Climbing Mount Improbable 9780393039306, 0393039307, 9780393316827, 0393316823

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“A superb prose stylist, perhaps the best popularizer of science.”

—New York Review of Books

RICHARD

MOUNT IMPROBABLE

CLIMBING

MOUNT

IMPROBABLE

By

the

THE THE

BLIND

RIVER

Author

SELFISH

EXTENDED

THE

Original

Same

GENE PHENOTYPE

WATCHMAKER

OUT

drawings

OF

EDEN

by

Lalla Ward

x ota

Sage Boy colo

_a a, Peels

Copyright © 1996 by Richard Dawkins

Original drawings copyright © 1996 by Lalla Ward All rights reserved First American Edition 1996

Printed in the United States of America The texct of this book is composed in Centaur. Composition by Justine Burkat Trubey using Adobe Pagemeaker 6.0. Manufacturing by The Haddon Craftsmen, Inc.

Book design by Margaret M. Wagner

Library of Congress Cataloging-in- Publication Data Dawkins, Richard, 1941—

Climbing mount improbable / Richard Dawkins ; original drawings by Lalla Ward. , ett. Includes bibliographical references and index, ISBN 0-393-03930-7 1. Natural selection. 2. Evolutionary genetics, 3. Morphogenesis. L. Title. QH375.D376 1996 575.0162—dc20 96-19138

CIP

WW. Norton & Company, Inc. 500 Fifth Avenue, New York, butp: / /veww.wwnorton.com

NY.

WW. Norton & Company Lid., 10 Coptic Street, London WCLA 12345678990

10110

1PU

COLLEGE LIBRARY

For Robert Winston, good doctor and a good man

Contents

Acknowledgements

\

ix

Picture Acknowledgements

xi

I Facing Mount Rushmore 3 2 Silken Fetters 38 3 The Message from the Mountain 4 Getting off the Ground

73

108

5 The Forty-fold Path to Enlightenment 6 The Museum of All Shells

7 Kaleidoscopic Embryos

198

224

8 Pollen Grains and Magic Bullets 256 9 The Robot Repeater 276 IO ‘A Garden Inclosed’ 299 Bibliography 327 Index 333

138

Acknowledgements

THIS

Christmas

Lectures,

BOOK

GREW

televised

OUT

by the

OF

MY

BBC

ROYAL

under

INSTITUTION

the general

title

Growing Up in the Universe. I have had to abandon that title because at least three other books

have since appeared

with

almost

identical

names. Moreover, my book itself has grown up and changed, so it is

no

longer

fair to call it the

book

of

the

Christmas

Lectures.

Nevertheless I should like to thank the Director of the Royal Institution for honouring me with the invitation to join the historic lineage of Christmas Lecturers going all the way back to Michael Faraday. Bryson Gore of the Royal Institution, together with William Woollard and Richard Melman of Inca Television, influenced the lectures greatly, and traces of their influence will still be found in this greatly transformed and enlarged book. Michael Rodgers read and constructively criticized early drafts of more

chapters than are here printed, and advised decisively on the

reconstruction of the whole book. Fritz Vollrath and Peter Fuchs gave expert readings of Chapter 2, while Michael Land and Dan Nilsson

did the same for Chapter S. All four of these experts gave generously of their knowledge when I tapped it. Mark Ridley, Matt Ridley, Charles Simonyi and Lalla Ward Dawkins read the whole book in a late draft and provided helpful criticism and reassuring encouragement in needful proportions. Mary Cunnane of W. W. Norton and Ravi ix

ACKNOWLEDGEMENTS

Mirchandani of Viking Penguin showed generous tolerance and bighearted judgement as the book grew, took on a

life of its own and

finally shrank again to more manageable scope. John Brockman lurked encouragingly in the background, never interfering but always ready

with support. Computer experts are heroes, too often unsung. In this book I have used the programs of Peter Fuchs, Thiemo Krink and Sam Zschokke. Ted Kaehler collaborated with me in conceiving and writ-

ing the difficult Arthromorphs program. In my own suite of ‘watchmaker’ programs I have frequently benefited from the advice and help of Alan Grafen and Alun ap Rhisiart. The staff of the Zoological and Entomological Collections of the University Museum at Oxford lent

specimens and expert advice. Josine Meijer was a willing and resourceful picture researcher. My wife, Lalla Ward Dawkins, did the drawings (though not the layouts) and her love of Darwinian Creation shines

through every one of them. I should like to thank Charles Simonyi, not only for his immense generosity in endowing the post in Public Understanding of Science which I now hold at Oxford, but also for articulating his vision—

which coincides with mine—of the craft of explaining science to a large audience. Do not talk down. Try to inspire everybody with the poetry of science and make your explanations as easy as honesty allows, but at the same time do not neglect the difficult. Put extra effort into explaining to those readers prepared to put matching effort into understanding.

