Introduction to Evolutionary Anthropology (PDF)

vanqc&i INTRODUCTION TO EVOLUTIONARY ANTHROPOLOGY E volution is topical, evolution is engrossing, and evolution holds the answers to some of the world's most fascinating anthropological questions....

vanqc&i INTRODUCTION TO EVOLUTIONARY ANTHROPOLOGY E volution is topical, evolution is engrossing, and evolution holds the answers to some of the world's most fascinating anthropological questions. Shawn M. Lehman Introduction to Evolutionary Anthropol ogy Shawn M. Lehman University of Toronto Pearson Canada Toronto Library and Archives Canada Cataloguing in Publication Lehman, Shawn M. Introduction to Evolutionary Anthropology / Shawn M. Lehman. Includes index. ISBN 978-0-13-207822-1 1. Social evolution — Textbooks. 2. Human evolution — Textbooks. 3. Primates — Evolution — Textbooks. 4. Anthropology — Textbooks. I. Title. GN25.L43 2010 301 C2008-907613-3 Copyright © 2010 Pearson Education Canada, a division of Pearson Canada Inc., Toronto, Ontario. Pearson Prentice Hall. All rights reserved. This publication is protected by copyright and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permission, write to the Permissions Department. ISBN-13: 978-0-13-207822-1 ISBN-10: 0-13-207822-8 Vice President, Editorial Director: Gary Bennett Editor-in-Chief: Ky Pruesse Senior Acquisitions Editor: Laura Forbes Signing Representative: Sally Aspinall Marketing Manager: Arthur Gee Developmental Editor: Rema Celio Production Editor: Lila Campbell Copy Editor: Lisa Berland Proofreaders: Colleen Ste. Marie, Madeline Koch Production Manager: Peggy Brown Composition: Macmillan Publishing Solutions Art Director: Julia Hall Cover Design: Anthony Leung Cover Image: Firefly Productions/CORBIS Cartoons: Angus Bungay 12 34 5 13 12 11 10 09 Printed and bound in the United States of America. PEARSON For Christine and Joshua, always and —forever. S.M.L  Digitized by the Internet Archive in 2014 http://archive.org/details/introductiontoevOOshaw  ABOUT THE AUTHOR Shawn M. Lehman is an associate professor in the Department of Anthropology at the University of Toronto. Among his field experiences are expeditions to jungles in Venezuela, Guyana, Suriname, and Madagascar. He earned his Ph.D. in anthropology at Washington University in St. Louis. His doctoral research focused on the biogeography of nine primate species in Guyana, South America. Following his doctoral work, he undertook research on the conservation biogeography of lemurs in Madagascar. Dr. Lehman and his students are currently exploring innovative approaches to determine how landscape changes in forest composition influence lemur ecology in Madagascar. He is also a dedicated and enthusiastic lecturer, having been nominated three times for TVO's Best Lecturer Competition. Preface xi Chapter 1 Introduction to Evolutionary Anthropology 1 Chapter 2 Microevolution and Evolutionary Anthropology 21 Chapter 3 Macroevolution and Evolutionary Anthropology 42 Chapter 4 Living Primates 60 Jc i rinidic wrigin Q1 n a nfpr 1 I I v 1PitqI" Tnp Hal Hnminur; 1 1 Will I I I I in 117 Chapter 7 Human Origins: Rise of the Genus Homo 137 Chapter 8 Human Variation 154 168 Chapter 9 Applied Anthropology Glossary 187 195 Index  CONTENTS Preface xi An Introduction to Cladistics 49 53 Macroevolution: Species Diversity CHAPTER 1 on a Grand Scale Macroevolutionary Patterns and Processes 53 Introduction to Evolutionary Anthropology 1 54 Phyletic Gradualism What Do Evolutionary Anthropologists Study? 4 Punctuated Equilibrium 55 Primatology 4 Which Is It: Phylogenetic Gradualism Paleoanthropology 4 or Punctuated Equilibrium? 56 Human Variation 4 The Modern Synthesis: Putting Medical Anthropology 5 All This Stuff Together 57 Forensic Anthropology 5 How Do Evolutionary Anthropologists CHAPTER 4 Conduct Their Research? 5 Living Primates 60 What's a Theory? 6 Primate Taxonomy and Characteristics 61 What's a Hypothesis? 6 Strepsirhini 62 The Scientific Method 6 Haplorhini 67 Development of Evolutionary Concepts 7 76 Historical Contributors 7 Body Size Effects of Body Size on Primate tife 77 Charles Darwin and the Theory of Natural Selection 9 Ecology and Behaviour 78 Misconceptions about Darwin's Ideas 13 Primate Habitats 78 Introduction to Mendelian Genetics 15 Primates in Tropical Ecosystems 79 What Actually Happened in Mendel's Experiments? 17 Sociality 80 Ranging Patterns 81 CHAPTER 2 Social Grooming 81 Microevolution and Evolutionary Dominance Hierarchies 81 Anthropology 21 Classifying Primate Social Organizations 84 Genetic Basis of Inheritance Why Do Primates Live in Groups? 84 and Biological Evolution 22 Conservation 85 Chromosomes and Genetic Materials 22 Effects of Agriculture on Primates 85 Mutation: The Ultimate Source of Genetic Variation 28 Effects of Forest Fragmentation on Primates 87 Population Genetics 31 Effects of Hunting on Primates 87 Genetic Drift 31 Conservation Status of Primates 87 Gene Flow 33 CHAPTER 5 Natural Selection and Adaptation 34 Natural Selection Revisited 34 Primate Origin 91 What's an Adaptation? 37 Introduction to Fossil Primates 92 Behavioural Adaptations and Biological Evolution 38 Basics of Primate Dentition 92 Misconceptions about Natural Selection Basics of the Primate Skeleton 94 96 and Adaptation 38 98 How Do We "Know" What Fossil Primates Were Like? CHAPTER 3 Theories on Primate Origins Ecosystem and Temporal Aspects Macroevolution and Evolutionary of Primate Origins 99 Anthropology 42 101 Species and Speciation 44 Paleocene "Primates" 101 Paleocene Mammals: Any Primates Here? What's a Species? 44 Phylogenetic Relationships among What's Speciation? 48 102 Paleocene "Primates" IX  X Contents Eocene Primates: Are We There Yet? 1 02 Homo heidelbergensis and Homo antecessor 143 Homo neanderthalensis 1 44 Finally, the First "Modern" Primates! 102 Phylogenetic Relationships among Homo floresiensis 1 44 Eocene Primates 103 Homo sapiens 1 45 Oligocene Primates: Hey, Is It the Monkeys? 1 05 Early Hominin Tools: From Pebbles Morphological Features of Oligocene Primates 105 to Works of Art 1 46 Phylogenetic Relationships among Low Palaeolithic Period 146 Oligocene Primates 107 Middle Palaeolithic Period 148 Miocene Primates: Planet of the Apes 1 08 Upper Palaeolithic Period 148 Morphological Features of Miocene Primates 1 08 Hominin Phylogenetic Relationships 150 Phylogenetic Relationships among Miocene Primates 111 CHAPTER 8 Pliocene Primates: Return of the Monkeys! 112 Morphological Features of Pliocene Primates 1 12 Human Variation 154 Phylogenetic Relationships among Pliocene Monkeys 113 Human Origins: Replacement or Multiregional Hypotheses? 155 Replacement Hypothesis 155 CHAPTER 6 Multiregional Hypothesis 156 The First Hominins 117 The Evidence! 157 Natural Selection and Human Adaptation 158 Introduction to Fossil Hominins: From Body Size and Shape 159 Small Brains and Big Teeth to Big Brains and Small Teeth 118 Skin Colour Adaptations 160 Are There Human Races? 1 62 What's a Hominin? 118 Morphological Trends in Hominin Evolution 1 19 Evolutionary Anthropologists and Human Races 162 Finding and Estimating the Age of What's the Deal with "Racial" Abilities? 1 64 Fossil Hominins 123 Transitional Forms: Advanced Apes CHAPTER 9 or Primitive Hominins? 126 Sahelanthropus tchadensis 1 26 Applied Anthropology 168 Orrorin tugenensis 127 Perinatologists and Applied Anthropology 1 70 Ardipithecus ramidus and Ardipithecus kadabba 1 28 Applied Anthropology and Habitat Disturbance 1 71 Kenyanthropus platyops 1 28 Applied Anthropology and Primate Hunting 1 71 Applied Anthropology and Primate Ecotourism 1 72 Australopithecines: The First "Real" Hominins 129 Australopithecus anamensis 1 30 Medical Anthropologists and Australopithecus afarensis 1 30 Applied Anthropology 1 74 Australopithecus bahrelghazali 1 30 Applied Anthropology, Biological Evolution, and Disease 1 74 Australopithecus africanus 131 Australopithecus garhi 1 32 Applied Anthropology, Nutrition, and Health 1 78 Australopithecus aethiopicus 1 32 Forensic Anthropology: Cool TV Shows, Australopithecus boisei 1 33 Cooler Science 181 Australopithecus robustus 1 33 Determining Age from Skeletal Remains 1 81 Cradle and Robust Australopthecines 1 34 Determining Sex from Skeletal Remains 183 Determining Trauma from Skeletal Remains 183 CHAPTER 7 Glossary 187 Human Origins: Rise of Index 195 the Genus Homo 137 Homo: Bigger Brains, Smaller Teeth 1 38 Homo habilis and Homo rudolfensis 140 Homo erectus and Homo ergaster 142  PREFACE Biological evolution is integral to research in fields ranging from anthropology to zoo- logy, making it one of the most fascinating subjects in science. Biological evolution is topical, biological evolution is engrossing, and biological evolution holds the answers to some of the world's most fascinating anthropological questions. For example, pale- oanthropologists seek answers to the intriguing questions of who we are and where we came from. Anthropologists studying primates work to determine what role these fasci- nating creatures play in tropical ecosystems, and they help us understand the human condition. Medical anthropologists delve into the evolutionary essence of why, after 100 000 years or so of natural selection, humans still suffer from myriad health issues. Forensic anthropologists represent an applied