Edited by John R. Baker

Contributors:

John R. Baker, E. B. Ford, Alister Hardy, Bernard Kettlewell, P. L. Pearson, Vernon Reynolds, Mark Richmond, H. N. Southern, T. Stanley Westoll

When this book was first published more than thirty years ago, Professor J. B. S. Haldane wrote of it that 'for many years to come it will be absolutely indispensable for any serious study of the questions with which it deals.' This was true enough; but in 1963 Sir Julian felt it desirable to bring it up to date in a second edition by adding a long new Introduction. The stock of the latter edition has now become exhausted, and the rapid increase in knowledge in the last decade has made it necessary to modernise it once more. It has been decided that new matter should not be inserted in a book that has gained for itself a special place in biological literature. Instead, a team of nine authorities on particular branches of the subject has written another new Introduction, with an accompanying Bibliography. Taken together, the latest Introduction and Bibliography will guide the reader to most of the important advances that have been made in recent years in the study of evolution, while the original text and Sir Julian's earlier Introduction maintain their full value. Among the many subjects discussed at some length in the new Introduction are evolution in our own times, bacterial genetics, the dating of the past, the evidence from chromosomes on man's relationship to particular pongids and what Sir Julian has called the 'psychosocial evolution' of man.

PREFACE TO THE FIRST EDITION

In 1936, I had to find a subject for the presidential address to the Zoology Section of the British Association. After some hesitation, I chose "Natural Selection and Evolutionary Progress", since it seemed to me that these were two interrelated topics of fundamental biological importance, yet on which much misapprehension existed. Even among professional zoologists the modern conception of natural selection and its mode of operation is quite different from that of Darwin's day, but much of the research on which the changed outlook is based is so recent that the new ideas have not spread far. The idea of evolutionary progress, on the other hand, has been undeservedly neglected. Thus it seemed to me valuable to attempt to give a broad account of the two concepts and their relation to each other.

The result exceeded my expectations. So many of my colleagues expressed interest and the wish that the address might be available in more extended and more permanent form, that I decided to essay expanding it into a book.

The result is the present volume. I am fully conscious of its limitations and imperfections, but I believe that it will serve a useful purpose. The writing of it has so much clarified my own thinking, and the discussion of the problems that arose with colleagues has resulted in so many ideas and points of view which were novel both to them and to myself, that I am encouraged to believe it will be of general service. I also feel sure that a classification and analysis of evolutionary trends and processes as observed or deduced in nature, and the attempted relation of them to the findings of genetics and systematics, is of first-class importance for any unified biological outlook; and since others better equipped than I seem reluctant to attempt the task, I have tried my hand at it.

I owe a great deal to J. B. S. Haldane's The Causes of Evolution; but though our books overlap, they differ considerably in scope and treatment. Dobzhansky's, Waddington's, and Goldschmidt's valuable and distinctive books did not appear until much of the present volume was already in proof; but I have tried to take advantage of them where possible. My debt to R. A. Fisher's work is obvious: Fisher has radically transformed our outlook on the subject, notably by pointing out how the effect of a mutation can be altered by new combinations and mutations of other genes. Any originality which this book may possess lies partly in its attempting to generalize this idea still further, by stressing the fact that a study of the effects of genes during development is as essential for an understanding of evolution as are the study of mutation and that of selection. I may also claim that taxonomic data have not previously been analysed on so large a scale in the light of modern genetic and evolutionary views. Equally obvious is my debt to the Morgan school and to Goldschmidt; but clearly this would apply to any modern book dealing with evolution.

with the basic principles of Mendelian heredity and the major groups of the animal kingdom. With this equipment, the layman interested in biology will, I hope, find the book suited to his needs, though I hope that it will appeal mainly to professional biologists interested in the more general aspects of their subjects.

I would like to record my special gratitude to Mr. E. B. Ford, of Oxford, who has read the book in typescript, and with whom I have discussed all the genetic problems involved: he has been fertile in suggestion and prodigal of assistance. To Professor L. T. Hogben, F.R.S., I owe several valuable suggestions on the evolution of species. I should also like to thank Professor R. A. Fisher, F.R.S., Professor H. J. Muller, Dr. C. D. Darlington, F.R.S., Professor Hale Carpenter, Dr. W. B. Turrill, and Mr. Moy Thomas for help and advice; and particularly Mr. James Fisher for valuable assistance in revising the book for press.

