Current Vol 19 No 3 R96

rapidly supplant their ancestors. The notion that is driven by the (Re)Reading The ‘Kluge-Kerfoot hypothesis’, published self-organization of molecules. Some Origin in 1973, proposes that the traits most of these ideas are worthwhile, others variable within populations are those simply silly; but none does more than most likely to differ markedly between add a room or two to the Darwinian ’s 1859 book On the populations. This idea, now the manse. Often declared dead, Origin of Species is much referenced, foundation for sequence-based tests still refuses to lie down. So by all means especially in this double anniversary of natural selection on genes, appears let’s retain the term. It is less of a year. But, does anyone still read it? in chapter five ofThe Origin. Darwin jawbreaker than ‘modern evolutionary And, if so, what is the book itself like even suggests that family selection biology’, and has not, as was feared, as a text? We have asked might explain the evolution of sterile misled people into thinking that our field from a range of fields— evolutionary insect castes. has remained static since 1859. What biologists, but also geneticists, No popular work of science — and better honorific than ‘Darwinism’ to fête ecologists, paleontologists and we must remember that this book the greatest in history? molecular biologists — to re-read (or was written mainly for the public, not read) The Origin for Current Biology. Darwin’s colleagues — ever had such Jerry A. Coyne is an evolutionary geneticist Below are the responses, contributed a dramatic impact on both scientific in the Department of and Evolution by: Andrew Berry, Matthew Cobb, opinion and human consciousness. at the . He works on Simon Conway Morris, Jerry Coyne, Buttressed by innumerable facts the origin of species, using Drosophila as Hopi Hoekstra, Peter Lawrence, Robert gleaned personally or through tireless a model organism, and is the author of the forthcoming book Why Evolution is True. May, Christiane Nüsslein-Volhard, Mark correspondence, Darwin works his Ptashne, Matt Ridley and Marlene Zuk. magic with a subtle but irresistible style of argument. He asks rhetorical Robert May questions, disputes with himself, Jerry Coyne raises and answers every objection On being invited to re-read Darwin’s to his own theories, and in the end Origin of Species and comment on it, Many of my colleagues say that so convinced his readers that they my first question was which edition. we should quietly shelve the term not only bought his ideas, but in the As Darwin sought to mollify critics, ‘Darwinism’. We don’t, they argue, process jettisoned three thousand successive editions lengthened, call classical physics ‘Newtonism’, years of religious explanation for life until the sixth and final edition is nor relativity ‘Einsteinism’. So why and its apparent design. twice the length of the first. Some of saddle our field with an eponymous And, from the outset, Darwin got these changes are adumbration of personality cult, especially when it mostly right. Evolution occurred, examples to strengthen an argument, we’ve learned so much since The all species have common ancestors, others are circumlocutions to avoid Origin of Species appeared in 1859? and the main (but not the only) engine problems (for example, given that Why not call it ‘modern evolutionary of evolutionary change is natural the nuclear forces which fuel the biology’, or the insidious-sounding selection. These ideas have endured sun were unknown to the physics ‘neo-Darwinism’? The best answer to unchanged, becoming scientific truths. of Darwin’s day, Kelvin and others this revisionism is to re-read The Origin Over the past century and a half, much observed that the geological time itself. In no other field has the work of of our time has been spent sweeping available for evolutionary processes a single individual created a research up after the Darwinian elephant, was at most a few million years; this is program that has endured for a century analyzing the droppings from The why, in successive editions, numerical and a half. (It is inconceivable, for Origin. True, Darwin wasn’t always estimates of the sweep of evolutionary example, that a modern paper on correct: he got genetics wrong, and time disappeared into a verbal fudge). electromagnetism would begin with the his views on species and So I re-read the first edition. words “Ever since Faraday...”) Besides are pretty wonky. And of course A century and a half has passed, but Darwin’s ‘Big Five’ ideas: evolution, evolutionary theory has advanced: the language remains fresh, and the natural selection, common ancestry, systematics, continental drift, and ideas compelling. As John Bonner lineage splitting (speciation), and are all areas and I wrote in introducing a reprinting gradualism, The Origin broaches ideas untouched by his looming shadow. of The Descent of Man in 1981, “It is only now coming to fruition — ideas Still, these advances amount to the genius of Darwin that his ideas, often tossed out in one brief sentence. refinements of Darwinism rather than clothed as they are in unhurried We read, for instance, about how its Kuhnian overthrow. Evolutionary Victorian prose, are almost as modern evolution can be constrained by biology hasn’t suffered the equivalent now as they were when they were first pleiotropy, “the many unknown laws of of quantum mechanics. But some published.” And never before or since correlation of growth”. We encounter biologists, chafing in their Darwinian has a book so changed our view of the the idea that some traits might not straitjacket, periodically announce world, and of our place in it. be subject to any form of selection, new world views that, they claim, will This being acknowledged, I doubt and that these neutral traits could overturn our view of evolution, or at that The Origin is commonly read remain as polymorphic “fluctuating least force its drastic revision. During today as an inspiration for research. elements”. There is the suggestion that my career, I have heard this said about But it is heavily cited: a recent punctuated patterns in the fossil record punctuated equilibrium, molecular analysis of books in ecology and could be caused by rapid evolution drive, the idea of symbiosis as an evolution puts it a close second to in small peripheral populations that evolutionary force, evo-devo, and the Fisher’s Genetical Theory of Natural Magazine R97

Selection, and well ahead of most contemporary monographs (Elworthy (2007). Bull. Brit. Ecol. Soc. 38, 55-57). I suspect, however, that this may owe more to the Darwin industry among historians and philosophers of science than to basic researchers. Ultimately, however, The Origin provides a telling illustration of the inadequacy of measuring true impact by counting citations. Interestingly, Wallace’s books — including that which gave us the classification of biogeographical realms which we still use — do not feature in Elworthy’s catalogue. Even in their own day, there was something of cricket’s distinction (which persisted for a further century) between Gentlemen and Players in their relationship. It should, however, be acknowledged that Victorians often referred to the Darwin–Wallace idea of evolution by natural selection. All of which emphasises the disparity between the high-profile Darwin bicentennial celebrations and associated academic industry, and the relative neglect of Wallace. In the interests of equal time, I am now off to re-read Wallace.