field more popular now than ever before, due in part to associated television shows and bestselling books. Despite the fact that just about everyone has an inherent interest in biological evolution, there exists a rather perplexing issue: introductory textbooks in biological anthropology often come across as, in the words of many of my students, dull and boring. Introduction to Evolutionary Anthropology represents a new, exciting perspective on the field of evolutionary anthropology for first-year students at universities and colleges. Distinctive Aspects of Introduction to Evolutionary Anthropology Focus on Biological Evolution This book focuses on biological evolution with an anthropological perspective. Each chapter deals exclusively with evolutionary concepts, particularly those that are rarely mentioned in other introductory textbooks. For example, Introduction to Evolutionary Anthropology consistently employs phylogenetics and cladistic trees as tools for under- standing patterns and processes in human evolution. Readers are given the tools to interpret phylogenetic trees rather than the overly complex methods for constructing them. Originality, Personality, and Energy I provide unique examples of evolutionary research and my own personal experiences to make seemingly complex evolutionary concepts accessible to students. Each chapter commences with a first-person narrative in which I highlight a personal experience with the topic that follows. Some examples and stories are humorous, others are adventurous, and a few are serious. These stories connect students to the pervasive influence of biological evolution in their world, putting a personal touch on what can be a very impersonal process in large, introductory classes. The energetic writing style and topical examples are designed to engage students, without sacrificing the quality of the science. Chapter Brevity Chapters are concise, enabling students to work quickly through their assigned readings. Students are then ready to assimilate lesson plans during lectures or podcasts. Consequently, this book is designed to fit within a single-semester course. xi Unique Application of Illustrations, Cartoons, and Humour In addition to many original line drawings and colour photographs, Introduction to Evolutionary Anthropology uses a novel series of editorial cartoons to help students see the humorous side of common misconceptions about evolutionary anthropology. I see humour as a powerful pedagogical tool, when applied appropriately. Consequently, the book contains, here and there, humorous reflections and anecdotes to help students learn about the field that fascinates us as professional anthropologists. Some URLs in the end-of-chapter Internet Resources provide amusing videos of ideas and concepts within the associated chapter. Highlights of the Chapters Chapter 1: Introduction to Evolutionary Anthropology This chapter introduces students to the modern, holistic application of anthropological theory in the following five disciplines: sociocultural, linguistics and semiotics, archae- ology, medical, and biological anthropology. With this background, the biological subfield of evolutionary anthropology is introduced, as is the scientific method. I then provide a short review of the historical development of evolutionary concepts, includ- ing an appraisal of Charles Darwin's life and of how he came to formulate his theory of natural selection. The chapter concludes with a short review of Gregor Mendel's work on trait inheritance and a discussion of why creationism and "intelligent design" are scientifically bankrupt. Chapter 2: Microevolution and Evolutionary Anthropology In this chapter, I introduce the main processes and patterns in modern evolutionary theory as they pertain to microevolution. What's microevolution? Put simply, it refers to small changes in evolution, such as a change in a population's gene pool over a suc- cession ofgenerations. I begin the review by looking at the genetic basis of inheritance. My use of simplified examples of transcription and translation enables students to bet- ter understand what exactly was going on at the genetic level in Mendel's experiments. From there, I delve into genetic changes at the population level. Finally, I review the four mechanisms of biological evolution: mutation, genetic drift, gene flow, and natural selection. I conclude the chapter by clearing up common misconceptions regarding natural selection and mutation. Chapter 3: Macroevolution and Evolutionary Anthropology This chapter covers macroevolution, which encompasses large-scale changes at or above the species level extending over geologic eras and resulting in the formation of/hew taxonomic groups. I explore fundamental issues ofyspecies concepts! and(how species evolve^I then expand the review of(modern evolutionary theoryjfrom the species level to that of a community of different species in space and time. Finally, I describe the^modern synthesis, which establishes the primacy of biological evolution) for understanding the history of life on our planet. Chapter 4: Living Primates The purpose of this chapter is to introduce students to the exciting science of primate studies in evolutionary anthropology. Students use an up-to-date taxonomy for pri- mates to provide order for a general review of living primates. I then provide specifics on how to differentiate the various taxonomic groups within the Order; There is an extensive and lively discussion of fundamental aspects of the evolutionary anthropology of primates, including body size, ecology and behaviour, and conservation. Chapter 5: Primate Origin This chapter offers a review of the evolutionary anthropology of non-human primates in the fossil record. The major goal of the chapter is to give students an understanding of how and why primates evolved from the time of the dinosaurs up until the emergence of the first hominins. Each section starts with a review of the major global patterns of geography and climate. This information is needed to understand how environmental factors influenced primate macroevolution. I undertake a brief review of the major mor- phological characteristics and ecological interpretations of the primates associated with that epoch. Finally, I piece together the phylogenetic relationships of early primates. Chapter 6: The First Hominins In this chapter, students meet species that may be our earliest common ancestors with living apes. Specifically, students learn about major trends in the evolutionary anthro- pology ofhuman origins during the Pliocene and Pleistocene epochs. Major fossil species receive a brief review of their morphological characteristics and ecology. This chapter sets the stage for understanding the broad evolutionary patterns that resulted in human origins. Chapter 7: Human Origins: Rise of the Genus Homo This chapter introduces students to paleoanthropology as an exciting and rewarding academic pursuit. I discuss the evolutionary anthropology of human origins starting with the emergence of the first species in our genus {Homo). Students also learn about the origins of and changes in tool use over the course of millions of years. Finally, I piece together the phylogenetic relationships of hominins. Chapter 8: Human Variation In this chapter, students learn that evolutionary anthropologists are at the forefront of science in documenting phenotypic and genetic diversity of modern humans. This research seeks to provide us with an improved understanding of where we came from and why we look the way we do. Thus, the purpose of this chapter is to discuss the evolutionary anthropology of human variation. I start with looking at the main hypotheses on human origins, followed by a review of human adaptations, ranging from body size to disease. Finally, I provide a detailed, evolutionary perspective on the fallacies of human race concepts and so-called racial abilities. Chapter 9: Applied Anthropology The book concludes with a discussion of the application of anthropological knowledge to solve practical problems. In the course of conducting their research, many evolutionary anthropologists have an opportunity to assist in resolving environmental issues with their study animals, or social and health problems with local human populations. I also discuss specifics of the practical application of anthropological knowledge in primatology, med- ical anthropology, and forensic anthropology. I conclude the chapter with a review of forensic anthropology — the application of skeletal biology to issues within a legal setting. Supplements The following instructor supplements are available for downloading from a password-protected section of Pearson Education Canada's online catalogue (www.pearsoned.ca/highered). Navigate to your book's catalogue page to view a list of those supplements that are available. See your local sales representative for details and access. Instructor's Resource Manual: This manual includes additional resources and exercises that can be assigned to students to further their study and interest in anthropology. PowerPoint Presentation Slides: The PowerPoint Presentation Slides offer key concepts and key figures from the text and can be used during lecture to highlight key points in the text. Test Item File: