numerous scienti?c publications on plant development and coauthored education reports including Vision and Change and “America’s Lab Report.” A fellow of the American Association for the Advancement of Science (AAAS), she has received the American Society of Plant Biology’s Excellence in Teaching Award and the Botanical Society’s Bessey Award, served on the National Acad- emies Board on Science Education, and chaired several National Research Council study committees including the committee that Pictured left to right: Susan Rundell Singer, Jonathan Losos, produced Discipline-Based Education Research. Kenneth Mason Lead Digital Author Kenneth Mason is currently associated with the University of Iowa, Ian Quitadamo is a Professor with a Department of Biology. His academic positions, as a teacher and dual appointment in Biological Sciences researcher, include the faculty of the University of Kansas, where he and Science Education at Central designed and established the genetics lab, and taught and pub- Washington University in Ellensburg, lished on the genetics of pigmentation in amphibians. At Purdue WA. He teaches introductory and majors University, he successfully developed and grew large introductory biology courses and cell biology, biology courses and collaborated with other faculty in an innovative genetics, and biotechnology as well as biology, chemistry, and physics course supported by the National science teaching methods courses for Science Foundation. At the University of Iowa, where his wife served future science teachers and interdisciplinary content courses in as president of the university, he taught introductory biology and alternative energy and sustainability. Dr. Quitadamo was educated at human genetics for eight years. His honor society memberships Washington State University and holds a bachelor’s degree in biology, include Phi Sigma, Alpha Lambda Delta, and, by vote of Purdue master’s degree in genetics and cell biology, and an interdisciplinary pharmacy students, Phi Eta Sigma Freshman Honors Society. Ph.D. in science, education, and technology. Previously a researcher Jonathan Losos is the Monique and Philip Lehner Professor for the of tumor angiogenesis, he now investigates the behavioral and Study of Latin America in the Department of Organismic and neurocognitive basis of critical thinking and has published numerous Evolutionary Biology and curator of herpetology at the Museum studies of factors that improve student critical-thinking performance. of Comparative Zoology at Harvard University. Losos’s research has He has received the Crystal Apple award for teaching excellence and focused on studying patterns of adaptive radiation and evolutionary led multiple initiatives in critical thinking and assessment. He is active diversi?cation in lizards. He is the recipient of several awards, nationally in helping transform university faculty practices. He is a including the prestigious Theodosius Dobzhanksy and David Starr coauthor of Biology, 11th ed., by Mader and Windelspecht (2013), and Jordan Prizes, the Edward Osborne Wilson Naturalist Award, and the is the lead digital author for Biology, 3rd and 4th ed., by Brooker (2014 Daniel Giraud Elliot Medal from the National Academy of Sciences. and 2017), Biology, 10th ed., by Raven (2014), Understanding Biology Losos has published more than 150 scienti?c articles. by Mason (2015), and Principles of Biology by Brooker (2015), all Susan Rundell Singer is the Laurence McKinley Gould Professor of published by McGraw-Hill. For fun, Dr. Quitadamo practices Kyokushin Natural Sciences in the Department of Biology at Carleton College in full contact karate and is a 5th degree blackbelt. iv rav88132_fm_i-xxiv.indd 4 11/25/15 12:26 AM Committed to Excellence With the new 11th edition, Raven and Johnson’s Biology con- accurate context, historical perspective, and relevant supporting de- tinues the momentum built over the last three editions. This tails essential to a modern understanding of life science. edition provides an unmatched comprehensive text fully inte- As the pace of scientific discovery continues to provide new grated with a continually evolving, state-of-the-art digital envi- insights into the foundation of life on Earth, our author team will ronment. We have used this digital environment in the revision continue to use every means possible to ensure students are as pre- of Biology. The McGraw-Hill SmartBook© for the 10th edition pared as possible to engage in biological topics. Our goal now, as provided data on student responses, and thus identify material it has always been, is to ensure student success. To that end, we that students find difficult. This “heat-mapping” technology is approached this revision differently. To help guide our revision for unique in the industry, and allows us to direct editing to diffi- this 11th edition, we were able to incorporate student usage data cult areas, or problem areas for students. The text continues to and input, derived from thousands of our SmartBook® users. be a leader with an organization that emphasizes important bio- SmartBook “heat maps” provided a quick visual snapshot of chap- logical concepts, while keeping the student engaged with learn- ter usage data and the relative difficulty students experienced in ing outcomes that allow assessment of progress in understanding mastering the content. With these data, we were able to hone not these concepts. An inquiry-based approach with robust, adap- only our text content but also the SmartBook probes. tive tools for discovery and assessment in both text and digital resources provides the intellectual challenge needed to promote ? If the data indicated that the subject was more difficult than student critical thinking and ensure academic success. A major other parts of the chapter, as evidenced by a high proportion strength of both text and digital resources is assessment across of students responding incorrectly to the probes, we revised multiple levels of Bloom’s