Robert, Lord May of Oxford, OM AC FRS, is a physicist-turned-ecologist and Professor in the Zoology Department at Oxford University. He was Chief Scientific Adviser to the UK Government (1995–2000) and President of the Royal Society (2000–2005).

Matt Ridley

I deliberately picked up a late edition of The Origin of Species, the sixth edition, published in 1872, interested to see how Charles Darwin, an obsessive reviser of his own prose, had coped with all the comments the book had received in the 13 years since it had first come out. For instance, in this edition, Darwin enthusiastically adopts Herbert Spencer’s coinage ‘survival of the fittest’. The book certainly reads in places like a conversation with his Original Origin: Frontispiece of the first edition 1859. Reproduced with permission from John critics, as in this sardonic passage: “My van Wyhe ed., The Complete Work of Charles Darwin Online (http://darwin-online.org.uk). judgment may not be trustworthy, but after reading with care Mr Mivart’s book, builds his argument for a single great and small. There is no topic on which and comparing each section with what rule by finding hundreds of curious he cannot find a race of pigeon or a I have said on the same head, I never anecdotes, experiments, oddities and species of barnacle, or story from a before felt so strongly convinced of the surprises in the cornucopia of , naturalist somewhere in the world, to general truth of the conclusions here each one seemingly exceptional yet all illustrate his point. Lots of them would arrived at.” pulling towards a general conclusion. not pass muster today, being, to put Biology is the science of exceptions The power of the book comes not it mildly, not from the peer-reviewed to rules, and what is so striking about from its relentless logic so much as its literature: “I may add, that according to The Origin of Species is that Darwin enormous reservoir of examples large Mr. Pierce, there are two varieties of the Current Biology Vol 19 No 3 R98

wolf inhabiting the Catskill Mountains, Peter Lawrence literature, but banned from scientific in the United States, one with a light usage. I don’t know why, but dulling greyhound-like form, which pursues “The greatest scientific advance of down our scientific writing is not in our deer, and other more bulky with shorter the last 1000 years was providing the best interest. By contrast, in Darwin’s legs, which more frequently attacks the evidence to prove that human beings time, Victorian fashion encouraged shepherd’s flock.” are independent agents whose lives a flowery style as well as intellectual When Darwin goes wrong, it is on earth are neither conferred nor freedom; he took full advantage of nearly always because he relies controlled by celestial forces…… both. He could write explorative and on the wrong ideas of others — on nothing was more important than educative prose. He could spend many received wisdom that turned out providing the means to release men pages explaining narrow but important to be incorrect. There are three and women from the hegemony of the distinctions between different striking examples: first, heredity; with supernatural.” (Mellman, I. and Warren, viewpoints and, time and again, splendid, waffling obscurity, Darwin G. (2000). The road taken: past and one can see the outcome of careful attributes variability to “changed future foundations of membrane traffic. reading and deep reflection. Our data- conditions of life”, to “correlated Cell 100, 99–112.) dominated publications, pared down growth” and to the “use or disuse In this vital mission to discredit the to fit them into limited space, would of parts”. He even concedes the supernatural, nothing has proved more be much more comprehensible if there grossest of Lamarckian fallacies: “The important than The Origin of Species. were more argument, more explanation evidence that accidental mutilations Here is just one nice argument from and more justification; indeed, if we can be inherited is at present not hundreds: “He who admits the doctrine reflected more, I think we could make decisive; but the remarkable cases of the creation of each separate big reductions in our published pages observed by Brown-Sequard in species, will have to admit that a by making sure they carry and convey guinea-pigs, of the inherited effects of sufficient number of the best adapted at least one message of note. operations, should make us cautious plants and were not created Although Darwin’s book is primarily in denying this tendency.” for oceanic islands; for man has about arguments and evidence, he Second, the age of the earth; Darwin unintentionally stocked them far more does not forget the power of a simple accepts the calculation of Sir William fully and perfectly than did nature.” experiment. Just one example: he Thompson (later Lord Kelvin) that the argues that the worldwide dispersal earth is about 200 million years old, of some freshwater plants is due to but confesses uneasily that “it can “The power of the book migrating birds carrying mud on their hardly be considered as sufficient for feet; so he takes three tablespoons the development of the varied forms comes not from its relentless of mud from a local pond and, over of life.” Thompson was out by a factor logic so much as its enormous 6 months, found he could grow 537 of seven, because he had omitted the ­reservoir of examples large plants from it. Darwin has whole effect of radioactivity which is slowing chapters discussing the points of view the cooling of the earth. and small.” of others, dismissing contrary opinions Third, continental drift; Darwin (Matt Ridley) with persuasive arguments. He took struggles to explain why different time to communicate extensively continents have different faunas on with other specialists. By contrast, in them, and why the geological record modern scientific discourse, we see is so intermittent in most places. He I had only dipped into this