Integrated Principles of Zoology is a college text adaptable to any introductory course in zoology. This eleventh edition, as with previous editions, describes the diversity of animal life and the fascinating adaptations that enable animals to inhabit nearly all conceivable ecological niches. We retain in this revision the basic organization of the 10^th edition and its distinctive features, especially emphasis on the principles of evolution and zoological science. Also retained are several pedagogical features that have made previous editions easily accessible to students: opening chapter dialogues drawn from the chapter's theme; chapter summaries and review questions to aid student comprehension and study; accurate and visually appealing illustrations; in-text derivations of generic names; chapter notes and essays that enhance the text by offering interesting sidelights to the narrative; and an extensive glossary providing pronunciation, derivation, and definition of terms used in the text.

Many of the changes in this edition were guided by the suggestions of more than 60 zoology instructors who read and commented on sections of the 10^th edition. In addition, the vertebrate chapters of Part Three, and several chapters on functional systems (Part Four) were revised by invited Contributors, all experienced zoologists who were solicited for their interest and expertise in the subject matter of specific chapters. In general, all chapters were revised to make the text current while eliminating excessive detail, and to place more emphasis on experimentation and comparative studies in zoology.

• Separate treatments of the origin of life and chemistry of life are condensed into a single chapter (Chapter 2), thus streamlining the presentation by discussing basic chemistry in the context of origin of life.
• The order of chapters in Part Two is altered to offer a better study sequence for students, providing a grounding in genetics and evolutionary theory before undertaking the chapters on reproduction and development. There are numerous places in the development chapter in which an understanding of genetics is crucial.
• A completely new chapter on immunology (Chapter 37) was developed, covering both vertebrate and invertebrate immunology and embracing many new discoveries in this fast-moving field.

• Throughout the text we updated references, revised or replaced many illustrations, and rewrote many of the Review Questions to provoke thought and reduce emphasis on rote memorization.
• Suggested Internet topics are added at the end of each chapter.
• The end paper on Origin of Life and Geologic Time Table has been replaced with a revised version in full color.

The principal revisions are explained below.

• Chapters 2 (Chemistry) and 3 (Origin of Life) now form an integrated review of the kinds of organic molecules found in living systems and their origins in the earth's primitive reducing atmosphere. A review of basic chemistry (atoms, elements, and molecules; bonding theory; acids, bases, salts, and buffers) is available for reference.
• For Chapter 3, on cells as units of life, we revised the discussion of cell structure and cell junctions, and reorganized the sequence of certain topics. Several illustrations in this and the following chapter on cellular metabolism were redrawn for this edition.

• Chapter 5, Principles of Genetics, features a revised section on molecular genetics, adding a new coverage of genomics, and a new subsection on molecular systematics. The increasing ease with which genes can be sequenced and compared to sequences of the same gene in other taxa has led to a great many revisions of phylogenies based on sequence analysis. Such findings have made necessary many changes in the diversity chapters in Part Three of this book.
• Chapter 7, The Reproductive Process, was revised to clarify relationships among bisexual reproduction, hermaphroditism, and parthenogenesis. A new section on sex determination summarizes the most recent understanding of the male determining gene and masculinizing hormones, and discovery of the Sex Reversing X region on the X chromosome and its role in promoting ovary formation. The final section on endocrine events that orchestrate reproduction was rewritten and updated.
• Chapter 8, Principles of Development, was extensively revised in both text and line art. The order in which material on cleavage is presented was reorganized to clarify relationships among principal topics of yolk amount and distribution, cleavage type, cleavage pattern, and subtopics of direct and indirect development, mosaic vs. regulative development, and differences between protostomes and deuterostomes. Cleavage of centrolecithal eggs was added. The section on gastrulation now compares the process in sea stars, reptiles, birds, and mammals. Among other sections revised and updated were those on cytoplasmic specification and homeotic genes.

