Genetics, Paleontology, and Macroevolution; Second Edition Jeffrey S. Levinton CAMBRIDGE UNIVERSITY PRESS Genetics, Paleontology, and Macroevolution Second Edition An engaging area of biology for more then a century, the study of macroevolution continues to offer profound insight into our under- standing of the tempo of evolution and the evolution of biological diversity. In seeking to unravel the patterns and processes that regulate large-scale evolutionary change, the study of macroevolution asks: What regulates biological diversity and its historical development? Can it be explained by natural selection alone? Has geologic history regulated the tempo of diversification? The answers to such questions lie in many disciplines including genetics, paleontology, and geology. This expanded and updated second edition offers a comprehensive look at macroevolution and its underpinnings, with a primary empha- sis on animal evolution. From a neo-Darwinian point of view, it inte- grates evolutionary processes at all levels to explain the diversity of animal life. It examines a wide range of topics including genetics and speciation, development and evolution, the constructional and func- tional aspects of form, fossil lineages, and systematics. This book also takes a hard look at the Cambrian explosion. This new edition pos- sesses all of the comprehensiveness of the first edition, yet ushers it into the age of molecular approaches to evolution and development. It also integrates important recent contributions made to our understanding of the early evolution of animal life. Researchers and graduate students will find this insightful book a most comprehensive and up-to-date examination of macroevolution. Jeffrey S. Levinton is a professor in the Department of Ecology and Evolution at the State University of New York at Stony Brook. This Page Intentionally Left Blank Genetics, Paleontology, and Macroevolution JEFFREY S. LEVINTON State University of New York at Stony Brook Second Edition PUBLISHED BY CAMBRIDGE UNIVERSITY PRESS (VIRTUAL PUBLISHING) FOR AND ON BEHALF OF THE PRESS SYNDICATE OF THE UNIVERSITY OF CAMBRIDGE The Pitt Building, Trumpington Street, Cambridge CB2 IRP 40 West 20th Street, New York, NY 10011-4211, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia http://www.cambridge.org © Cambridge University Press 2001 This edition © Cambridge University Press (Virtual Publishing) 2003 First published in printed format 1988 Second edition 2001 A catalogue record for the original printed book is available from the British Library and from the Library of Congress Original ISBN 0 521 80317 9 hardback Original ISBN 0 521 00550 7 paperback ISBN 0 511 01829 0 virtual (netLibrary Edition) For Joan, always Such stillness – The cries of the cicadas Sink into the rocks – Matsuo Basho, The Narrow Road of Oku Life don’t clickety clack down a straight line track It come together and it come apart. – Ferron, 1996 This Page Intentionally Left Blank Preface to the First Edition page ix Preface to the Second Edition xiii 1 Macroevolution: The Problem and the Field 1 2 Genealogy, Systematics, and Macroevolution 32 3 Genetics, Speciation, and Transspecific Evolution 81 4 Development and Evolution 157 5 The Constructional and Functional Aspects of Form 227 6 Patterns of Morphological Change in Fossil Lineages 285 7 Patterns of Diversity, Origination, and Extinction 367 8 A Cambrian Explosion? 443 9 Coda: Ten Theses 495 Glossary of Macroevolution 511 References 519 Author Index 587 Subject Index 605 Contents vii This Page Intentionally Left Blank I have so many things to write about, that my head is as full of oddly assorted ideas, as a bottle on the table is filled with animals. – Charles Darwin, 1832, Rio de Janeiro Evolutionary biology enjoys the peculiar dual status of being that subject which clearly unites all biological endeavors, while occasionally seeming to be nearly as remote from complete understanding as when Darwin brought it within the realm of materialistic science. Somehow, the basic precepts first proposed by Darwin have never been either fully accepted or disposed, to be followed by a movement toward further progress in some other direction. The arguments of today – the questions of natural selection and adaptation, saltation versus gradualism, and questions of relatedness among organisms – are not all that different from those discussed 100 years ago, even if the research materials seem that much more sophisticated. Darwin espoused thinking in terms of populations. His approach was open to experimentation, but this had to await the (re)discovery of genetics half a century later, before a major impediment to our understanding could be thrown aside. As it turned out, the rediscovery of genetics was initially more confusing than helpful to our understanding of evolution. The rediscovery of genetically transmissible discrete traits revived saltationism, and it took over a decade for biologists to realize that there was no conflict between the origin of discrete variants and the theory of nat- ural selection. In the twentieth century, the focus of experimentalists moved toward processes occurring within populations. But many of the inherently most fascinating questions lie at higher taxonomic levels, or at greater distances of relationship than between individuals in a population. The questions are both descriptive and mecha- nistic. We would like to know just how to describe the difference between a lizard and an elephant, in terms that would make it possible to conceive of the evolution- ary links between them. We are only now beginning to do this, principally at the molecular genetic level. Differences in nucleotide sequences are beginning to have more meaning at this level, especially because of the emerging knowledge of gene regulation. But we would also like to understand the mechanisms behind the evolu- tionary process at higher levels of morphological organization. This inevitably ix Preface to the First Edition [...]