wonderful the deadening hand of a new etiquette thinks that land bobs up and down in book in my student days. But what fuelled by careerist calculations. the same place: “the great oceans are a revelation for a somewhat jaded We now have little open debate, still mainly areas of subsidence, the scientist to read it now! It is not only different views are avoided rather than great archipelagoes are still areas of the brilliance, farsighted and original confronted, controversial papers are oscillations of level, and the continents nature of the ideas, there is the sheer not quoted and their publication is areas of elevation.” diversity of knowledge, the pervading resisted. But, of course, Darwin not The Origin of Species is a fossilized presence of thought, of simple direct only had something important to say, scientific argument. That is to say, it experiments, of debate, of argument, he also did not have to keep in with is a moment of intellectual awakening the consideration of other views opinion-formers in order to get grants! frozen in its own time. It was superbly and the style. In writing and reading adapted to its Victorian environment, scientific articles nowadays, we Peter A. Lawrence has studied the genetics of struggled successfully for existence, become imprisoned, constrained in design using insects for 45 years. He is currently working in the Zoology Department proved fit enough to survive and gave what is considered appropriate and of the and the MRC rise to still fitter living descendants, our vocabulary is reduced. Also our Laboratory of , Cambridge, which survived many attempts to sentences are stifled by fashion and UK. drown them in new-fangled fallacy, by journals that kill invention and having shed along the way their worst independence with their strict word features. limits and their ‘house style’. Just one Matthew Cobb example: punctuation. Darwin used everything, even the long dash and Even the most ardent evolutionist Matt Ridley is the author of, among other books, The Red Queen, and the the exclamation mark. In my scientific regularly shakes his or her head in biography of Francis Crick. He lives near writing I have been frequently told that wonder at an amazing adaptation and Newcastle upon Tyne, UK. these are not allowed — OK for great asks: how on earth did that evolve? Magazine R99

Darwin was no different, as shown In the pages that follow, he by what may seem to be one of the emphasises the existence of stodgier chapters of The Origin of variation for various ‘instincts’, Species — chapter eight on ‘instinct’. and puts forward an explanation This chapter deals with the evolution of how they might have evolved. of behaviour and focuses on the In the case of pointing in hunting astonishing behaviour of social dogs, he points out it is merely “the insects, in particular, honeybees exaggerated pause of an animal and their intricate honeycombs. preparing to spring on its prey”, As Darwin writes: “He must be while the evolution of cell-making a dull man who can examine the in honeybees can be understood in exquisite structure of a comb, so terms of a series of the existence of beautifully adapted to its end, without discrete behavioural elements. Some enthusiastic admiration.” of these putative stages can be seen Darwin was not the first person in various bee species — the wax to think about the evolution of cells produced by bees vary from the behaviour — his grandfather, cylinders produced by bumble bees Erasmus Darwin, as well as the to the elaborate hexagons made by Frenchmen Jean-Baptiste Lamarck honeybees. and Pierre-Jean Cabanis, had all Darwin also describes a series of tackled the subject at the end of the experiments he carried out which 18th century. But Charles Darwin’s showed that the thickness of the approach was doubly different cell wall was a decisive factor in to those of his predecessors. He indicating to the honeybees when Fact: At New York’s LaGuardia airport. Photo- interpreted behaviour as a product to stop work. By adding coloured graph kindly provided by Alex Gann. of evolution by natural selection, wax, he showed that several bees thereby obliging himself to explain will act together on making cells, behavioural adaptations in terms of with one individual moving from one examples from cattle breeding and other, less developed characters. cell to another before it is finished, horticulture to back up his insight, And, as shown by virtually every indicating that bees, like other there is a direct link between page of The Origin, he was incredibly animal architects described in the this explanation and what was rigorous, seeking to address all chapter, do not have an internal probably the greatest development possible objections to his theory, ‘image’ of what they are building. in evolutionary thinking in the last grinding down criticisms one by one. Darwin then argued that natural 50 years — Bill Hamilton’s work on The material in chapter eight was selection would have given an kin selection, ‘inclusive fitness’ and particularly important to Darwin, advantage to those bees that could the evolution of altruism. and not only because it was hard make the most economic use of the However, the most important to imagine how, say, bees might precious wax, thereby encouraging contribution of this part of Darwin’s have evolved the ability to make the appearance of hexagonal cells. book is its unstated implication that hexagonal cells. He recognised that But the most important part of the human mind is on a continuum the existence of widespread sterility this chapter centres on what Darwin with those of animals. Just as his in social insects — dealt with in some called the “special difficulty” of study of morphological evolution detail in this chapter — presented sterility in social insects: “With showed us that we are nothing him with “one special difficulty, which the working ant we have an insect special — just a particularly smart at