The time is ripe for a rapid advance in our understanding of evolution. Gcnetics, developmental physiology, ecology, systematics, paleontology, cytology, mathematical analysis, have all provided new facts or new tools of research: the need to-day is for concerted attack and synthesis. If this book contributes to such a synthetic point of view, I shall be well content.

THB ZOOLOGICAL SOCIBTY, LONDON
March 1942

INTRODUCTION TO THE THIRD EDITION

This Introduction has been written by my old pupils and colleagues at the Oxford Department of Zoology and others invited to contribute by Dr. John Baker. I wish to express my deep gratitude to them all.

JULIAN S. HUXLEY

Editor's foreword. When the stock of the second edition of this book was exhausted, Sir Julian Huxley asked some of his former pupils to help in the preparation of a third. As a result, five zoologists met Mr. Rayner Unwin to discuss what should be done. It was agreed that new matter should not be inserted in a book that had gained for itself a special place in biological literature. It seemed better to do what Sir Julian had himself done in preparing the second edition, namely, to leave the work intact and bring it up to date by adding a new Introduction. This suggestion received Sir Julian's approval. The zoologists present at the meeting agreed to contribute to the new Introduction and one of them was appointed Editor.

It was recognized that if an Introduction worthy to stand between the covers of Sir Julian's book were to be produced, it would be necessary to call in others to deal with those branches of the subject in which none of the original group had special knowledge. The team was therefore expanded by the inclusion of authorities on various topics that would otherwise have had to be left untouched. The nine contributors were not asked, however, to perform the task-impossible within the imposed limit of space-of dealing with every important advance within their own fields; on the contrary, they were encouraged to follow their own bents as they wished, provided that they made references to papers or books that would supply wider information.

This Introduction is not just a set of independent reviewarticles. It is intended to be read as a whole, divided only by sub-titles. Many readers, however, will want to know who was the author of each contribution, and this information is therefore given here.

Emeritus Professor E. B. Ford, Deparnnent of Zoology, Oxford University: "The mechanism of evolution" (p. xiv)
Professor Mark Richmond, Department of Bacteriology, Bristol University: "Minobial genetics and its relevance to evolution" (p. xxvi)
Dr. H. N. Southern, Department of Zoology, Oxford Universiiy: "Evolutionary ecology" (p. xxxii)
Dr. Bernard Kettlewell, Department of Zoology, Oxford University: "The evolution of industrial melanism in Lepidoptera" (p. xl)
Emeritus Professor Sir Alister Hardy, Department of Zoology, Oxford University: "Behaviour as a selective agent in evolution" (p. xliv)
Professor T. Stanley Westoll, Deparnnent of Geology, University of Newcastle upon Tyne: "Evidence from palaeonrology" (p. xlviii)
Dr. John R. Baker, Department of Zoology, Oxford University: "The fossil Hominidae of East Africa" (p. lvii)
Dr. P. L. Pearson, Instituut voor Anthropogentica, Rijksuniversiteit te Leiden: "Man and pongids: evidence from chromosomes, bearing on their relationship" (p. Ixiii)
Dr. Vernon Reynolds, Anthropology Laboratory, Department of Human Anatomy, Oxford University: "The evolution of hominid social behaviour" (p. lxx)

An integrated bibliography of all the papers and books quoted by the nine contributors is printed on pp. 661-74 separately from St. Julian's lists on pp. 618-52 and 653-60

It was thought that those who took up this book for the first time in its third edition would not wish to be faced at the outset with two long Introductions. Sir Julian's Introduction to the second edition, which retains its full value today, ~is therefore placed after the main body of the text, on pp. 579-617

 

CONTENTS

Chapter 1: The Theory of Natural Selection
Chapter 2: The Multiformity of Evolution
Chapter 3: Mendelism and Evolution
Chapter 4: Genetic Systems and Evolution
Chapter 5: The Species Problem; Geographical Speciation
Chapter 6: Speciation, Ecological and Genetic
Chapter 7: Speciation, Evolution, and Taxonomy
Chapter 8: Adaptation and Selection
Chapter 9: Evolutionary Trends
Chapter 10: Evolutionary Progress