• Chapter 9 provides a concise presentation on animal architecture as an introduction to animal diversity, which is the core of most zoology courses. Several sections of this chapter were revised: complexity and body size, muscular tissue, animal body plans, body cavities, and terminology used in specifying aspects of symmetry.
• Chapter 10, Classification and Phylogeny of Animals, explains the principles of animal taxonomy and how they are applied by the competing schools of evolutionary taxonomy and cladistics. Because classification pervades every course in zoology, students should understand that systematics provides the evolutionary basis for zoological study. Changes include revision of systematics of great apes to use a cladistic classification, and updating of the material on classification of the Bilateria to incorporate results of new molecular phylogenetic studies.
• The title of Chapter 11 was changed from "The Animal-like Protista" to "Protozoan Groups." Although both Protozoa and Protista no longer are considered valid taxa, we continue to use the terms "protozoa" and "protozoan" informally to distinguish these animal-like phyla. Among sections revised in the protozoan chapter are pseudopodial movement, mechanism of contractile vacuole action, and the final sections on phylogeny and classification.
• For Chapter 12 (Mesozoa and Parazoa) we revised the sections on origin and phylogeny of Metazoa, and deleted reference to class Sclerospongiae, which is no longer recognized as a valid taxon.
• We made several changes in Chapters 14 and 15 on acoelomate and pseudocoelomate animals, including reorganization of the material on class Turbellaria, and revision of the phylogeny sections for both chapters. There is evidence now that acoels (order Acoela) are not flatworms but form the sister group for all other Bilateria. All remaining acoelomates are now placed in the newly erected protostome superphylum Lophotrochozoa.
• Each of the pseudocoelomate phyla are assigned to either Lophotrochozoa or to the alternative superphylum Ecdysozoa. Phylogeny sections for mollusc, annelid, and arthropod chapters also were revised to embrace new information from sequence analysis, which places Mollusca and Annelida in superphylum Lophotrochozoa, and Arthropoda in superphylum Ecdysozoa. We point out, however, that analysis upon which the Lophotrochozoa/Ecdysozoa hypothesis is based fails to support monophyly of Mollusca and Annelida. Nevertheless, few if any zoologists believe molluscs and annelids are not monophyletic groups.
• In Chapter 20, on terrestrial mandibulates, we introduce the term parasitoid and emphasize the importance of parasitoids in controlling populations of other insects. Among other changes in this chapter we strengthened coverage of pheromones, including use of pheromone baits in insect traps and importance of such use in monitoring insects of economic importance.
• Lophophorate animals (Chapter 22) are now assigned to Protostomia, forming an important group in superphylum Lophotrochozoa. If lophophorates are protostomes as most recent evidence suggests, the trimerous coelomic arrangement must have evolved independently in protostomes and deuterostomes.
• Chapter 25 (chordates) received minor revision, including reworking sections on ancestry and evolution, chordate fossil discoveries, and position of amphioxus in speculations on chordate ancestry.
• Chapter 26 on fishes was extensively revised. With Osteichthyes no longer considered a valid taxon, Actinopterygii and Sarcopterygii are elevated to class; this change is accompanied by a discussion of the origin and radiation of ray-finned fishes, radiation of the neopterygians, and morphological trends that permitted great diversification of the teleosts. Introductory sections on ancestry, relationships, and biology of fishes were rewritten to clarify relationships among major fish groups. Revisions in the section on sharks include discussions of sensory systems, shark attacks, and reproduction. Several changes were made in the art program, including corrections in synapomorphies in the cladogram of fishes.
• The title of Chapter 28 was changed to Reptilian Groups to emphasize paraphyly in class Reptilia. Topics revised in this chapter include lung breathing in turtles, viviparity, and characteristics that distinguish reptiles from amphibians.
• In the bird chapter (Chapter 29) we added a note on recent fossil bird discoveries, and revised discussions of skeletal weight comparisons in birds and mammals, bird kidney function, and sun-azimuth orientation of bird migration. We reorganized the treatment of forms of bird wings for flight and added a new illustration to show hovering flight in hummingbirds.
• Chapter 30, Mammals, includes an updated discussion of the first hominids to summarize recent fossil finds, and a revised illustration of hominid skulls. Other changes: adoption of a cladistic classification for primates, and revision of discussions of horns and antlers, glands, feeding specializations, body weight and food consumption, and reproductive patterns.