taxonomy that develops critical- or reorganized the content to be as clear and illustrative as thinking and problem-solving skills in addition to comprehen- possible. sive factual knowledge. McGraw-Hill’s Connect® platform ? In other cases, if one or more of the SmartBook probes for a offers a powerful suite of online tools that are linked to the text section was not as clear as it might be or did not appropriately and now include new quantitative assessment tools. The adap- reflect the content, we edited the probe, rather than the text. tive learning system helps students learn faster, study efficient- Below is an example of one of the heat maps from Chapter 8. ly, and retain more knowledge of key concepts. The color-coding in highlighted sections indicate the various levels The 11th edition continues our tradition of providing the of difficulty students experienced in learning the material; topics student with clear learning paths that emphasize data analysis and highlighted in red being the most challenging for students. quantitative reasoning. Additional embedded eBook resources link to asides that delve more deeply into quantitative aspects. As a team, we continually strive to improve the text by inte- grating the latest cognitive and best practices research with methods that are known to positively affect learning. We have multiple fea- tures that are focused on scientific inquiry, including an increased quantitative emphasis in the Scientific Thinking figures. We con- tinue to use the concise, accessible, and engaging writing style of past editions while maintaining the clear emphasis on evolution and scientific inquiry that have made this a leading textbook of choice for majors biology students. Our emphasis on evolution combined with integrated cell and molecular biology and genomics offers our readers a student-friendly text that is modern and well balanced. The 11th edition continues to employ the aesthetically stunning art program that the Raven and Johnson Biology text is known for. Complex topics are represented clearly and succinctly, helping stu- We’re excited about the 11th edition of this quality textbook dents to build the mental models needed to understanding biology. providing a learning path for a new generation of students. All of us Insights into the diversity of life that are provided by molecular have extensive experience teaching undergraduate biology, and we’ve tools have led to a continued updating of these topics in the 11th edi- used this knowledge as a guide in producing a text that is up to date, tion. The diversity unit reflects the most current research on eukary- beautifully illustrated, and pedagogically sound for the student. We’ve otic phylogenies, blending molecular, morphological, and development also worked to provide clear explicit learning outcomes, and more viewpoints. The biotechnology and genomics chapters have been closely integrate the text with its media support materials to provide completely revised to reflect changes in these fast-moving areas of instructors with an excellent complement to their teaching. modern biology. These are just a few examples of the many changes in the 11th edition of Biology that provide students with scientifically Ken Mason, Jonathan Losos, Susan Rundell Singer v rav88132_fm_i-xxiv.indd 5 11/25/15 12:26 AM include the addition of new comparative discussions on the Cutting Edge Science human, wheat, and cancer genome projects. Also, a new Changes to the 11th Edition analytical commentary on the ENCODE project helps students Part I: The Molecular Basis of Life think critically about recent findings in the genomics field. The The revision for the 11th edition started with the end users—the addition of a section on the applications of genomics helps students. As described earlier, the authors analyzed SmartBook students appreciate the social relevance of an often abstract student usage data collected over the life of the 10th edition. The subject area. data from SmartBook revealed content areas where students Part IV: Evolution struggled and based on that information, the authors revised the text to improve clarity. All chapters were evaluated using the Chapter 20—The section on genetic variation was substantially SmartBook heat-mapping data. revised to include recent genomic surveys quantifying the extent Other content-specific changes incude: of genetic variation across the genome in humans. The text was clarified to say that “dominant” has no connotation of selective Part II: Biology of the Cell superiority. In addition, revisions were made to the information Chapter 5—New information on how phospholipid composi- on the current cost in human lives of evolutionary change in tion differs in different membranes and how this can affect microbes evolving resistance to antibiotics. function was added. The chapter was reorganized and a new Chapter 21—The coverage of Darwin’s finches and the figure was added to highlight this material. peppered moth stories were revised to incorporate new informa- Chapter 6—Figures 6.4 and 6.5 were revised for clarity and tion. A section on dating of fossils using radioactive decay was accuracy. added. Chapter 9—A new evolutionary aside on the Ras superfamily Chapter 22—New additions include examples of geographic of small GTPases was added. variation in the black rat snake incorporating recent phylogenetic analyses of DNA data; reproductive character displacement Part III: Genetic and Molecular Biology involving Phlox plants in Texas; and adaptive radiation in plants The overall organization of this section remains the same. We using the Hawaiian Lobelia. The phylogeny of Darwin’s finches have retained the split of transmission genetics into two chapters was modified based on current research. New data appear on the as it has proved successful for students. evolution of developmental regulation of beak shape in Darwin’s Content changes in the molecular genetics portion of this sec- finches, along with a new section on mass