 |  An Introduction to Biological Evolution Kenneth Kardong,
Washington State University---Pullman
Book PrefaceI wrote this book for a general college audience, as an introduction to the principles and significance of Darwinian evolution. As the book unfolds, the student will meet intellectual challenges; visit the richness of evolutionary science today; explore evolution's insights in biodiversity, mass extinctions, and modern diseases; and examine his/her current and precarious place in nature. This textbook is intended to be the centerpiece of an evolution or evolution-based course, around which the instructor can build a course that suits his/her interests, and focuses on the students. To do so, this textbook departs in three fundamental ways from most other textbooks on evolution:General College Audience
First, this book is intended for a general college audience, especially for students early in their studies. Over the last two decades, I have taught such a course for biology and for non-biology majors. It is surprising to me how even biology majors, with a substantial number of life science courses behind them, are still inept at discussing or using basic evolutionary concepts. The words are right, but a true understanding of evolutionary principles is missing. With some small effort, these students can spout dates, names, and jargon and even some genetic laws they have memorized. But the basic grasp of scientific reasoning and an ability to think critically lags substantially.
States are evaluating their K-12 school curricula, and times are changing. I hope for the better. But for the moment, students still largely learn about evolution from the pulpit and from pop culture. The misunderstandings they bring to the subject of evolution are the same fundamental misunderstandings they harbor about science in general. We can parade the facts before them, but the intellectual equipment students use to think critically about a subject must be developed as well. For many students, the process of evolution is still mysterious, even threatening. Most students who enter college have at least heard of evolution's offense to religious beliefs, but not of its service in unifying all of the modern life sciences. This book is intended for just such an audience.Intellectual Significance
Second, this book departs from others in that it examines the intellectual significance of Darwinian evolution. Darwin's ideas on biological evolution touch every aspect of modern life, from genetic engineering to human medicine. This book explores the history of his thought; the evidence for his ideas, and the implications these have for the appearance and loss of life on Earth; and the significance to our own future as a species.
To begin, students need to be unburdened of the major misconceptions about evolution. At least in my course, they all want to be Lamarckians. Most students think that need drives change, progressively on to better and better organisms. Certainly, Lamarck's ideas seem, initially, sensible. Bolstered by our society's technological bias, many students enter a university under the influence of Western culture boasting ever-evolving and improving innovations to meet our ever-escalating needs. Students expect biological evolution to be driven by the same engines of progress. Nothing, of course, could be further from the truth. Biological evolution is not driven by needs. Therefore, a modern student arrives on the doorsteps of such a course already harboring mistaken expectations that must be addressed head on before any of this can be understood. Understanding what Darwin had to say is much more than just examining the formal evidence for evolution. In a sense, each student must make an intellectual journey, to step outside the pervasive grip of the industrial and technological culture of our day. Organisms, Survival, Fitness
Third, I have also chosen to depart from the standard treatment of evolution in other textbooks on evolution, wherein the arguments are reductionist, molecular, and overwhelmingly genetic in flavor. Certainly genetics plays a large and indispensable role in evolutionary thought, and genetics is covered here within these pages as well. But the much-deserved pride geneticists take in the success of their field has led to a hubris, tempting some to believe that evolution is little more than a genetic shell game. As one such scientist rhapsodized, "it is only in genetics that there can be said to be a 'theoretical biology' ...." Such claims, taken alone, are much too narrow to provide a full understanding of Darwinian evolution. This is especially true now that the successes of evolutionary morphologists and ecologists have taken the science from laboratories into the wild, and documented the workings of natural selection in nature. Organisms in populations are the center of the evolutionary action, so it is here, on organisms, that I center this book.A Book to be Read
I have tried hard to write an inviting book that will be read—by students. The WEB offers wonderful resources accessed through powerful search engines. This is a comfortable medium for students of today who have grown up mostly in a virtual world of information. But printed books remain important and even unique vehicles of information and ideas--they are convenient; they are reviewed and edited; they are organized sources of information; they can be thought provoking; they are coherent with a common voice. With a textbook in hand, the instructor of a course knows the information and slant to the subject presented to students. The instructor can then build the course they want, expanding or amending or even constructively disagreeing. But to serve this central and supportive role, the textbook must be read.
Many current textbooks are excellent encyclopedias of information. But too many are overbearing and stately--often mannered in presentation. They go unread by students. And that is a shame. I therefore experiment here with a writing style that I hope will engage students and encourage them to read, to pause and consider, then to read further.Organization and Rationale
I do not pit evolution against fundamentalism, red in tooth and claw. Instead, the book is focused on the science of Darwinian evolution. I open by placing Darwin's ideas in historical context, but for the purpose of identifying particular scientific obstacles he faced—time and heredity. The remainder of the book brings evolution into a modern context, explores the biological implications, and concludes with a timely consideration of evolution to human society today. Topics and chapters can be reordered to suit particular courses. Reasonably, everyone using this book will follow his/her strategy, and the book supports this. Let me share my thinking on one approach.