This test bank created in Microsoft Word format includes a variety of questions, such as multiple choice, true/false, short answer, and essay-type questions that can be used for testing students on their understanding of core concepts discussed in the text. This test bank is also available in MyTest format (see below). MyTest: MyTest is a powerful assessment generation program that helps instructors easily create and print quizzes, tests, exams, as well as homework or practice handouts. Questions and tests can all be authored online, allowing instructors ultimate flexibility and the ability to efficiently manage assessments at any time, from anywhere. CourseSmart eTextbook CourseSmart is a new way for instructors and students to access textbooks online anytime from anywhere. With thousands of titles across hundreds of courses, Course- Smart helps instructors choose the best textbook for their class and give their students a new option for buying the assigned textbook as a lower cost eTextbook. For more information, visit www.coursesmart.com. Acknowledgments This book represents a personal journey of sorts, ranging from my days as a young student-athlete at the University of Calgary to my current role as mentor to a new generation of anthropologists at the University of Toronto. Like all journeys, there are important people to acknowledge along the way. My family accepted my unique career choice, despite the rather dreary job outlook for biological anthropologists at that time. Thanks to my parents, I knew that no matter how far I travelled or how much trouble I encountered, I always had a wonderful place called home to return to. My patient undergraduate advisors, James Patterson and Linda Taylor, taught me that biological evolution is an integral part of the anthropological perspective. Because of their sup- port and guidance, I was fortunate to attend graduate school at Washington University in St. Louis. During this time, I was privileged to learn from some of the top minds in evolutionary anthropology, particularly my Ph.D. advisor, Robert W. Sussman as well as Jim Cheverud, Glenn Conroy, Jane Phillips-Conroy, and Richard Smith. I am indebted to Robert Sussman and Linda Taylor for hammering, quite literally, my nas- cent skills in scientific and grant writing into something resembling that of a profes- sional academic. I also thank my fellow graduate students at WashU, including Pamela Ashmore, Thad Bartlett, David Bergeson, Shimelis Beyene-Gebru, Ian Colquhoun, Ben Freed, Lisa Gould, Donna Hart, Kevin Kykendall, Laura Marsh, and Myron Shekelle. Following graduate school, my understanding of evolutionary anthropology was greatly enhanced by faculty and students at SUNY-Stony Brook, including Summer Arrigo-Nelson, Diane Doran, Fred Grine, Mitchel Irwin, Charles Janson, William Jungers, Curtis Marean, Jonah Ratsimbazafy, Karen Samonds, Nancy Stevens, John Shea, and Chia Tan. I am particularly grateful to John Fleagle and Patricia Wright at SUNY-Stony Brook, whose collegiality and support continue to sustain my intellectual and career development. I would like to thank a number of my colleagues and students in the Department of Anthropology at the University of Toronto who have been instrumental in my never-ending quest to learn and teach about our fascinating biological world, including Katherine Bannar-Martin, David Begun, Laura Bolt, Andrea Falkner, Tracy Kivell, Keriann McGoogan, Mariam Nargolwalla, Michael Schillaci, Dan Sellen, Courtney Sendall, and Angel Vats. I acknowledge the incomparable administrative and business staff in the department office, particularly Josie Alaimo, Annette Chan, and Natalia Krencil. I would like to thank the acquisitions and development people at Pearson Educa- tion Canada, particularly Laura Forbes and Sally Aspinall, who took somewhat of a risk in letting me put my rather unique ideas into a textbook. From our first meeting, they embraced my desire to produce a textbook similar to my teaching pedagogy, resulting in a text different from any currently available to teachers and students. I greatly appreciate the editorial work done by Lisa Berland, Lila Campbell, Rema Celio, Charlotte Morrison-Reed, and Colleen Ste. Marie. They are a wonderful team to work with. I am indebted to colleagues, current and former students, and photographers who provided images and data for use in the text. A very special thanks goes to Angus Bungay for using his creativity, enthusiasm, and artistic talents to give such vibrant life to Cucu, Bento, and Geo; long may they live! I thank the reviewers whose suggested changes greatly improved drafts of the book during production: Steig Johnson, University of Calgary; Michael Schillaci, University of Toronto; Janet Padiak, McMaster University; Alexis Dolphin, University of Western Ontario; Ildiko Horvath, McGill University; Pamela R. Willoughby, University of Alberta. I am partic- ularly grateful to colleagues who reviewed some of the chapters, including David Begun, Joyce Parga, James Rising, Michael Schillaci, David Strait, and Patricia Wright. Any remaining errors or omissions are mine, and mine alone. Finally, I thank my little family for their love and support, including the gentle presence of Persia, our cat. My deepest love and respect go to my beautiful wife, Christine, and my exuberant son, Joshua; they are my world. Their support sustained me during the dark winter months, when completing this book seemed almost impossible. I also thank Christine and Joshua for their patience and understanding in accepting that my work often takes me away physically, but never spiritually, from their loving presence. Introduction to Evolutionary Anthropology GOALS By the end of this chapter you should understand: 1. Research topics explored by evolutionary anthropologists. 2. Basics of the scientific method. 3. Historical development of evolutionary concepts. 4. Charles Darwin and the theory of natural selection. 5. Gregor Mendel's studies of trait inheritance. CHAPTER OUTLINE What Do Evolutionary Anthropologists Study? How Do Evolutionary Anthropologists Conduct Their Research? Development of Evolutionary Concepts  2 CHAPTER i Introduction to Evolutionary Anthropology Introduction I remember my first course in anthropology. Because my initial request for a course on biological evolution was denied due to enrolment limits, a friend suggested I take a popular course focusing on what he called "monkey stuff." Sounded interesting, I thought, so I enrolled in Introduction to Biological Anthropology. Being a newcomer to campus, I got lost and was late for the first class. As I hurried toward the classroom, I heard strange animal-like noises echoing off the lockers in the hallway. The noises got louder as I approached my designated room. I stepped into the classroom to discover the professor hooting like a wild monkey! As I negotiated through the seats already occupied by my fellow students, the professor told us about the course. In the weeks ahead, we would learn about the mechanisms of biological evolution, the ecology and behaviour of our closest biological relatives, and the anatomical trends in our biological evolution. In our studies, we sought to answer the question, what is it to be human? I knew by the end of the course that I wanted to be an anthropologist! What's the first thing that comes to your mind when you hear the word anthropology? Perhaps you picture researchers studying primitive human cultures deep in the jungle, archaeolo- gists struggling to locate treasures in the ruins of ancient cities, or scientists digging for fossils under Anthropology The the blazing sun in Africa. Certainly, some aspects of all these activities relate to anthropology. global and holistic Anthropology is a holistic science comprising the following five disciplines: socio-cultural anthro- study of human culture and biology. pology, linguistic and semiotic anthropology, archaeology, medical anthropology, and biological anthropology. Socio-cultural anthropology is the comparative study of human cultures and soci- Holistic Considering eties. Linguistic and semiotic anthropology focuses on how language and other systems of human all aspects of the research subject. communication contribute to the reproduction, transmission, and transformation of culture. Archaeology is the scientific study of the material evidence of human activities in the past. Medical anthropology focuses on human health and its relationship with culture, behaviour, and biology. Non-human primate Biological anthropology is the study of human and non-human primates in their biological Any primate that is and demographic dimensions. Evolutionary anthropology, a specialized subdiscipline within not a human. biological anthropology, is the application of modern evolutionary theory to studies of the Morphology The morphology, ecology, and behaviour of human and non-human primates. This book employs study of the form and structure of organisms. an evolutionary perspective on humans and non-human primates. Why? Because as a famous evolutionary biologist stated, "Nothing in biology makes sense except in the light of evolution" Ecology The study (Dobzhansky, 1 973). of interrelationships of Biological evolution and other associated processes influence every aspect