extinction. tion continue to update material that is the most rapidly changing Chapter 23—A new section was added on the relationship in the entire book. We also continue to refine the idea that RNA between phylogenetics and taxonomic classifications. The plays a much greater role now than appreciated in the past. figures illustrating how phylogenetics works and how character Chapter 14—Extensive editing for clarity was done based on evolution is interpreted on an evolutionary tree were revised. heat-map data. New data are included on the evolution of saber-teeth in Chapter 15—Extensive updating was done, including a rewritten mammals. section on eukaryotic transcription that emphasizes a more modern Chapter 24—Updates include new data on comparative perspective. Extensive editing throughout the chapter for clarity was genomics. Consideration of primate genomes is expanded, done based on heat-map data. including human and Neanderthal. Chapter 16—Extensive updating was done, including a rewrit- Chapter 25—The introduction was rewritten. The cichlid and ten section on eukaryotic chromatin structure to emphasize a stickleback examples were updated with new information. more modern view, taking new high-throughput data into account. Part V: Diversity of Life on Earth Chapter 17—The chapter was significantly revised to reflect Chapter 26—The information on geological dating and advances in molecular biology techniques such as quantitative taxonomic classification was moved to other chapters where the reverse-transcription PCR, the CRISPR/Cas9 and related gene- discussions were more relevant. editing technologies, and genetic engineering approaches. Additional modifications include the revision or addition of relevant, engaging Chapter 27—This chapter was extensively revised and updated, applications of biotechnology such as wastewater treatment, biofuel including a new section on giant viruses and material on the production, and disease detection and treatment. recent Ebola outbreak in Africa. Chapter 18—Changes to this chapter focus on updating content Chapter 28—Extensive updates include a new section on related to recent advances in sequencing technologies and CRISPR systems, which provide adaptive immunity in bacteria. vi Committed To Excellence rav88132_fm_i-xxiv.indd 6 11/25/15 12:26 AM Chapter 29—Updated discussions appear on microfossils, malaria differences between angiosperms and gymnosperms are vaccines, micronucleus, and Chlamydomonas genome. Changes in emphasized. Distinctions between similar structures in section headings more clearly describe section contents. Numerous different tissues—for example, pits in xylem versus pores in figures were updated to reflect changes in the text. phloem—are made. Chapters 30—The introduction has been modified to provide an Chapter 37—The significance of water potential gradients in overview of land plant evolution. Major trends in the evolution of water transport is clarified and emphasized. The association land plants are now emphasized. The discussion on the effects of between anaerobic conditions and poor root growth is described. mutations on diploid versus haploid bodies has been clarified. The Chapter 38—The mechanism of closing in the Venus flytrap difference between animal and plant life cycles has been empha- leaf has been updated. sized. Throughout the chapter, distinctions between sporophyte and gametophyte generations are clearly described. The signifi- Chapter 41—The concept of alternation of generations has been cance of hornworts in land plant evolution is described. Section clarified and emphasized. headings were changed to more clearly describe section contents. Part VII: Animal Form and Function Chapter 31—The reduction in the complexity of the gameto- Chapter 46—A new illustration of hinge joints was added. phyte generation in the evolution of land plants is emphasized. Chapter 47—The section on pancreas function was revised. Distinctions between gamete and gametophyte, male and female gametophyte, zygote and embryo, and gymnosperms and Chapter 48—Information on cutaneous respiration in turtles angiosperms have been clarified. A discussion of the hypothesis was added. The discussion of gas exchange in the capillaries for the rapid expansion of the world’s biomes by the angio- was revised. sperms has been added. The development of the female gameto- Chapter 49—The illustration and explanation of components of phyte has been described in more detail. The significance of blood cells were revised, along with the explanation of how double fertilization has been described. blood clotting works. Chapter 32—The development of hyphae during the evolution Chapter 52—New information on facultative parthenogenesis of fungi is described. The significance of above-ground spore in vertebrates was added. Information on birth control was dispersal structures is emphasized. The characteristics of each updated. fungus group are clearly and concisely described. The signifi- cance of fungi in rumen biology has been described. Section Part VIII: Ecology and Behavior headings were changed to more clearly describe section contents. Chapter 54—Information on the social behaviors and brains of Numerous figures were updated to reflect changes in the text. prairie and montane voles was updated. The discussion of Chapters 33–35—These chapters have been streamlined, orientation and migration, plus the section on evolution of mate eliminating extraneous information that was outside the scope choice in frogs were revised. Extraneous examples were of the main topics in the chapters. Throughout, changes were eliminated to streamline the chapter. made in the species used as illustrative examples. Information Chapter 55—The information on human population growth and on number of species in different taxa was updated. population demographics for several countries was updated Chapter 34—The information on medical infection rates to using current statistics. various invertebrate groups was updated. Chapter 