Picture

Acknowledgements

Drawings by Lalla Ward: J.7, 1.9, 1.10, 1.13, 1.14, 2.9, 3.1, 3.3, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 5.1, 5.15, 6.3, 6.4, 6.10, 6.13, 6.15, 7.3, 7.8, 7.15a, 7.16, 8.2, 8.3, 8.6; 1.2 (after Hélldobler and

Wilson); 1.3 (after Wilson); 1.11 (after Eberhard); 2.6 (after Bristowe); 5.30 (after M. F. Land); 7.10 (after Brusca and Brusca); 7.11 (after Collins Guide to Insects); 7.17 (after Brusca and Brusca);

10.6 (after Heijn from Ulenberg). Computer-generated images by the author: 1.14, 1.15, 1.16, 5.3%, 5.5*, 5.6%, 5.7%, 5.9%, 5.10%,

5.11%, 5.12, 5.20", 5.28, 6.2", 6.3%, 6.5, 6.6, 6.8, 6.11, 6.12, 6.14, 7.1, 7.9, 7.12, 7.13, 7.14 (images marked with an asterisk redrawn by Nigel Andrews); by Jeremy Hopes 5.13. Heather Angel: 1.5, I.11b, 5.21, 8.1. Ardea: 1.8 (Hans D. Dossenbach), I.11a (Tony Beamish), 6.7 (P. Morris), 9.3e (Bob Gibbons). Euan N. K. Clarkson: 5.28. Bruce Coleman: 10.3a (Gerald Cubitt), W. D, Hamilton: Carmichael Jr). Chris

10.1,

O”Toole:

10.2,

10.4,

10.5,

10.7. Ole Munk:

I.6a and b. Oxford Scientific Films:

5.31. NHPA: 1.4 (Rudie

6.1 (James Kuiter), 2.1

(Densey Clyne), 5.19 (Michael Leach), 5.19b (J. A. L. Cooke), 10.2b (K. Jell), 10.3b (David Cayless). Portech Mobile Robotics Laboratory, Portsmouth: 9.2. Prema Photos: 8.5 (K. G.

PrestonMafham). David M. Raup: 6.9. Science Photo Library: 9.3a (A. B. Dowsett), 9.36 (John Bavosi), 9.3c (Manfred Kage), 9.3d (David Patterson), 9.6 (J. C. Revy). Dr Fritz Vollrath: 2.2, 2.3, 2.4, 2.10, 2.11, 2.12, 2.13. Zefa: 9.1. 1.1 from Michell, J. (1978) Simulacra. London: Thames and Hudson.

2.5 from Hansell (1984). 2.7 and 2.8 from Robinson (1991). 2.14 and 2.15 from Terzopoulos et al. (1995) © of Technology.

1995 by the Massachusetts Institute

3.2 courtesy of the Hamilton Spectator, Canada. 4.1 courtesy of J.T. Bonner 1965, © Princeton University Press.

PICTURE

ACKNOWLEDGEMENTS

5.2 from Dawkins (1986) (drawing by Bridget Peace), 54a, b and d, 5.8a-e, 5.24a and b from Land (1980) (redrawn from Hesse, 1899).

5.4c from Salvini-Plawen and Mayr (1977) (after Hesse, 1899). 5.16a and b Hesse from Untersuchungen,ber die organe der Lichtempfindung bei niederen thieren, Zeitschrift fur Wissenschaftliche Zoologie, 1899. 5.17, 5.19d and e, 5.25, 5.26 courtesy of M. F. Land. 5.18a and f, 5.27, 5.30 drawings by Nigel Andrews. 5.22

drawing

by Kuno

Kirschfeld,

reproduced

by

permission

of

Naturwissenschaftliche

Rundschau, Stuttgart. 5.23 courtesy of Dan E. Nilsson from Stavenga and Hardie (eds.) (1989). 5.29a-e courtesy of Walter J. Gehring et al., from Georg Halder et al. (1995). 6.16 from Meinhardt (1995). 7.2, 7.4, 7.5, 7.6, 7.7 from Ernst Haeckel (1904) Kunstformen der Natur. Leipzig and Vienna: Verlag

des Bibliographischen Instituts. 7.15b from Raff and Kaufman (1983) (afterY. Tanaka, ‘Genetics of the Silkworm’, in Advances in Genetics 5: 239-317,

1953),

8.4 from Wilson (1971) (from Wheeler, 1910, after F. Dahl). 9.4 Jean Dawkins. 9.5 © K. Eric Drexler, Chris Peterson and Gayle Pergamit, All rights reserved. Reprinted with per-

mission from Unbounding the Future: The Nanotechnology Revolution. William Morrow, 1991.