first appeared to me insuperable, differing greatly from its parents, yet and talkative bipedal ape — his and actually fatal to the whole theory absolutely sterile; so that it could work on ‘instinct’ implies that human [of natural selection]”. His resolution never have transmitted successively mental life can be understood of this fundamental problem not only acquired modifications of structure or as the product of evolution and, showed his genius, it also prefigured instinct to its progeny. It may well be above all, that consciousness is a some of the most important asked how is it possible to reconcile physical phenomenon. Darwin not developments in evolutionary theory this case with the theory of natural only gave us the means to interpret over a century later. selection?” the whole of the natural world, he Darwin starts his chapter on Darwin’s explanation of the also provided us with the tools instinct by linking behavioural and selection of sterile individuals is that needed to investigate one of the morphological adaptations: “No “selection may be applied to the greatest scientific and philosophical complex instinct can possibly be family, as well as to the individual, conundrums: where our thoughts produced through natural selection, and may thus gain the desired end.” come from. except by the slow and gradual In other words, if individuals that are accumulation of numerous slight, related to the sterile ants reproduce, Matthew Cobb is a Senior Lecturer in yet profitable, variations”, he writes, and somehow share the character in Animal Behaviour at the University of Manchester. He is the author of The Egg emphasising that these variations question, then natural selection can & Sperm Race: The Seventeenth Century are “produced by the same unknown lead to the evolution of sterility. Scientists who Unravelled the Secrets of causes which produce slight Although Darwin was referring Sex, Life and Growth (published in the USA deviations of bodily structure”. to ‘family selection’, and used as Generation). Current Biology Vol 19 No 3 R100

Christiane Nüsslein-Volhard and Darwin had a much more direct Embryonic as well as larval traits approach and closer contact to nature had been most important in defining “When we no longer look at an than is possible nowadays. Of course, larger groups in the natural system. organic being as a savage looks at a he was singularly fortunate, because Darwin explains this pattern by the use ship...” — the first thing that struck me the long voyage on the Beagle allowed and disuse of organs: as there is no when re-reading The Origin: Darwin’s him as a naïve observer — unprejudiced selection acting on embryonic forms book is wonderful literature — exciting, and with a mind wide open — to collect that are not yet functional, embryos interesting, very well written, in an and learn about a richness of facts that or larvae will reveal the ‘prototype’ almost colloquial style. Darwin goes is exceptional. However, it would be of a given group, while the adults are to great lengths not to be too tedious entirely wrong to say that his theory often highly specialised and adapted and seems to be constantly worried depended solely on the opportunities to their lifestyle. The barnacles Darwin about losing the reader. To anyone given to him by the voyage. studied, for example, can be recognised interested in biology, the book can as crustaceans only by virtue of their never appear dull: there are so many larval form. Likewise, he explains the facts and observations about natural “I had only dipped into this existence of rudimentary organs that history, the diversity of animals and would have no reason to exist were it a plants — after all, this is the topic of wonderful book in my student creator’s world. Although this evidence the book — but also about agriculture, days. But what a revelation for for his theory is often overlooked, and domestic crops or the breeding of a somewhat jaded scientist to developmental biology until recently pigeons, and spreading out into played little if any role in post-Darwinian behaviour, geology, fossils, . read it now!” evolutionary theories, the mere fact All of these observations are placed in (Peter Lawrence) that a natural classification is possible the context of the “one large argument” at all is most compelling, and one of descent with modification. There is wonders why others before Darwin hardly any field that is left out — except have not interpreted common traits for, perhaps, chemistry and physiology. In the final chapter ofThe Origin, by assuming common ancestors. Darwin did not know about which impresses me most, the It is striking that the famous single microorganisms, and therefore his book argumentation is based largely on illustration of the book is used to deals little with pathogen resistance well-known work of other naturalists, as explain this argument, underlining the or health, a topic which nowadays is well as his own thorough investigations importance Darwin himself attributed recognized as most important for the of barnacles. The chapter deals with to it. In this illustration, Darwin fills in evolution of organisms. In retrospect, classification: “From the first dawn the missing intermediates by designing Darwin’s biggest limitation — as many of life, all organic beings are found to a hypothetical pedigree to explain the have pointed out — was that he did resemble each other in descending natural system: if all the species that not understand genetics; this worried degrees, so that they can be classed had ever existed would come to life him a great deal, and he tried hard to in groups under groups.” People again, the missing intermediates — delineate “laws of variation”, but he have ordered plants and animals long together with all those that died out in could not explain the origin of variation. before, most notably according to side branches — would also appear, He emphasizes, however, that sexual