of our lives (Groen organisms and their environment. et al., 1 990). Do you like good food and drink? Our ability to taste, smell, and in some cases detoxify food results from evolutionary processes. Do you like looking at artwork or participating in sports? Our ability to see in colour and judge distance is the result of millions of years of natural selection. Do you like scary movies? If so, then perhaps you have noticed that watching a scary movie often makes the hairs stand up on your arms and the back of your neck. This uncontrolled response is similar to what happens to frightened cats: they fluff up. A tiny muscle, the arrector pilorum, can raise each hair on the human body. The body's response to being scared is to revert to an ancient mammalian trick of looking bigger and more imposing to some perceived external threat! As you will learn in the upcoming chapters, biological evolution has influenced and contin- ues to influence humans, as it has all other life forms on Earth. Evolutionary concepts are hidden in some of the most popular movies, television shows, and advertisements. For example, the computer-animated movie Finding Nemo is the story of a clownfish (Amphiprion ocellaris), named Marlin, who loses his wife and all but one of their offspring to a predator. The remainder of the movie describes Marlin's heroic efforts to find and save his son Nemo from captivity. However, clownfish biology is different from that portrayed in the movie: The death of the resident breeding female, such as Nemo's mom, results in one of the local males, like Marlin, changing sex to become the new breeding female. Yes, you read that correctly: Marlin should have become Marlina!  Introduction to Evolutionary Anthropology 3 Speaking of cartoons, you will see a number of editorial cartoons used in this text to help you understand the humorous side of common misconceptions about biological evolution (starting with Figure 1.1). This chapter will introduce you to the exciting science of evolutionary anthropology. ^Please take a. moment to] El*VANGERBV SP£ClSS meet your, nei CONFERENCE Figure 1.1 Introducing three characters — Cucu, Bento, and Geo — who at various points in the book provide a comical view of common misconceptions people have about evolutionary concepts.  4 chapter i Introduction to Evolutionary Anthropology What Do Evolutionary Anthropologists Study? Evolutionary anthropologists and biologists seek answers to intriguing questions of where we come from, who we are, and why we are here (Futuyma, 1998). Evolution- ary anthropologists specialize in primatology, paleoanthropology, human variation, medical anthropology, and forensic anthropology. Below is a brief introduction to these five research disciplines. Primatology Extant Living Primatology is the scientific study of our closest extant biological relatives: non- representatives of human primate species. For now, we can define species as a single, distinct class of a species exist. living creature with features that distinguish it from other living creatures. You can find a more detailed explanation of species concepts in Chapter 3. Primatologists Primate Any extant conduct their research on a variety of primate species and research topics, ranging or extinct member of the order of mammals from descriptions of primate anatomy through field studies of wild animals to inves- that includes lemurs, tigations ofprimate psychology. Primatologists are at the forefront of research efforts tarsiers, monkeys, to conserve primates in vanishing tropical ecosystems. For example, Dr. Colin apes, and humans. Chapman and his research team at McGill University have spent decades studying how primates respond to deforestation in Africa (Chapman et al., 2000, 2005). Their groundbreaking work indicates that even 15 to 25 years after logging, the abundance of some primate species have still not returned to levels recorded before logging occurred. They have linked this slow recovery to a fascinating pattern of temporal and spatial variations in parasites and the quality and abundance of food resources. Paleoanthropology Paleoanthropology is the multidisciplinary study of the biological evolution of humans and non-human primates. Although paleoanthropologists are perhaps Fossils Organic best known for excavating fossils, many researchers also investigate the advent of remains that have and changes in human cultural activities, including tool use, subsistence patterns, been transformed by geological processes and disease. We know that the primate fossil record stretches back as far as 50 to into a mineralized 60 millions years (Fleagle, 1999). Ancient primates evolved and went extinct in form. response to a variety of geological and biological processes. Paleoanthropologists also Extinct No living investigate the evolutionary history of behaviour in human and non-human primates. representative of a For example, Dr. Mark Collard of Simon Fraser University combines biological evolu- species exists. tion and archaeology to understand patterns of primate and human evolution (Collard and Wood, 2000; Lycett et al., 2007). Dr. Collard has suggested that the behavioural patterns of some primates result from social learning, and that these creatures share with humans the unique distinction of having culture. Human Variation Anthropologists study human variation to determine spatial and temporal variations in human features (Jobling et al., 2004). Observe your fellow humans the next time you are on campus or at another major urban centre, such as an international airport. You're likely to see that we come in an impressive array of sizes, shapes, and colours. We also have considerable skeletal and dental variations, which are, of course, much harder to see. Despite this variation, all humans are members of one species, which evolutionary anthropologists refer to as Homo sapiens. For example, Dr. Esteban Parra at the University of Toronto-Mississauga uses genetic markers to answer questions related to the biological evolution of skin pigmentation in human populations (Parra  How Do Evolutionary Anthropologists Conduct Their Research? 5 et al., 2001; Shriver et al., 2003). This research indicates that human skin pigmentation has been subject to strong selection pressures due to environmental factors rather than population history. Medical Anthropology Medical anthropology, the study of how social, environmental, and biological factors influence health and illness of individuals at the community, regional, national, and global levels, is a recent addition to evolutionary anthropology. Many medical anthropologists investigate spatial and temporal variations in human survival, disease, and health disparity. Dr. Robert Hoppa, of the University of Manitoba, investigates the interactions between environment, health, and behaviour in ancient human populations (Green et al., 2003; Hoppa, 2000). Dr. Hoppa and his research team are conducting groundbreaking studies of the skeletons of the indigenous peoples of Canada to recon- struct their cultural history at both the individual and population levels. Forensic Anthropology Forensic stuff fascinates many people! If you watch television, then you are likely aware of popular programs, like Bones and the CSI series, that deal with forensic scientists and their work on homicide investigations. There are equally popular books dealing with forensic science, such as Patricia CornwelPs series on the fictional charac- ter Dr. Kay Scarpetta. While forensic science encompasses a variety of biological fields of research, such as genetics and toxicology, forensic anthropology focuses only on the skeletal remains of humans. By analyzing these remains, forensic anthropologists seek to determine the age, sex, stature, ancestry, and any trauma or disease of the deceased. For example, Dr. Mark F. Skinner from Simon Fraser University has consulted on hun- dreds of forensic cases in Canada (Bell et al., 1996; Skinner, 1987). Dr. Skinner has also investigated allegations of mass graves in Afghanistan, Bosnia, Serbia, and East Timor. How Do Evolutionary Anthropologists Conduct Their Research? Evolutionary anthropologists conduct three types of research: descriptive, causal, and applied (Bryman, 2001). Descriptive research involves collecting data about the study subjects or objects. If, for example, I were to walk through a forest recently damaged by logging and notice that some primate species were missing, I would be conducting descriptive research. However, although my observations are of conservation interest, they do not provide a means to determine what caused the primates to disappear. They could be gone because of hunting pressures, loss of critical food resources, sensitivity to habitat disturbance, or any number of other factors. Therefore, you can see that descriptive research does not demonstrate causal relationships. Causal research involves looking for one thing that causes another thing to happen or change. Returning to my previous example, I could look for a cause-and-effect relationship between ecological factors, such as the distribution and density of critical food resources and the loss of primate species in the logged forest. Medical and forensic anthropologists tend to focus on applied research. In applied