56— Extraneous material was removed to streamline Chapter 35—The phylogeny of chordates was updated. A the chapter. discussion of evolution of tortoises and new information on the Chapter 57—Figures and explanations of trophic cascades, sensory abilities of the platypus were added. The phylogeny of how effects move from one level of the food web to the next, primates was updated. New information was added on the and the discussions of trophic levels and island biogeography genome of Neanderthals and understanding of the evolution of were revised. New ideas are presented on why the tropics are so modern humans. biologically rich. Part VI: Plant Form and Function Chapter 58—Up-to-date information appears on global Throughout the plant chapters, corrections have been made so warming and global ozone levels, with an illustration of how the that 2n and n refer to the sporophyte and gametophyte genera- Earth revolves around the sun. A section was added on new tions, respectively, and x refers to the number of sets of human diseases that come from animals (zoonotic diseases). chromosomes. Chapter 59—Information on human population growth in Chapter 36—The anatomical positions of components of biodiversity hot spots, human health toll of West Nile Virus, plant tissues are more clearly presented. Structural and the recovery of the peregrine falcon was updated. Committed To Excellence vii rav88132_fm_i-xxiv.indd 7 11/25/15 12:26 AM and many more people behind the scenes have all contributed to the A Note From the Authors success of our text. This includes the digital team, whom we owe a A revision of this scope relies on the talents and efforts of many great deal for their efforts to continue improving our Connect people working behind the scenes and we have benefited greatly assessment tools. from their assistance. Throughout this edition we have had the support of spouses and Beatrice Sussman was the copyeditor for this edition. She has children, who have seen less of us than they might have liked be- labored many hours and always improves the clarity and consis- cause of the pressures of getting this revision completed. They tency of the text. She has made significant contributions to the have adapted to the many hours this book draws us away from quality of the final product. them, and, even more than us, looked forward to its completion. We were fortunate to work again with MPS to update the art In the end, the people we owe the most are the generations of program and improve the layout of the pages. Our close collabo- students who have used the many editions of this text. They have ration resulted in a text that is pedagogically effective as well as taught us at least as much as we have taught them, and their ques- more beautiful than any other biology text on the market. tions and suggestions continue to improve the text and supple- We have the continued support of an excellent team at McGraw- mentary materials. Hill. Justin Wyatt, preceded by Rebecca Olson, the brand managers Finally, we need to thank instructors from across the country for Biology have been steady leaders during a time of change. Lead who are continually sharing their knowledge and experience with Product Developer Liz Sievers, provided support in so many ways us through market feedback and symposia. The feedback we re- it would be impossible to name them all. April Southwood, content ceived shaped this edition. All of these people took time to share project manager, and David Hash, designer, ensured our text was on their ideas and opinions to help us build a better edition of time and elegantly designed. Patrick Reidy, executive marketing Biology for the next generation of introductory biology students, manager, is always a sounding board for more than just marketing, and they have our heartfelt thanks. viii Committed To Excellence rav88132_fm_i-xxiv.indd 8 11/25/15 12:26 AM Preparing Students for the Future Developing Critical Thinking with the Help of . . . Detailed Feedback in Connect® learning, where each step models and reinforces the learning Learning is a process of iterative development, of making process. mistakes, reflecting, and adjusting over time. The question and The feedback for each higher level Blooms question test banks in Connect® for Biology, 11th edition, are more than (Apply, Analyze, Evaluate) follows a similar process: Clarify direct assessments; they are self-contained learning experi- Question, Gather Content, Choose Answer, Reflect on Process. ences that systematically build student learning over time. Unpacking the Concepts For many students, choosing the right answer is not We’ve taken problem solving a step further. In each chapter, necessarily based on applying content correctly; it is more a three to five higher level Blooms questions in the question and matter of increasing their statistical odds of guessing. A major test banks are broken out by the steps of the detailed feedback. fault with this approach is students don’t learn how to process Rather than leaving it up to the student to work through the the questions correctly, mostly because they are repeating and detailed feedback, a second version of the question is presented reinforcing their mistakes rather than reflecting and learning in a stepwise format. Following the problem-solving steps, from them. To help students develop problem-solving skills, all students need to answer questions about earlier steps, such as higher level Blooms questions in Connect are supported with “What is the key concept addressed by the question?” before hints, to help students focus on important information for proceeding to answer the question. A professor can choose answering the questions, and detailed feedback that walks which version of the question to include in the assignment based students through the problem-solving process, using Socratic on the problem-solving skills of the students. questions in a decision-tree-style framework to scaffold ix rav88132_fm_i-xxiv.indd 9 11/25/15 12:26 AM