Linnaeus’ systema naturae (1735), a allowing an undisputable natural reproduction increases variation and ‘natural’ system, which takes affinities classification, based on common fitness, and acknowledges the “strong or relationships between organisms into descent with modification. principle of inheritance”. Reading account as opposed to an ‘artificial’ When settled at Downe, having the these chapters, it sometimes feels classification based on, say, size, advantage of living on the family purse, as if Darwin got close to Mendel’s colour, habitats or type of food. It had without the need for grant writing, job laws, but all was buried in a big mess been realised that different traits are finding and scientific administration, of often contradictory reports about of different value for classification, Darwin could follow up his thoughts all sorts of crosses among wild and and that similarities could also arise and obsessions with utmost freedom, domesticated species. Perhaps, in the in parallel: the different value of interrupted only by his family and case of inheritance, the abundance of homologous (similar by common type) illness. We owe his great book also observations and cases that make The as opposed to analogous (similar by to a loving wife, his kids, pigeons Origin so entertaining to read, clouded common function) structures was and plants, and a walk around the Darwin’s view and made it impossible clearly appreciated. Darwin emphasises sandwalk everyday. I don’t envy him for for him to see the clear rules that that his theory of descent with the illness or for his fame, but for his Mendel recognized through his elegant modification has the power to explain independence and for the peace of the experimental system. the natural system, and he mentions the place which provided the setting for The Origin is also a testimony of intuition of the biologists before him: the development of the great theory of Darwin’s obsession — a brilliant idea, “Community of descent is the hidden evolution. conceived rather early and his fear he bond naturalists were unconsciously might be hanged for it, as well as an seeking” in their classifications. Christiane Nüsslein-Volhard is a director at urge to be understood, to find support. The fact that in embryos the more the Max Planck-Institute for Developmental Biology in Tübingen, Germany, where A book like this could probably not be general features that characterise a type she studies the genetic basis of embryo written by a present-day scientist: for develop earlier than the specialised development in fish and flies. She won with one, much of the diversity of nature ones had also been observed before, Ed Lewis and Eric Wieschaus the 1995 Nobel has disappeared in the meantime, in particular by Karl Ernst von Baer. Prize in Physiology or Medicine. Magazine R101

Mark Ptashne

In the last chapter of the first edition of The Origin of Species Darwin famously says “...this whole volume is one long argument…”, and urges the reader to weigh all the pros and cons. Sly fellow, as though all scientific positions, ‘proofs’, are not arguments that aim to convince the reader. What is so unusual about The Origin, and what makes it so thrilling, is the abstraction involved here. We are urged to accept the idea that species arose by natural selection in the face of an incoherent picture of how variation arises and is transmitted, and the then- unimpeachable testimony of the physicists that the earth cannot be as old as required. Darwin rarely left his house, motivated, I would guess, by his dread of facing attacks he knew were irrelevant or wrong, but which he couldn’t answer. I say ‘encountering’ The Origin, rather than ‘re-encountering’, because my previous attempts to read the book failed. Who has the patience to dig through the convoluted sentences, extracting the buried nuggets? Other writings of Darwin are delightful, and maybe this dangerous book was written so as, once again, to deflect confrontation. In any event my Kindle came to the rescue — there I found a ‘condensed’ version of The Origin of The Origin: The first pencil sketch (1842). Reproduced with permission from John van Origin in which each sentence has Wyhe ed., The Complete Work of Charles Darwin Online (http://darwin-online.org.uk/). been pared down by the elimination of unnecessary words. And in this version the book comes to life. taking, i.e. an easily understood set animals. In hindsight The Origin Had I stuck to the original I might of interactions that required more illustrates a principle of scientific have gotten the ‘big picture’, but I looking than thinking. Thank heaven analysis: if you want to uncover would have skimmed the details, the (sic) that is not true, for how dull universal mechanisms, concentrate astounding array of observations our tasks would have been (and on the simplest examples; because, brought to bear. Here’s one with an continue to be). The good Bishop, paradoxical as it might seem at first, implied prediction: “the absence of stumbling across the lambda Darwin was analyzing the ‘simplest’ distinctive breeds of cat […] may be switch in its current guise, would examples of evolution. Unlike what attributed to selection not having surely remark on the impossibility happened during the evolution been brought into play.” I suspect of evolving this intricate, seemingly of bacteria, essentially no new that Rocky, my Abyssinian, would irreducibly complex machine. We enzymatic activities appear in the reject the idea that humans have would have him over a barrel: we can elaboration of plants and animals. since moulded his type rather than explain how a set of simple binding In fact, we are made up of a number the other way around. reactions, each additional binding of genes embarrassingly close to Darwin jolts us into confronting reaction making the machine work a those found in a fly, and the fly genes an inspiring fact: the world is not bit more efficiently, went into making encode proteins very similar to those transparent. Every interesting the switch the marvellous thing it found in us. scientific construct is a product appears to be. The trick natural selection of the imagination. I was recently Darwin of course knew nothing exploited, so as to use common assured that the lambda switch — about lambda — in fact, The Origin, enzymes to produce disparate the molecular mechanism controlling in its first edition, considers only organs and organisms, was to vary lysogeny versus lysis of the lambda ‘recent’ evolution, that which resulted the regulation of these common bacteriophage — was there for the in the diversification of plants and enzymes. Many of these enzymes Current Biology Vol 19 No 3 R102