research, a scientist determines the means by which a specific, recognized need can be met (Miller and Salkind, 2002). Applied research can also be used in the previous example of deforestation effects on local primates. If one of my variables, such as the distribution of food resources, was a strong predictor of primate diversity, then applied  6 CHAPTER 1 Introduction to Evolutionary Anthropology research could involve planting various primate food trees in the remaining forest. In this way, I could determine whether the addition of specific food trees increased primate diversity. These research paradigms are directly relevant to formulating and testing scientific theory. What's a Theory? A scientific theory is a well-substantiated explanation of some aspect of the natural world that incorporates facts, laws, predictions, and tested hypotheses. A scientific theory Common theory is very different from a common theory. For example, I have a common theory that I An idea based only on always pick the slowest lineup to pay for items at a grocery store. Presumably, I have conjecture or personal opinion. sufficient data to support my theory because I have been to grocery stores hundreds of times. Is my common theory supported by enough data to form a scientific theory? No! I need to set up a series of experiments to test the hypothesis that I consistently have longer wait times than other patrons in grocery stores. In this experiment, I would need to control for interpersonal differences in grocery quantities, unloading times from carts, cashier speed, payment methods, and so on. As you can see, things get rather detailed when someone conducts hypothesis testing in science. Therefore, unlike a common the- ory, ascientific theory is a widely accepted set of ideas that produce hypotheses that can be tested and refined by the scientific community. What's a Hypothesis? A hypothesis is a testable statement about the natural world that a researcher uses to Inference A process build inferences and explanations. Before conducting an experiment, a scientist evaluates of reasoning in which and defines specific aspects of each hypothesis. From there, a scientist ensures that each a conclusion is derived from one or more hypothesis is falsifiable. Wait a second! You may be thinking that scientists are supposed facts. to prove, not disprove, their hypotheses. This is not the case. A simple example can illus- Falsifiable A study trate the critical importance of falsifiable hypotheses. Hypothetically, someone could sug- design that enables gest that giant, sentient cucumbers from an alternate universe brought the first life forms the researcher to to Earth and other planets in our galaxy. The research should not proceed because, in make observations that disprove a part, the hypothesis is not falsifiable — there is no way to test whether this is or is not the hypothesis. case. Specifically, you cannot falsify the existence of an alternative universe in evolution- ary anthropology, and there are no existing data to support the existence of giant, sen- tient cucumbers capable of interstellar travel. Thus, a hypothesis is not an "educated guess." A scientist uses observations from previous research to formulate and then test a hypothesis. For example, each year I teach a large course on introduction to anthropol- ogy. also I advise students on their study habits. Based on my observations, I could hypothesize as follows: If student grades in class are related to studying time, then people who study for longer time periods will have a higher final grade. An alternative hypo- thesis could be this: If student grades in class are related to studying quality, then people who have better study periods will have a higher final grade. Each hypothesis is falsifi- able because I can collect data on the study habits of the students and their final grades. I could also set up some experiments to test my hypotheses using the scientific method. The Scientific Method Evolutionary anthropologists employ the scientific method as often as possible in their research. The scientific method involves investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge (Cohen and Nagel, 1934). The scientific method generally involves five sequential processes: (1) observa- tion of the phenomena, (2) formulation of a hypothesis concerning the phenomena, (3) development of methods to test the validity of the hypothesis, (4) experimentation, and (5) a conclusion that supports or modifies the hypothesis. Data collected by a  Development of Evolutionary Concepts 7 scientist must be repeatable, observable, empirical, and measurable. The scientific method involves collecting quantitative data, which is information sometimes referred Quantitative data Information measura- to as "hard" or numerical in nature, and qualitative data, which is information on just ble or quantifiable on about anything that is non-numerical in nature. For example, a medical anthropologist a numeric scale, such can interview study subjects suffering from various parasitic illnesses. Because there as body mass or the number of primate is no direct, empirical means of measuring discomfort, the researcher may collect species in a protected area. qualitative data on pain levels (by asking people to evaluate it as low, moderate, or extreme). Conversely, the researcher could collect quantitative data on the number and kinds of parasites found in the blood and fecal samples of the local people. Qualitative Information data based on observations that cannot be reduced to numerical expression. Development of Evolutionary Concepts Before we get into modern evolutionary theory, it's important to have a short, historical review of the people that influenced the development of evolutionary concepts. Histori- ans trace ideas on biological evolution back as far as 2600 years ago in ancient Greece and Asia, to the works of Aristotle and Zhuangzi. For example, Aristotle's observations of the anatomy of various aquatic mammals and fish were thousands of years ahead of their time. Almost 2400 years ago, Zhuangzi suggested that living things have the power to transform themselves to adapt to their surroundings. In 18th-century Europe, a series of monumental changes occurred in scientific explorations and discoveries related to biological evolution. Historical Contributors Carl Linnaeus (1707-1778) was a Swedish physician and botanist, with a strong interest Botanist A scientist who studies plants. in classifying plants and animals (Figure 1.2). Often referred to as "the father of modern taxonomy," Linnaeus began his work with forays into local gardens, expanded into Classify tific methodTheof scien- placing remote areas of Sweden, and also received collections of animals from distant lands, including primates from equatorial regions of the world. Two of Linnaeus's most impor- an organism tem based on inorder a sys-by tant contributions to modern science are his taxonomic system and the binomial nomen- classes or categories. clature, which is a method scientists use tonjxQe plants_and animals in descriptive Latin terms. Linnaean taxonomy classifies all living things in a ranked hierarchy, from the Taxonomy The the- highest and most generalized category (a domain) down to the species level. Despite ory and practice describing, of naming, and classifying extant recent revisions to Linnaeus's classification levels, the basics of his system are still in use and extinct organisms. today. In the binomial nomenclature system, genus and species are written only in Latin. Scientists use Latin because it is no longer spoken, except by scholars, and therefore Binomial nomencla- will not change over time. In addition, the typeset for the font should be offset (italics or method tureforThe scientific assigning underlined) from the main text because the writer is using a different language. In evolu- names to species and tionary anthropology and biology, the first letter of the genus is capitalized while the first letter of all other words is in lower-case letters. For example, the binomial nomenclature Genus (pi. genera) for humans is Homo sapiens. Thus, we are in the genus Homo (human) and our species Agenera. taxonomic group of designation is sapiens (wise). Linnaeus believed that he was simply organizing God's species exhibiting creations because at that time, there was no treatise on biological evolution. similar characteristics. Georges-Louis Leclerc (1707-1788) was a French aristocrat, mathematician, and naturalist. Although Leclerc contributed to various scientific fields, one of his most notable contributions to evolutionary concepts was his monumental 36-volume Histoire Natural history Naturelle (1749-1788). This remarkable series of books described everything known The study of animals, about natural history at that time. For example, some of his ideas formed core concepts in what would eventually become the modern science of biogeography (Brown and plants, and minerals. Gibson, 1998), which is the study of where organisms live, at what abundance and why Biogeography scientific study of The they're there or not there. Leclerc's other primary contribution to the development of the geographic distri- evolutionary concepts was the idea that species changed and evolved after they moved bution oforganisms.  