Chapters and Topics
Chapter 1 (Evolution of Evolution)
Chapter 2 (Time)
Chapter 3 (Heredity)
Darwin's great achievement was not in proposing that organisms evolved. In fact, evolution was discussed by ancient Greek philosophers before the time of Christ, and thus was old news in Darwin's day. Most of the evidence was available to nineteenth century contemporaries, but Darwin was first to see around the distractions, misinformation, and scientific confusion and put it all together. And his insight was profound, even disturbing, still the subject of serious debate, and still being analyzed for its implications to ourselves, to our politics, and to our basic ethical systems. To understand this larger significance of evolutionary principles, most students must make much the same intellectual journey as did Darwin. What did Darwin say? And what were the scientific objections of his contemporaries? With all the contentious religious objections receiving attention, then and now, we tend to forget that Darwin faced serious scientific challenges to his views. As a unit, these first three chapters set up the issues, and then show how each is resolved today.
Chapter 4 (Emergence of Life)
Chapter 5 (Diversity of Life)
What can be done about the biological background of students? At best, it is uneven. In some states, all students now have at least a brush with biology on their way through high school. And we should credit television with bringing nature programs to a general public. These chapters cannot, of course, substitute for a proper background course in biology. But I have tried to pack into these two chapters enough to refresh the memories of students with prior courses in biology. For those without such backgrounds, I have tried to be sure that all biological principles they meet elsewhere in the book are at least mentioned here, in these chapters, in a cohesive context. Chapter 4 notes the major, early transitions of life, and in so doing students meet the prokaryotes; here the step to organic evolution occurs, heterotroph to autotroph, the appearance of a eukaryotic cell, and the basic coding structure of life itself is described—DNA, RNA. Chapter 5 places before us the further cast of characters in the evolutionary story, the eukaryotes—protists, plants, fungi, and animals.
Chapter 6 (Evidence of Evolution)
Now we are ready to critically examine the formal, scientific evidence favoring a natural explanation for evolutionary change, piece by piece. This chapter especially offers the chance to engage students in critical thinking. Formally, the chapter provides the student a chance to join in hypothesis testing, which is somewhat of the form If…, then…, thus. A hypothesis is stated, its implications or predictions are identified, and then these are tested. If the predictions are accurate, then the hypothesis is supported and thus a tentative conclusion is drawn.
Chapter 7 (Selection)
Chapter 8 (Variation: Spice of Life)
Chapter 9 (Speciation)
Chapter 10 (Co-Evolution)
Chapter 11 (Life History Strategies)
Chapter 12 (Life in Groups)
If the curiosity of students is tweaked, then they will want to know more about how the process of evolution works. Chapter 7 explores the workings of natural selection. Evolution runs on variation. The sources of this variation—genetic shuffling and mutations—receive attention in chapter 8. Chapter 9 examines how new species actually arise and chapter 10 reflects on how species interact in co-evolutionary relationships. We are reminded in chapter 11 that life histories evolve, not just adults. Levels of selection and life in groups enters a controversial area in chapter 12—individual versus group benefits; here we also meet issues of microevolution and macroevolution as they might help understand how evolution sometimes advances in macro steps, to produce rapid changes.
Chapter 13 (Extinctions)
In chapter 13 we explore the other side of evolution, extinctions wherein old species become extinct in a boom (mass) or a whimper (background); here the story of "hot-" or "cold-blooded" dinosaurs is also discussed.
Chapter 14 (Human Evolution: The Early Years)
Chapter 15 (Human Evolution: Building Modern Humans)
By this point in the book, we have examined the workings of natural selection and the way in which complex associations arise. We are ready for our own evolution, discussed in these two chapters.
Chapter 16 (Evolutionary Biology: Today and Beyond)
Evolution happens. It happens today. It is an ongoing process that cannot be ignored, especially as humans take over much of the responsibilities for building a better genetic and social future. This concluding chapter considers evolution's implications in modern society, including its implications for molecular genetics with its possibilities and pitfalls, and how peoples and plagues continue the evolutionary race.Acknowledgements
From Charles Darwin to the present, evolutionary biology has grown into a major scientific discipline that unites all of the life sciences and holds a view of life that touches us all. Bringing this to a wider audience is a passion I shared with a team of publishing professionals and special reviewers, without whom this first edition would not have been feasible. I am indebted to the core publishing group who believed in this project and contributed their talent and time I am especially grateful to several in particular: As always, it was a delight to work with Sue Dillon, who brought her special copyediting talents and sympathetic support to early versions of a scruffy manuscript. At McGraw-Hill, Marge Kemp (publisher), from the beginning, saw merit and possibilities in this unique book, and helped nurture it through all stages of production. It is hard to overstate the remarkable good judgment and dedicated effort Kathy Loewenberg (developmental editor) brought to this project; she could be "red in tooth and claw" or encouraging, depending on what was needed to keep our team on track. Additionally, my thanks go to many others who helped at various stages, including Joyce Berendes (project manager), Francine Banwarth (proofreader), Wendy Nelson (copyeditor), David Hash (design manager), John Rokusek (cover design), Sandy Ludovissy (production supervisor), Judi David (media producer), and Lori Hancock/Pam Carley (photo research). I thank as well the McGraw-Hill field staff who link the summary effort of all who helped in this book to faculty and students who use it. In turn, these field reps return your comments of what you do and do not like, and thereby aid in the improvement of this textbook, making it a shared work in progress. My thanks also to Donna Nemmers for her dependable good humor.
–Ken Kardong |
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McGraw-Hill Higher Education