CLIMBING

MOUNT

IMPROBABLE

C

H

A

P

T

ER

I

FACING MOUNT RUSHMORE a

A

Tl HAVE

JUST

\

LISTENED

TO

A

LECTURESIN

WHICH

THE

topic for discussion was the fig. Not a botanical lecture, a literary one. We got the fig in literature, the fig as metaphor, changing perceptions of the fig, the fig as emblem of pudenda and the fig leaf as modest concealer of them, ‘fig’ as an insult, the social construction of the fig, D, H. Lawrence on how to eat a fig in society, ‘reading fig’

and, I rather think, ‘the fig as text’. The speaker's final pensée was the following. He recalled to us the Genesis story of Eve tempting Adam to eat of the fruit of the tree of knowledge. Genesis doesn't specify, he reminded us, which fruit it was. Traditionally, people take it to be an apple. The lecturer suspected that actually it was a fig, and with this piquant little shaft he ended his talk. This kind of thing is the stock-in-trade of a certain kind of literary mind, but it provokes me to literal-mindedness. The speaker obviously knew that there never was a Garden of Eden, never a tree of

knowledge of good and evil. So what was he actually trying to say? I suppose he had a vague feeling that ‘somehow’, ‘if you will’, ‘at some level’, ‘in some sense’, ‘if I may put it this way’ it is somehow ‘right’

that the fruit in the story ‘should’ have been a fig. But enough of this. It is not that we should be literalist and Gradgrindian, but our elegant

lecturer was missing so much. There is genuine paradox and real poetry lurking in the fig, with subtleties to exercise an inquiring mind and

CLIMBING

MOUNT

IMPROBABLE

wonders to uplift an aesthetic one. In this book I want to move to a position where I can tell the true story of the fig. But the fig story is only one out of millions that all have the same Darwinian grammar and logic—albeit the fig story is among the most satisfyingly intricate in evolution, To anticipate the central metaphor of the book, the fig tree stands atop one of the highest peaks on the massif of Mount

Improbable. But peaks as high as the fig’s are best conquered at the end of the expedition. Before that there is much that needs to be said,

a whole vision of life that needs to be developed and explained, puzzles that must be solved and paradoxes that must be disarmed. As I said, the story of the fig is, at the deepest level, the same story as for every other living creature on this planet. Though they differ in surface detail, all are variations on the theme of DNA and the 30 million ways by which it propagates itself On our route we shall have occasion to look at spider webs—at the bewildering, though uncon-

scious, ingenuity with which they are made and how they work. We shall reconstruct the slow, gradual evolution of wings and of elephant trunks. We shall see that ‘the’ eye, legendarily difficult though its evolution sometimes seems, has actually evolved at least forty and prob-

ably sixty times independently all around the animal kingdom. We shall program computers to assist our imagination in moving easily through a gigantic museum of all the countless creatures that have ever lived and died, and their even more numerous imaginary cousins,

who have never been born. We shall wander the paths of Mount Improbable, admiring its vertical precipices from afar, but always restlessly seeking the gently graded slopes on the other side. The meaning

of the parable of Mount Improbable will be made clear, and much else besides. I need to begin by clarifying the problem of apparent design in nature, its relationship to true, human design and its relation-

ship to chance. This is the purpose of Chapter I. The Natural History Museum in London has a quirky collection of stones that chance to resemble familiar objects: a boot, a hand, a baby’s skull, a duck, a fish. They were sent in by people who genuinely suspected that the resemblance might mean something, But ordinary stones weather into such a welter of shapes, it is not surprising if oc-

casionally we find one that calls to mind a boot, or a duck. Out of all 4

FACING

MOUNT

RUSHMORE

the stones that people notice as they walk about, the museum has preserved the ones that they pick up and keep as curiosities. Thousands of stones remain uncollected because they are just stones. The coincidences of resemblance in this museum collection are meaningless, though amusing. The same is true when we think we see faces, or animal shapes, in clouds or cliff profiles. The resemblances are accidents. The craggy hillside in Figure I.I is supposed to suggest the profile of the late President Kennedy.

Once you have been told, you

can just see a slight resemblance to either John or Robert Kennedy. But some don't see it and it is certainly easy to believe that the resemblance is accidental. You couldn't, on the other hand, persuade a reasonable person that Mount Rushmore, in South Dakota, had just happened to weather into the features of Presidents Washington,

Jefferson, Lincoln and Theodore Roosevelt. We do not need to be told

that these

were

deliberately

carved

(under

the

direction

of

Gutzon Borglum). They are obviously not accidental: they have design written all over them.

.

—_

—

oi

ve =.