have a wide array of possible cannot predict where these changes purpose of piling up the evidence. substrates, and what changes will be found and, once found, Darwin knew his enemy intimately, during evolution are the specificities these changes may be hard to but was far too astute to engage in a imposed by binding reactions. The interpret. Surely that is a big part of head-on clash. Blind Plumber will work on any pipe the problem in analyzing the multi- Darwin was right, and he knew it. in your house — you have to lead, or factorial contributions to human His expressions of doubt are largely ‘recruit’, him to the one or more pipes variation and disease. Darwin never rhetorical and how seamless — at that should be worked on. Similarly, said it would be easy. Indeed his least from a distance — is the the enzyme RNA polymerase will vision predicts it can’t be. edifice upon which he constructs transcribe into RNA essentially any his theory. Yet, it is equally intriguing gene to which it is recruited. This Mark Ptashne is Ludwig Professor of how he conceals his intellect: trick applies to every aspect of the Molecular Biology at Sloan Kettering the carefully marshalled facts are Institute in New York, where he studies regulated production of proteins and mechanisms of gene regulation. He has allowed to speak for themselves other macromolecules — including authored two books (A Genetic Switch and the implications introduced with transcription of genes, splicing, (Third Edition) and Genes and Signals, restraint and circumspection— a transport and translation of mRNA, with Alex Gann) and occasionally writes for sotto voce naturalist. Darwin never proteolysis of proteins, transduction Current Biology about biological regulation doubted his abilities. The Origin, of extracellular signals, and so on. and related topics. however, offers precious few clues Over recent evolutionary timescales as to the roots of his intellectual it is the recruiters and their sites on adventure. Cambridge, where his targets — genes, proteins, RNA — “...my previous attempts to scientific mind actually crystallized, that changed, not the enzymes read the book failed. Who has goes unmentioned. In the opening themselves. And that, it would seem, line of The Origin, Darwin hints at is an easy task for natural selection. It the patience to dig through the Beagle being the catalyst, but is not surprising that we understand the convoluted sentences, what a contrast this book is to what less well how the earlier stages ­extracting the buried nuggets?” we usually refer to as The Voyage. In evolved. (Mark Ptashne) this earlier work plenty of questions A regulatory world that uses are posed, but very few answered. binding reactions to impose True the Malthusian formula is specificity inevitably looks messy, invoked, but the sense of enquiry is you might say unnecessarily far more one of muddle. The seeds ‘complex’. To get these rather crude Simon Conway Morris were sown, but germination was a reactions to work properly requires slow process and in many ways The add-on after add-on, usually in A small confession: No! No! Not that Origin is a late flower. Yet it reveals the form of more binding reactions one! I confess, yes, this is the first glimpses of an intense acuity of that inhibit one or the other step, time I have read The Origin cover to vision. Combine this with an that result in destruction of a cover. And could it be that, as with enviable gift of lateral thinking and, protein when it exceeds a certain another well-known sphere of human if the dark brain of Darwin is not concentration, that inhibit another engagement, a little experience, exposed, it is at least visible. crucial binding reaction, and so on. dare I say maturity, helps? A book Such is also clear because even These ever-tinkered-with systems of genius? Of course! But what though The Origin is a deep work, but at a price: just as the suddenly became clear is that this book, its surface sparkles with regulatory world can be assembled is a book haunted by the ghost of prescient insights. Of course, a stepwise, so is it rather easily William Paley — the grandfather of priori readings from our vantage disassembled, with each subtraction creationist thinking and exponent point can make too much of half- making the situation worse. Glance of seemingly irrefutable arguments articulated thoughts, but in this through a modern cancer textbook for organic design. The Origin is mind of a genius we see a catalogue and you will see a kind of ‘evolution Darwin’s riposte. Its metaphorical of potentialities. These include in reverse’ — the accumulation of power depends on suspense and a hypotheses that we now identify mutations that take the cell back scattering of clues, but significantly with r-selection, , to a more ‘primitive’ state, one Paley himself is mentioned only once. the red queen, incumbency, devoid of the usual controls. Almost And cleverly not in the context of his biogeographical barriers, character without exception, every mutation ideas on organic design but in an states, stratigraphic hiatuses and involves, directly or indirectly, a oblique dig at the question of natural embryological recapitulation. So, binding