... editor, and her staff for seeing this second edition to press Joan Miyazaki was predictably the perfect partner and helped me in many ways with this project This Page Intentionally Left Blank CHAPTER 1 Macroevolution: The Problem and the Field The science of life is a superb and dazzlingly lighted hall, which may be reached only by passing through a long and ghastly kitchen – Claude Bernard The Process and. .. Process and the Field of Macroevolution The return of macroevolution The field of macroevolution embraces the excitement of seeking an understanding of the breadth of life We have long desired to know how best to describe the diversity of life’s forms and to explain how and why this diversity came to be No mystery is more intriguing than why we have amoebas and horses, or dandelions and palms The child’s... the macroevolutionary perspective, and that the neo-Darwinian movement and the Modern Synthesis somehow undermined our ability to understand the process of evolution and brought us to our present pass of misunderstanding The recent “born again” moves toward saltationism, and the staunchly ideological adherence to related restrictive concepts, such as punctuated equilibria, are great leaps backward and. .. not even be asked very seriously just a few decades ago 1 2 GENETICS, PALEONTOLOGY, AND MACROEVOLUTION Definition of the Process of Macroevolution I define macroevolution to free it from any dependence on specific controversies and, more importantly, to define a field derived from tributaries that have merged from many sources I define the process of macroevolution to be (Levinton 1983) the sum of those processes... phylogenetic relationships among taxa? What is the nature of evolutionary novelty and how do novel characters define the taxa we delineate? 4 GENETICS, PALEONTOLOGY, AND MACROEVOLUTION 2 How do genetic, developmental, and morphological components channel the course of morphological and genetic evolution? 3 What are the patterns of change and what processes regulate the rate of evolutionary change from one character... might also be studied (e.g., studying species, subfamilies, and families, as opposed to species, families, and orders) They are just conveniences whose ascending order of ranking may correlate with differences of response (e.g., Valentine 1969) On the other hand, some regard certain taxonomic levels as fundamental and 8 GENETICS, PALEONTOLOGY, AND MACROEVOLUTION of ontological significance Van Valen (1984)... as the smallest unit of consideration, though recent discoveries of molecular genetics muddle this a bit 10 GENETICS, PALEONTOLOGY, AND MACROEVOLUTION Population genetics usually sees the fate of genes in terms of their contributions to fitness and stochastic processes Complexities of genetic structure, such as epistasis and linkage, greatly complicate population genetic models Yet it is a legitimate... cephalopod eye Here, neo- MACROEVOLUTION: THE PROBLEM AND THE FIELD 13 Darwinians would stand firm in ascribing such an evolutionary process to natural selection working on the interactions of genes and the organism The Role of Type in Evolutionary Concepts Typology and evolution The problem of macroevolution has always been regarded as the problem of the origin and evolution of types and the present gulf... now-defunct hypotheses such as Lamarckism and orthogenesis But, most importantly, Sewall Wright, J B S Haldane, and R A Fisher laid the foundations for genetic analysis of traits and genetic changes in populations The power of nat- 16 GENETICS, PALEONTOLOGY, AND MACROEVOLUTION ural selection was discovered, starting from an initial report by Punnett (1915), and a debate arose about the relative importance... events and their frequency This point of view has made for an unfortunate battle royal, where victory would mean that the opposing group was irrelevant in evolutionary biology If the microevolutionists win, then there is no such thing as macroevolution If the macroevolutionists gain favor, then microevolution exists, but it is a minor part of a much larger set of 6 GENETICS, PALEONTOLOGY, AND MACROEVOLUTION . Genetics, Paleontology, and Macroevolution; Second Edition Jeffrey S. Levinton CAMBRIDGE UNIVERSITY PRESS Genetics, Paleontology, and Macroevolution Second Edition An engaging. questions lie in many disciplines including genetics, paleontology, and geology. This expanded and updated second edition offers a comprehensive look at macroevolution and its underpinnings, with a primary. come together and it come apart. – Ferron, 1996 This Page Intentionally Left Blank Preface to the First Edition page ix Preface to the Second Edition xiii 1 Macroevolution: The Problem and the Field