• The revisions for Chapter 31, Support, Protection, and Movement include discussions of skin cancer from sunlight, mechanisms of ciliary movement, energy for muscle contraction, fast and slow fibers, and description of dermal derivative in vertebrates.
• Chapter 32, Homeostasis was updated throughout. Treatments revised include hyperosmotic regulation in invertebrates, hypoosmotic regulation in fishes, shark kidney function, mechanism of contractile vacuole function, and glomerular filtration.
• A major improvement in flow and unity of Chapter 33, Internal Fluids, was transfer of defense mechanisms and immunity to a separate chapter (Chapter 37).
• Chapter 34, Digestion and Nutrition, includes a discussion on nutritional requirements to embrace new understanding of relationships among the hunger center, brown fat, the protein thermogenin, and the recently discovered hormone leptin. We also updated statistics on world meat consumption, malnutrition, and world population. The discussion on gastrointestinal hormones, previously included in the endocrine chapter, was moved to this chapter.
• The chapter on nervous coordination (Chapter 35) was revised throughout. The most important revisions appear in sections dealing with nature of the nerve impulse, synapses, evolution of invertebrate nervous systems, reflex acts and reflex arcs, autonomic nervous systems, odor reception, and color vision.
• Chapter 36, Chemical Coordination, features an updated section on second messenger system, and new sections that describe the role of growth hormone as a diabetogenic hormone, and action of the most recently discovered hormone, leptin, in regulating eating behavior and energy balance.
• Chapter 27, Immunity, is NEW and covers the topics of susceptibility and resistance, innate defense mechanisms, acquired immune response in vertebrates, blood group antigens, and immunity in invertebrates. The section on acquired immune response in vertebrates includes descriptions of self-non self discrimination (MHC proteins), recognition molecules (antibodies and T-cell receptors), cytokines, humoral response (T_H2 arm), and cell-mediated response (T_H1 arm).
• Chapter 38 concludes this unit with a discussion of animal behavior. It features an expanded explanation of the ritualization of behavior, and new sections on diversity of mating systems, altruistic behavior and kin selection, and animal cognition. The latter describing the remarkable studies of the Gardners with the chimpanzee Washoe, and Pepperberg's work with an African grey parrot.

• Chapter 39, Biosphere and Animal Distribution, includes an updated discussion of the proposed effect of carbon dioxide on the earth's climate. It also provides an expanded explanation of the earth's heat engine with accompanying new art, and added mean annual temperature and rainfall values to all biome descriptions.
• Chapter 40, Animal Ecology, was completely rewritten to provide much greater emphasis on populational and community ecology. It features expanded explanations of niche, characteristics of population (age structure, growth rates, survivorship), population regulation, and interactions among populations in communities.

To help students in vocabulary development, as in previous editions we have boldfaced key words, and provided the derivations of technical and zoological terms, and generic names of animals where they first appear in the text. In this way students gradually become familiar with the more common roots that comprise many technical terms. An extensive glossary of almost 1,100 terms provides pronunciation, derivation, and definition of each term. Many new terms were added to the glossary or rewritten for this edition.

A distinctive feature of this text is a chapter prologue for each chapter that draws out some theme or fact relating to the subject of the chapter. Some present biological, particularly evolutionary, principles; others (especially those in the survey sections) illuminate distinguishing characteristics of the group treated in the chapter. Each is intended to present an important concept drawn from the chapter in an interesting manner that will facilitate learning by students, as well as engage their interest and pique their curiosity.

Chapter notes, which appear throughout the book, augment the text material and offer interesting sidelights without interrupting the narrative. We prepared many new notes for this edition and revised several of the existing notes.

To assist students in chapter review, each chapter ends with a concise summary, a list of review questions, and annotated selected references. The review questions enable the student to self-test retention and understanding of the more important chapter material.

