This volume is based on the National Academy of Sciences' Colloquium on the Tempo and Mode of Evolution. The articles appearing in these pages were contributed by speakers at the colloquium and have not been independently reviewed. Any opinions, findings, conclusions, or recommendations expressed in this volume are those of the authors and do not necessarily reflect the views of the National Academy of Sciences.

The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.

Library of Congress Cataloging-in-Publication Data

Tempo and mode in evolution: genetics and paleontology 50 years after Simpson/Walter M. Fitch and Francisco J. Ayala, editors, for the National Academy of Sciences.

p. cm.

Includes bibliographical references and index.

1. Evolution (Biology) 2. Genetics. 3. Paleontology. I. Fitch, Walter M., 1929– . II. Ayala, Francisco J., 1934– . III. National Academy of Sciences (U.S.)

QH366.2.T46 1995 94-37675

575—dc20 CIP