CHAPTER 1 Introduction to Evolutionary Anthropology Figure 1.2 Nineteenth-century painting of Carl Linnaeus, dressed in the traditional Lapp costume of Scandinavia. He is holding one of his favourite plants (Linnaea boreali), which was named in his honour. away from the place where they were created. This idea is broadly similar to Charles Darwin's Theory of Natural Selection. Jean-Baptiste Lamarck (1744-1829) was also French, a decorated soldier, and, later, an academic. Like Linnaeus, Lamarck was fascinated by the taxonomic classification of plants and animals. His major contribution to evolutionary concepts was a reformulation and specification of a very old idea on how organisms change. Lamarck suggested that individuals lose those characteristics they do not use and develop useful characteristics, and that individuals can pass on these characteristics (or lack thereof) to their offspring. He believed that these changes were the result of an unknown nervous fluid. Moreover, Lamarck theorized that environmen- tal changes could alter behaviour and biological organs. For example, application of Lamarck's ideas would mean that the excessively large muscles (the acquired character) developed by a professional athlete, such as the wrestler Hulk Hogan, must pass on to his offspring (inheritance of the acquired character). Clearly, Hulk Hogan's increased musculature is an acquired trait and not a heritable trait. Modern biologists have Comparative anatomy The study labelled these ideas by a variety of terms, including Lamarckism, the theory of "inheri- of anatomical features tance ofacquired characters," and "soft inheritance." Although Lamarckism is no of animals of different longer accepted by modern biologists, they agree that his published works were integral species. to the development of evolutionary concepts. Paleontology The Georges Cuvier (1769-1832) was another aristocratic French naturalist. Cuvier's stud- study of fossilized life ies and publications on structural similarities and differences between organisms helped forms. establish the scientific disciplines of comparative anatomy and palaeontology. These fields  Development of Evolutionary Concepts 9 compare and contrast tissues of living and extinct organisms. He contributed to the devel- opment ofevolutionary concepts through his work on the comparative anatomy of extant and extinct mammals. Although modern science accepts extinction as integral to evolu- tionary processes, in Cuvier's time his idea that extinction has occurred in some animals was in direct opposition to the widely accepted religious concept of fixity of species, which Fixity of species A is a purely religious idea that a Supreme Being created all living things and that no theory that derives from Biblical creation, changes have occurred since the moment of creation. Ideas about the fixity of species in which each living assert, quite incorrectly, that organisms do not change (evolve) or go extinct. Cuvier thing has always existed and will always championed a controversial idea known as catastrophism, which, among many other things, states that the surface of our planet originated suddenly in the past by geological exist by God's acts of creation. processes very different from those currently occurring. A key biological element of cata- Catastrophism The strophism ithat s it allows for changes in organisms but does not refute Biblical interpre- idea that catastrophic tations ofthe Earth's age. The prevailing view of contemporary European theologians events altered geologi- and religious authorities was that the planet was only 5700 years old. Because the cal features and caused the extinction of plants Catholic Church in 18th-century Europe wielded enormous political power, going and animals. against any of its major teachings was a perilous undertaking. However, Cuvier carefully avoided invoking a Biblical flood as the source of catastrophism, suggesting instead that there were multiple catastrophic events. In fact, he was strongly critical of contemporary evolutionary concepts, such as those proposed by Lamarck. Therefore, Cuvier's major contribution to evolutionary concepts was his assertion that species go extinct. James Hutton (1726-1797) was a Scottish naturalist and geologist. He made many contributions to the founding of geology as a science. Hutton proposed that successive Geology The upheaval and erosion of sedimentary rock had been occurring for millions of years and scientific study of the Earth, what it is made would continue to occur forever. Hutton's ideas would eventually form important com- of, and how it changes ponents ofa school of thought known as uniformitarianism, which is a geological principle over time. that holds that the Earth was formed and has evolved through the same natural geological School of thought processes operating today. Unfortunately, Hutton's complex writing style prevented his A group of people published work from receiving the public attention and acclaim he richly deserved. united in their shared belief in some ideas or Charles Lyell (1797-1875), another Scottish geologist, made numerous important concepts. contributions to geology, particularly in the fields of stratigraphy (the scientific study of how rock layers form) and glaciology (the study of how glaciers form). He was an Uniformitarianism enthusiastic field geologist, making many trips throughout Europe and even to North A theory that natural America. LyelPs three-volume Principles of Geology (1830-1833) greatly improved processes, such as ero- sion, operating in the access to and support for uniformitarianism. Before publishing his own thoughts past are the same as on biological evolution, one of LyelPs greatest, albeit indirect, contributions to the those that operate in the present. development of evolutionary concepts was his influence on young natural historians in Europe, such as Charles Darwin. Stratigraphy The study of rock layers relationships (strata) and theamong Charles Darwin and the Theory of Natural Selection them. Charles Darwin (1809-1882) was an English geologist and naturalist (Figure 1.3). The son and grandson of wealthy country doctors, Darwin entered medical school in hopes Glaciology The of continuing the family medical tradition. Though uninterested in medical studies, he study of glaciers and was fascinated by stories about the tropical forest told to him by John Edmonstone, otherenanatural involving phenom- ice. a freed slave from Guyana in South America. Darwin also spoke regularly with local authorities on zoology, taxonomy, and basic concepts in biological evolution. He spent Zoology tific study ofTheanimals. scien- considerable time in the countryside collecting insects, a craze among British naturalists of the period. Not surprisingly, Darwin failed to progress beyond his second year of medical school. He then enrolled in theology at Cambridge University. He spent most of his free time with friends, collecting insects, learning natural history from local authorities, and reading natural history books. Despite these extracurricular activities, Darwin managed to complete his degree. Rather than immediately taking his holy vows, Darwin joined an expedition to survey geological formations in Wales. While A 10 chapter i Introduction to Evolutionary Anthropology Figure 1.3 A photograph of Charles Darwin in his later years (c. 1869). Darwin was in Wales, two of his Cambridge professors, John Henslow and George Peacock, recommended him for the unpaid position of naturalist aboard the HMS Beagle. The Beagle was to set sail for a two-year survey of South America. Darwin was eventually awarded the position after cajoling his father for support and following interviews with the ship's captain. You can imagine his excitement to finally fulfill his dreams of exploration and discovery! The two-year trip extended to almost five years, as the HMS Beagle and her crew visited the eastern and western coasts of South America, the Galapagos Islands, Australia, various islands in the Indian Ocean, and South Africa. While at sea, Darwin read whatever natural history and geology books he could acquire, including LyelPs Prin- ciples ofGeology. Darwin spent much of his time on land, exploring geological forma- tions and collecting thousands of plant and animal specimens. You should note that at this time there were no antibiotics, water filters, or even mosquito repellents. Darwin spent months in environments that challenge even the best-prepared modern explorers and scientists. He made detailed notes on everything he saw and collected. Whenever possible, Darwin sent his collections and notes back to John Henslow at Cambridge Uni- versity, who made these materials available to a select group of scientists. Consequently, Darwin was a respected naturalist on his return to England in 1836. In 1839, he married one of his cousins, Emma Wedgwood, and settled into the life of a gentleman researcher. Darwin applied himself to determining how species evolved. His research was not composed solely of analyzing dead animals and fossils. Darwin also spoke with anyone knowledgeable about natural history, from dog and pigeon breeders to luminaries in the fields of geology and zoology (e.g., Charles Lyell). He