Australia and New Zealand boast an active community of scholars working in the field of history, philosophy and social studies of science. • Australasian Studies in History and Philosophy of Science' aims to provide a distinctive publication outlet for their work. Each volume comprises a group of essays on a connected theme, edited by an Australian or a New Zealander with special expertise in that particular area .. In each volume, a majority of the contributors is from Australia or New Zealand. O;mtributions from elsewhere are by no means ruled out, however, and are indeed actively encouraged wherever appropriate to the balance of the volume in question. Earlier volumes in the series have been welcomed for significantly advancing the discussion of the topics they have dealt with. The present volume will I believe be greeted equally enthusiastically by readers in many parts of the world. R. W. Home General Editor Australasian Studies in History and Philosophy of Science TABLE OF CONTENTS v FOREWORD PAUL GRIFFITHS / Introduction 1 SECTION ONE: BEYOND NATURAL SELECTION ELLIOTI SOBER / Models of Cultural Evolution 17 KIM STERELNY / Punctuated Equilibrium and Macroevolution 41 ROBIN CRAW / Margins of Cladistics: Identity, Difference and Place in the Emergence of Phylogenetic Systematics 1864-1975 65 SECTION TWO: CENTRAL CONCEPTS OF EVOLUTIONARY THEORY PAUL GRIFFITHS / Adaptive Explanation and the Concept of a Vestige 111 TIMOTHY SHANAHAN / Selection, Drift and the Aims of Evolutionary Theory 133 SECTION THREE: THE DEVELOPMENTAL SYSTEMS APPROACH