reaction, or the creation or evil. First and foremost, The Origin is too — in a way that still seems destruction of a binding site by an an exorcism of the doctrine of special to puzzle half the biologists I enzyme. creation, and conducted by one of know — Darwin succinctly explains The good news — Darwin would the most skilled exorcists science how ancestors are themselves not have loved it — is that it is easy to has ever seen. The brief crescendo the direct intermediates, and, as see in principle how changes in just in the last chapter is preceded by we know now, may bear precious a few surface residues of a protein repeated and sudden flashes of little resemblance to their distant can, by affecting binding reactions, disdain, a quick insertion of the knife progeny. But even when his genius contribute to recent evolutionary before the narrative calmly continues fails him there is still a whiff of future change. The bad news is that one in its ostensibly more objective discoveries. Magazine R103

But there is something obsessive about Darwin. Just as he piled up the evidence, so his whole view of evolution was ultimately relentless, an unceasing, almost manic conviction that no piece of evidence was too trivial, too unimportant. Where time is effectively endless, the scrutiny of selection unsleeping and untiring, the most trivial advantage seized upon so The Origin becomes effectively the calculus of biology, where fathomless aeons of geological time witness evolution creeping along gradualistic paths. No wonder his eliding of variety with species and agonizing over the nature of hybrids and the question of sterility is so central to his argument of continuum and why, so rightly, he was deeply puzzled by what we now refer to as the Cambrian ‘explosion’. Yet for all of that, the Origin has some strange lacuna. Despite Darwin’s enthusiasm for the perfection of form and the Back to the roots: Darwin’s sandwalk and ‘thinking path’ near Down House in Kent. Photo- graph from wikipedia.org. integration of the organism, the book contains remarkably little on functional biology. He knew the weakest die”, but all to the the book as a work that everyone some medicine, was a skilled greater good as in panglossian cites, but few people have actually dissector, and it is all the odder mode he also wrote “no fear is felt, read. So is Darwin’s masterpiece still because — even if he lived in that death is generally prompt, and valuable 150 years later? Or is our tranquil Down House — England that the vigorous, the healthy and requirement just a form of intellectual hummed with the sound of machines the happy survive and multiply”. hazing, making the newcomers suffer and technological innovation. Is it Like many others after him, Darwin as a rite of passage? I am always a gentleman’s aversion to a sordid muffed the profound problem of struck by Darwin’s ability to use reality? I don’t think so. Again, natural evil. Despite his generosity of details of natural history without being the ghost of Paley and his siren nature when he came to any sort of transfixed by them or viewing them voice of organic design must be metaphysics, again like some of his as an end in themselves. Amidst the expelled. Only later, with The Origin most fervent supporters today, he carefully compiled notes from entrenched, did Darwin reveal his was hopelessly out of his depth. But Mr. Chauncey Wright or the Rev. W.B. deep knowledge of contrivance, at least he knew some of his limits. Clarke, one never loses sight of why as in the form of climbing plants. It is no accident that even as he Darwin is mentioning an example. And if The Origin is an exorcism supposed, absolutely correctly, that The antennae of the Hymenoptera, against Paley, so obliquely Darwin famously “Light will be thrown on for example, “as Westwood has arrives with a mouthful of nails to the origin of man and his history”, he remarked, are most constant in finally hammer shut the coffin of suspected that mind and the origin structure; in another division they differ . Why else the strenuous of life might forever fall outside his much, and the differences are of quite and repeated insistence that the theory. And, as in so many other subordinate value in classification; physical environment can effectively ways, Darwin might just be right. yet no one will say that the antennae play no role in his theory? After in these two divisions of the same all, if biological form should be so Simon Conway Morris is Professor of order are of unequal physiological moulded then might not organisms Evolutionary Palaeobiology in the Earth importance” (chapter 14). The actual Sciences Department at Cambridge, and simply be responding to the ebb and is working on his next book, Darwin’s nature of hymenopteran antennae is of flow of inanimate forces? Compass. little interest to me, but it is abundantly Darwin knew he stood on a clear that we are reading about them Darien peak with almost unlimited in such detail because Darwin was vistas, but was seemingly unaware Marlene Zuk wrestling with the question of how we that he was also staring into an choose characters for classification abyss. Integral to his scheme were Although the students in our graduate of organisms, which remains an metaphors of struggle, the weak and program in take a important question to this day. Few dominant, victory and extinction, core course in evolutionary theory for modern biologists can both appreciate battle and yielding, invasion and which The Origin of Species is required natural history and recognize that it is retreat: “let the strongest live and reading, one could certainly describe not an end in itself. Current Biology Vol 19 No 3 R104