also collaborated with expert naturalists in examining his specimens and categorizing them into distinct species. A bird  11 Development of Evolutionary Concepts expert studying Darwin's bird collection from the Galapagos Islands revealed that the birds represented 12 closely related species. Darwin theorized that one bird species must have arrived on the Galapagos from the mainland, and had then been altered in some way to eventually become different species. Darwin also read books on economics, such as Malthus's An Essay on the Principle of Population. Malthus proposed that human populations could potentially grow at geometric rates whereas food supplies can only increase at an arithmetic rate; he concluded that death, disease, and natural restraint limit human population growth. In other words, many more individuals are born than can possibly survive. Darwin applied certain aspects of Malthus's ideas about competition and checks to human population growth to animals in nature. Combining Malthus's the- ories with observations he made about the ability of animal breeders to use selective breeding to alter the physical form and behaviour of animals, Darwin formulated ideas about how nature selects for traits in animals. He reasoned that nature selects for or against individuals in the natural world — favourable variants or traits of individuals of a species should enable some to better compete in nature. By selection Darwin meant that the environment chooses certain physical aspects of an organism, so that some individu- als are more likely to survive than others. Thus, if these favourable variants are passed on to offspring, then successive changes over an immensely long time will result in the formation of new species. Less favourable variants and species will disappear. Darwin had formulated the basics of the theory of natural selection! Years passed between Darwin's first notions on natural selection and the publication of his complete theory. He initially shared only limited aspects of his ideas in letters to select researchers, such as Joseph Dalton Hooker, a famous English explorer with an interest in botany. Darwin's reticence stemmed predominantly from Botany The scientific concerns about rejection of his ideas by other scientists, such as Charles Lyell. Lyell study of Plants- was, at that time, strongly opposed to evolutionary ideas similar to those Darwin was working on. In fact, some of the most powerful and influential naturalists were adamantly opposed to alternatives to Lamarckism. To avoid conflict, Darwin published books about his trip aboard the HMS Beagle and about the zoology of barnacles. He conducted his experiments, engaged in friendly debates with his colleagues about biological evolution, and only secretly worked on a paper describing his theory on natural selection. However, as publication of his theory approached, Darwin's quiet life as a naturalist and country squire was about to change dramatically. In the summer of 1858, Darwin was shocked by the contents of an unpublished essay by Alfred Russel Wallace. Wallace (1823-1913) was a British naturalist and explorer who earned his living collecting and then selling organisms from the tropical forests of South America and Southeast Asia. In his essay, Wallace described ideas very similar to those in Darwin's theory of natural selection! Darwin finally felt obliged to present his ideas on biological evolution and natural selection to the scientific commu- nity. In 1858, papers by Darwin and Wallace were read at a special meeting of the Linnean Society in London, which created considerable excitement among the atten- dees. On November 22, 1859, 1250 copies of Darwin's On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life went on sale in London. Most copies of the book sold on the first day. Today, many scientists consider On the Origin of Species to be one of the greatest works of science ever published. Darwin spent the remainder of his professional life revising On the Origin of Species and publishing books on various scientific topics. What did Darwin say in On the Origin of Species} Darwin synthesized his field experiences, discussions with animal breeders, experiments, and the work of others into two broad ideas on how species evolve. First, Darwin theorized that all extant and extinct species share a common ancestry, which he eventually called The Tree of Life (Figure 1.4). Closely related species have a more recent common ancestor, while 12 chapter i Introduction to Evolutionary Anthropology Figure 1.4 A page from Darwin's notebooks, showing his first attempts to illustrate an evolutionary tree, which he termed The Tree of Life. more distantly related species have an older common ancestor. Thus, the supernatural creation of life and the spontaneous creation of species by Lamarckian mechanisms are unnecessary. Darwin saw the process of species formation as a slow, gradual accumulation of slight variations in traits of individuals. Second, Darwin laid out his compelling argument for the power and scope of natural selection. He described his observations on how humans create new variants of dogs though selective breeding, and extended this human selection for domesticates to how nature selects for certain characteristics of individuals, which then compete amongst each other for access to food and mates. Darwin elegantly wrote, Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relations to other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring. The offspring, also, will thus have a better chance of surviving, for, of the many individuals of any species which are periodically born, but a small number can survive. I have called this principle, by which each slight variation, if useful, is preserved, by the term of Natural Selection, in order to mark its relation to man's power of selection. (1859, p. 61) It is impossible in one paragraph to summarize On the Origin of Species. Furthermore, it is beyond the scope of this book to review the considerable differences between how Darwin and Wallace saw natural selection operating. Darwin's knowledge and descriptions of biological diversity were remarkable, even by modern standards. Despite the limitations of 19th-century science, Darwin made accurate  13 Development of Evolutionary Concepts predictions about many biological facts that we now know only because of decades of research. On the Origin of Species is a remarkably detailed but easily read piece of science, and well worth the time to read and enjoy. Misconceptions about Darwin's Ideas There are some common misconceptions about Darwin's published works. Darwin did notx^riginatejhe phrase, "survival of the fittest." This phrase was the creation of Herbert Spencer, a social philosopher and contemporary of Darwin. Spencer introduced the phrase in Principles of Biology (1864) after reading Darwin's On the Origin of Species. While Darwin did use it as a synonym for natural selection in the final editions of his book, modern biologists do not use "survival of the fittest" because it was originally intended to apply to human societies and because Spencer favoured Lamarckian concepts over natural selection. It is imperative that you under- stand that societies change; they do not experience biological evolution. Misguided attempts to apply Darwin's theory on natural selection to human societies have resulted in Social Darwinism and the atrocities of the Holocaust and Rwandan Social Darwinism The misguided appli- genocide. Proponents of Social Darwinism hold that the strongest or fittest individu- cation ofthe concepts als should survive and flourish in society, whereas weak and unfit individuals should of natural selection be allowed to die. Moreover, "survival of the fittest" implies that organisms gain evo- and biological evolu- tion to the historical lutionary success only by being competitive and aggressive (Figure 1.5), contradicting development of human societies, Darwin's notion that morality has a role to play in human evolution, and that coop- eration and other positive social behaviours can also result in evolutionary success placing special (Chapman and Sussman, 2004). Evolutionary anthropologists also criticize colloquial emphasis of "survivalonofthetheidea use of this phrase, which incorrectly emphasizes the physical attributes of an organ- ism (e.g., body size, ferocity, and armament). In evolutionary anthropology and biol- ogy, fitness is a very different thing (Futuyma, 1998). Fitness The average contribution of an allele or genotype Darwin's ideas on natural selection and biological evolution resulted in consider- fittest." able controversy among religious conservatives. These issues tend to revolve around to succeeding the origins of life, the supposed impacts of Darwin's ideas on religious doctrine, and Darwin's personal views on religion. Some people conflate Darwin's views on the generations. origins of life with the origins of the universe. Darwin's works refer to the evolution of biological systems, not to stellar and galactic phenomena. Second, some religious groups hold misconceptions about how Darwin's ideas on natural selection and biolog- Creationism The ical evolution relate to their faith. Creationism became particularly prevalent in secular settings