The historical appendix, unique to this textbook, lists key discoveries in zoology, and separately describes books and publications that have greatly influenced the development of zoology. Many readers have found this appendix an invaluable reference to be consulted long after their formal training in zoology.

Again, William C. Ober and Claire W. Garrison have enhanced the art program for this text with many new full color paintings that replace older art, or that illustrate new material. Bill's artistic skills, knowledge of biology, and experience gained from an earlier career as a practicing physician, have enriched this text through seven of its editions. Claire practiced pediatric and obstetric nursing before turning to scientific illustration as a full-time career. Texts illustrated by Bill and Claire have received national recognition and won awards from the Association of Medical Illustrators, American Institute of Graphic Arts, Chicago Book Clinic, Printing Industries of America, and Bookbuilders West. They are also recipients of the Art Directors Award.

The Instructor's Manual and Test Item File provides annotated chapter outlines, chapter-specific changes for this edition, lecture enrichment suggestions, commentaries and lesson plans, questions for advanced classes, and a listing of resource references for each chapter. Also included is a listing of transparencies and slides available with the book, and a comprehensive test bank offering 35-50 objective questions per chapter. We trust this will be of particular value to first-time users of the text, although experienced teachers may also find much of value.

The Laboratory Manual by Cleveland P. Hickman, Jr., Frances M. Hickman, and Lee Kats, Laboratory Studies in Integrated Principles of Zoology, now in its tenth edition, can be adapted conveniently for two semester, one semester, or term courses by judicious selection of exercises. Test questions contained in the Instructor's Manual and Test File are also available as a Computerized Test Bank, a test generation system for IBM and Macintosh computers. Using this system, instructors can create tests or quizzes quickly and easily. Questions can be sorted by type or level of difficulty, and instructors also can add their own material to the bank of questions provided.

A set of 150 full color transparency acetates of important textual illustrations are available with this edition of Integrated Principles of Zoology. Labeling is clear, dark, and bold for easy reading.

A set of 148 animal diversity slides, photographed by the authors and Bill Ober on their various excursions, are offered in this unique textbook supplement. Both invertebrates and vertebrates are represented. Descriptions, including specific names of each animal and brief overview of the animal's ecology and/or behavior, accompany the slides.

A Zoology Visual Resource Library CD-ROM containing 1,000 line drawings and photos, is now available to instructors to enhance lecture presentations.

A tutorial CD-ROM, the Essential Study Partner, will be available soon to aid students in their study of zoology.

An Online Learning Center web site is available with this edition, and contains additional readings, animations, quizzing, key term flashcards, and much more. Check it out at www.mhhe.com/zoology.

By the end of 2000, this text will also be available in a CD-ROM format, complete with hyperlinks to the Online Learning Center, an interactive glossary, and animations.

We wish to thank the following zoologists who were engaged by McGraw-Hill to contribute directly to the revision of specific chapters. These persons, and the chapters to which they contributed, are:

Sylvester Allred, Northern Arizona University

Chapter 30 Mammals

Andrew Blaustein, Oregon State University

Chapter 38 Animal Behavior

David Eisenhour, Morehead State University

Chapter 26 Fishes

Helen I'Anson, Washington and Lee University

Chapter 7 The Reproductive Process

Chapter 35 Nervous Coordination

Chapter 36 Chemical Coordination

Lawrence E. Hurd, Washington and Lee University

Chapter 40 Animal Ecology

Sharyn Marks, Humboldt State University

Chapter 8 Principles of Development

Ron Myers, Weber State University

Chapter 28 Reptiles

Chapter 31 Support, Protection, and Movement

Bruce Wunder, Colorado State University

Chapter 29 Birds

The authors extend their warmest thanks to reviewers who suggested numerous improvements and whose collective wisdom was of the greatest assistance to us as we approached this edition. Their experience with students of varying backgrounds, and their interest in and knowledge of the subject, helped to shape the text into its final form.