As a behavioral ecologist, I it for the first time. As part of our mid- frequently and so unexpectedly. But, appreciate Darwin’s grappling with level course on evolution at Harvard, curiously, our students seldom have behaviour as a trait, and his trying we assign The Origin (alongside a such a balanced response: they either to understand, in chapter eight, selection of recent/classic papers and love it or hate it. Our statistical analysis whether behaviour is subject to textbook readings) to be read chapter of these data hasn’t gone beyond mere natural selection in the same manner by chapter throughout the semester. eyeballing, but there seems to be no as morphology. Behavior presented This exercise is mildly controversial; major disciplinary effect: life-science Darwin with one of his greatest colleagues have criticized us, saying majors are as likely to love (or hate) challenges, altruism, and it is clear that that we should focus on current The Origin as physicists or historians Darwin saw the study of behaviour as science rather than revisiting the past. or engineers. Here are a few quotations a legitimate avenue for evolutionary Our response is twofold: uniquely from a recent set of anonymous biology. In contrast, modern scientists among the sciences, evolutionary evaluations: spend far too much time splitting biology is dominated by the one disciplinary hairs, distinguishing authority, the one book. If Steve Gould “Textbook unnecessary. Darwin’s ecology from evolution from behaviour, hadn’t entitled his first collection of ‘Origin of Species’ a great reason to and often disparaging whatever essays Ever Since Darwin, we would take course. Journal articles useless.” subfield with which they do not identify. still be starting our papers with these “The Origin = Very Painful” The title of the book is misleading, very words. Second, the continued “I enjoyed reading Darwin’s Origin. It at least in its usual usage as simply relevance and freshness of The Origin seemed appropriate to read the primary The Origin of Species without the is especially remarkable when you source, even if not every idea has found continuation by Means of Natural consider what Darwin didn’t know. still to be correct”. Selection or The Preservation of “The reading of Darwin was Favoured Races in the Struggle for pathetically useless. It did nothing Life. How species begin and how one to add to the course and just made group splits up into two is only a small “The Origin is an exorcism of discussion groups worthless as well.” part of the focus of the book, and even the doctrine of special creation, “Origin — Awesome! So cool to the subtitle doesn’t do it justice. The and conducted by one of the read!” book is about how, when, and why “It’s OK when he’s not talking about organisms can change through time, a most skilled exorcists” plants and pollen, like that time with breathtaking scope that is nonetheless (Simon Conway Morris) the slave-making ants (that was pretty thoroughly plumbed. The Descent of cool).” Man is similarly unfortunately titled “Origin is awful (sorry). Way too long and therefore also perhaps not read and redundant.” as much as it should be and, although Natural selection is an explicitly “Reading the last chapter of The its subtitle, And Selection in Relation genetic theory, and yet Darwin had no Origin over the last week was magical.” to Sex, is more descriptive of the viable theory of transmission genetics; “Reading Darwin is a nice contents, it too is not particularly biogeographic arguments play an requirement, but I don’t think it should compelling. The Descent of Man is important role for Darwin and yet be tested on the exam.” about sexual differences writ large, in he had no knowledge of continental humans as well as other organisms, drift; and speciation, arguably the We would, of course, like to another blockbuster. Who knows – if linchpin of the evolutionary process, transform the “Origin = Very Painful” Darwin had better titles, maybe he was terra incognita for Darwin. crowd into the “Origin — Awesome” would have been even more influential. That Darwin’s “one long argument” one, but we suspect that this will Although it’s hard to imagine how he remains compelling and coherent remain a case of not being able to could have sexed up his last work, The today is testimony to his unwillingness please all the people all of the time. Formation of Vegetable Mould through — except on rare occasion, such as in Regardless, we are confident that, the Action of Worms with Observations the case of bears evolving into whales ten years on — as they go about on their Habits. — to go beyond the data before him. their work in hospitals, at biotech For example, as an acute observer, companies, and perhaps occasionally Marlene Zuk is a Professor of Biology at he was familiar with the extent of at universities — even the students the University of California, Riverside. Her phenotypic, and therefore genetic, who were not enamoured with The research interests center on behavioural ecology and sexual selection, and she variation in natural populations and Origin when they took our course will is particularly interested in the effects of was content to treat genetics as recall with pride that they read every parasites on host behaviour, ecology, and a black box; only later, when his word of the book and grappled with evolution. hand was forced, did he produce even its more obscure and unquoted a specious model of genetics, passages. The details of what we pangenesis. The Origin is thus a book- taught them will be long gone, but Andrew Berry and Hopi Hoekstra length testament to the scientific The Origin and all of its lessons will method. remain. Instead of actually re-reading and We expected the students to respond commenting on Darwin’s Origin in the same way as we did when we first Andrew Berry is a Lecturer in Biology and ourselves, like the other contributors read it – to groan at the occasionally Hopi Hoekstra is a John L. Loeb Associate of this series, we report here on what lumbering Victorian prose, but to Professor of Biology and the Curator of our students had to say about reading appreciate the insights that crop up so Mammals. Both work at .