immediately after the publication of On the Origin of Species. Most creation- largelyall Christian that belief life was created ists apply a literal interpretation of the Bible to the origins of life, particularly the parts by a supernatural deity dealing with God's creation of the universe. For example, Young Earth Creationists existence Cod), (typically of whichthe is hold that the earth is only 10 000 years old, rather than the geological estimate of 4.5 billion years. Consequently, creationists see Darwin's work as an attack on funda- presupposed. mental aspects of their belief systems, requiring them to oppose his ideas. The weight of decades of scientific evidence supporting biological evolution led many people to abandon creationist ideas, and to understand that creation themes of the Bible repre- sent symbolic rather than literal truths (Futuyma, 1982). Some fundamentalist Christians refused to accept that Darwin's ideas have noth- ing to do with their personal faith. Consequently, these diehard believers morphed Intelligent design creationism into something called intelligent design. Intelligent design or "scientific The belieflargely Christian that living things creationism" represents an attempt to discredit the work of Darwin and other evolu- tionary anthropologists. This belief system lacks scientific support for an intelligent occur because of intel- creator or design; adherents simply seek to discredit Darwin's ideas. For example, ligent cause, not as a result of undirected despite lacking any data to support the existence of "scientific creationism," some peo- ple advocate teaching this purely religious idea as an alternative to evolution in biology processes, lution and such naturalas evo- classes in publicly funded school systems. These misguided attempts have failed to gain selection. 14 chapter i Introduction to Evolutionary Anthropology Figure 1.5 Satirical representation of misconceptions regarding the concept of "survival of the fittest."  15 Development of Evolutionary Concepts traction in most school boards, and they have been consistently dismissed by the courts as a duplicitous means of promoting conservative religious opinions. The fact is that Darwin's ideas on biological evolution do not conflict with religion. Why? Because biological evolution deals with biology whereas religion relates to theology. In Theology The study other words, religion has no role to play in biological evolution, or vice versa. Thus, of religion from a reli- when contacted by a young student about the seeming conflict between natural selec- gious perspective. tion and faith, Darwin wrote, "Science has nothing to do with Christ, except insofar as the habit of scientific research makes a man cautious in admitting evidence" (darwin-online.org.uk). Contrary to what can be found on creationist websites, Darwin was not an atheist; he was an avowed agnostic. Darwin's personal religious beliefs were complex and Agnostic A person holding the belief that changed throughout his life. Although circumstance and Darwin's faith led him to try Cod is unknown and to join the Anglican clergy, his scientific discoveries and the early death of one of his unknowable. beloved children resulted in his rejecting Christian beliefs. Finally, he did not undertake a deathbed conversion to Christianity. You may be surprised to learn that Darwin did not use the term biological evolu- tion at all in On the Origin of Species. The closest he came to doing so was in the last sentence of the book: There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved, (p. 490) Darwin did support some aspects of Lamarckism. In fact, he followed Alfred Wallace's suggestion to use Lamarck's explanation of how traits could move from one generation to the next. In later publications, Darwin hypothesized that gemmules passed on traits from one generation to the next. He suggested that gemmules are parti- cles of inheritance produced by organs and carried in the blood. However, experiments by contemporary researchers, including one of Darwin's half-cousins, failed to prove the existence of gemmules. Neither Darwin nor any contemporary scientist knew the biological mechanisms for hereditary variations (i.e., genetics). In other words, no one at that time knew how traits were passed from one generation to the next. A monk in Eastern Europe provided the answer to this vital piece of the evolutionary puzzle. Introduction to Mendelian Genetics Gregor Mendel (1822-1884) was a monk in what is the present-day Czech Republic. Mendel was fascinated by physical variations in plants. In his monastery, Mendel experi- mented with seven physical characteristics of the common pea plant (Pisum sativum). For example, his plants produced either yellow or green pods but not yellowish-green pods, purple flowers or white flowers, round seeds or wrinkled seeds, and so on (Figure 1.6). Pea plants are ideal study subjects for inheritance research because a researcher can manipulate their reproduction and maintain large numbers of plants in a small area. Pea plants have both male and female reproductive organs, so each plant can either self-pollinate or cross-pollinate with another plant. Mendel's methods were simple but illuminating. First, he used selective breeding on pea plants so that they always produced only one variant of each trait (e.g., either yellow or green pods). Next, he cross-pollinated the pure plant strains and observed the physical traits of the offspring. Thus, Mendel allowed the pure-breeding plants to pollinate each other, such that the yellow pod plants bred with the green pod plants. The first generation of plants grown from this cross- breeding exhibited only one of the two physical characteristics. In our example, the first offspring always produced yellow pods. Finally, he allowed these offspring to self- pollinate, which produced a second generation of plants. In this second generation of 16 chapter i Introduction to Evolutionary Anthropology Figure 1.6 White flower on a common pea plant. © Dreamstime plants, Mendel observed that the physical characteristics were consistently expressed by a ratio of approximately three to one (3:1). So, three out of every four offspring exhib- ited yellow pods whereas only one of the four had green pods. Mendel concluded three things about physical variation and heredity. First, an organism's physical traits pass from one generation to the next by "units" or "factors." Second, each individual inherits one "factor" from each parent. Third, a trait may not show up in an individual, although the trait can still be passed from one generation to the next. Mendel reasoned that one "factor" must "mask" another. With considerable pride and excitement, he published results of his experiments in a scientific journal. Unfortunately, naturalists either derided or ignored his conclusions. Mendel's work was largely forgotten until European botanists rediscovered it in the early 20th century. Mendel is now referred to as the "father of genetics" because he discovered the mechanisms of inheritance and because his work led directly to studies that established that biological evolution is the result of genetic variations. In the following section, we explore what really happened in Mendel's experiments.  Development of Evolutionary Concepts 17 What Actually Happened in Mendel's Experiments? In time, modern scientists determined what exactly was happening in Mendel's pea plants. The varieties of Mendel's pea plants that are physically distinguishable are now called phenotypes, the observable traits of an organism (Figure 1.7). For example, the Phenotype Observ- pod colour phenotypes were yellow and green. We also know that what he called able traits or character- istics ofan organism. "factors" are actually genes. The genotype represents the specific genes in an individual or population, whether or not they are expressed physically. In Mendel's experiment, Genes tional units Basic, func- of heredity. each of the phenotypes was based on a specific genetic code, such as a gene that produces pod coloration. The question arises here as to how some physical features Genotype Genetic (phenotypes) could seem to skip a generation. You may be familiar with this pattern makeup of an in that many people describe certain familial characteristics observable in parents organism. passing through offspring to show up again in their grandchildren. In fact, Mendel struggled with how to explain this "skipping of generation" phenomenon in his pea Allele One of several plants. In the end, Mendel concluded that there rmusTrJe two alleles (different forms forms of the same of the same gene) for each physical characteristic: for example, one allele for yellow pods and one allele for green pods. We can represent the allele for yellow pods with an upper-case Y and the allele for green pods with a lower-case y. You will see in just a moment that there is a purpose in using upper and lower case. In Mendel's model, each plant inherits one allele for each characteristic from each gene. parent plant. Modern scientists have devised terms for describing these different alleles and how they relate to each other and the physical expression of traits. A homozygous Homozygous Identi- condition occurs when an individual organism ha