Barbara J. Abraham

Hampton University

Felix Akojie

Paducah Community College

David Bass

University of Central Oklahoma

R. P. Benard

American International College

Gerald Bergman

Northwest State College

Patricia M. Biesiot

University of Southern Mississippi

Del Blackburn

Clark College

Marilyn S. Branton

Stillman College

Kimberly "Rusty" Brown

Mississippi Gulf Coast Community College, Jackson County Campus

Bruce R. Burnham

United States Air Force Academy

Paul J. Bybee

Utah Valley State College

Suzzette F. Chopin

Texas A&M University

Phillip D. Clem

University of Charleston

Mariette S. Cole

Concordia University

Sarah Cooper

Beaver College

Michael Craig

Central College

John R. Crooks

Iowa Wesleyan College

David Cunnington

North Idaho College

Charles Dailey

Sierra College

Aaron R. Davis

East Central Community College

Armando A. de la Cruz

Mississippi State University

Lorri Dennis

Alfred State College

Elizabeth A. Desy

Southwest State University

Elizabeth Drumm

Oakland Community College

Peter Ducey

State University of New York-Cortland

David J. Eisenhour

Morehead State University

Carl D. Frailey

Johnson County Community College

Sandi B. Gardner

Triton College

Glenn A. Gorelick

Citrus College

Angela Harper-English

Hinds Community College

John C. Hurd

LaGrange College

Jeffrey Jack

Western Kentucky University

Suzanne Kempke

Armstrong Atlantic State University

Robert L. Koenig

Southwest Texas Junior College

Marian G. Langer

St. Francis College

Larry N. Latson

Lipscomb University

Elizabeth L. Lucyszyn

Medaille College

Kevin Lyon

Jones County Junior College

Kathleen M. Marr

Lakeland College

Deborah A. Martin

University of Georgia

Matthew D. Moran

Hendrix College

Charles M. Page

El Camino College

Robert Powell

Avila College

Arthur G. Raske

NBBC

Vaughn M. Rundquist

Montana State University-Northern

Allen F. Sanborn

Barry University

Neil B. Schanker

College Of The Siskiyous

Fred H. Schindler

Indian Hills Community College

Cheryl A. Schmidt

Central Missouri State University

John Richard Schrock

Emporia State University

John G. Shiber

University of Kentucky-PCC

Walter M. Shriner

Denison University

Richard Sims

Jones County Junior College

W. David Sissom

West Texas A&M University

Stewart Skeate

Lees-McRae College

Robert George Sprackland

College of Notre Dame

Sarah H. Swain

Middle Tennessee State University

Elizabeth Waldorf

Mississippi Gulf Coast Community College, Jeff Davis Campus

Catherine Wilcoxson

Northern Arizona University

Mary Leslie Burns Wilson

Gordon College

H. Patrick Woolley

East Central College

Eugene A. Young

Southwestern College

David D. Zeigler

University of North Carolina-Pembroke

Craig A. Zimmerman

Aurora University

Brenda Zink

Northeasten Junior College

The authors express their appreciation to the editors and support staff at McGraw-Hill Higher Education who made this project possible. Special thanks are due Marge Kemp, Sponsoring Editor, and Donna Nemmers, Developmental Editor, who were the driving forces in piloting this text throughout its development. Joyce Berendes, Project Manager, somehow kept authors, text, art, and production programs on schedule. Others who played key roles and to whom we express our gratitude are Bea Sussman, who copy-edited the manuscript; John Leland and Jodi Banowetz who oversaw the extensive photographic and art programs, respectively. The text was designed by Stuart Paterson. We are indebted to them for their talents and dedication.

Although we make every effort to bring to you an error-free text, errors of many kinds inevitably find their way into a textbook of this scope and complexity. We will be grateful to readers who have comments or suggestions concerning content to send their remarks to Donna Nemmers, Developmental Editor, 2460 Kerper Boulevard, Dubuque, IA 52001.

Cleveland P. Hickman, Jr.

Larry S. Roberts

Allan Larson