Downloaded from rstb.royalsocietypublishing.org on October 31, 2010 Evolution: like any other science it is predictable Simon Conway Morris Phil. Trans. R. Soc. B 2010 365, 133-145 doi: 10.1098/rstb.2009.0154 References This article cites 129 articles, 51 of which can be accessed free http://rstb.royalsocietypublishing.org/content/365/1537/133.full.html#ref-list-1 This article is free to access Rapid response Respond to this article http://rstb.royalsocietypublishing.org/letters/submit/royptb;365/1537/133 Subject collections Articles on similar topics can be found in the following collections evolution (2124 articles) Receive free email alerts when new articles cite this article - sign up in the box at the top Email alerting service right-hand corner of the article or click here To subscribe to Phil. Trans. R. Soc. B go to: http://rstb.royalsocietypublishing.org/subscriptions This journal is © 2010 The Royal Society Downloaded from rstb.royalsocietypublishing.org on October 31, 2010 Phil. Trans. R. Soc. B (2010) 365, 133–145 doi:10.1098/rstb.2009.0154 Review Evolution: like any other science it is predictable Simon Conway Morris* Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK Evolutionary biology rejoices in the diversity of life, but this comes at a cost: other than working in the common framework of neo-Darwinian evolution, specialists in, for example, diatoms and mam- mals have little to say to each other. Accordingly, their research tends to track the particularities and peculiarities of a given group and seldom enquires whether there are any wider or deeper sets of explanations. Here, I present evidence in support of the heterodox idea that evolution might look to a general theory that does more than serve as a tautology (‘evolution explains evolution’). Specifi- cally, I argue that far from its myriad of products being fortuitous and accidental, evolution is remarkably predictable. Thus, I urge a move away from the continuing obsession with Darwinian mechanisms, which are entirely uncontroversial. Rather, I emphasize why we should seek expla- nations for ubiquitous evolutionary convergence, as well as the emergence of complex integrated systems. At present, evolutionary theory seems to be akin to nineteenth-century physics, blissfully unaware of the imminent arrival of quantum mechanics and general relativity. Physics had its Newton, biology its Darwin: evolutionary biology now awaits its Einstein. Keywords: evolution; convergence; frogs; theropods; E. coli; viruses 1. INTRODUCTION and so far as the explication (and defence) of the Oxymoronically, the sheer obviousness of organic evol- science of evolution is concerned, it can hardly be ution can only explain the many quotations that assisted by those who ironically treat it as a religion declare the self-evident. Consider, for example, (Midgley 1985). I wonder if paradoxically the diffi- Thomas Henry Huxley’s post-1859 exclamation of culty stems from Darwin himself. Curiously, it is ‘How extremely stupid not to have thought of that!’ seldom appreciated that whatever else his masterpiece (Huxley 1900, vol. 1, p. 170), or more recently per- (Darwin 1860) set out to achieve it was at heart an haps Richard Dawkins’ somewhat hypothetical exorcism of William Paley (Conway Morris 2009). question posed by visiting extraterrestrials as to With consummate skill, and in striking contrast to whether we had yet stumbled on the Darwinian for- the belligerent and graceless rhetoric of some of his mula (Dawkins 1989, p. 1). Both, of course, miss the intellectual descendants, he systematically dismantled point. Whatever Huxley’s talents, he had not the Paley’s creationism. But 150 years on the message remotest chance of formulating a workable hypothesis has evidently failed to sink in. for organic evolution. Indeed, even after the publi- While the aim of this paper is, I hope, straightfor- cation of Darwin’s Origin, he kept on missing the ward, it is also designed to point to some unfinished point (Desmond 1998). So too I suspect any extrater- business. Of course, and as already indicated, the rea- restrial tourists are more likely to enquire whether we lity of evolution is not in dispute. Nor is the Darwinian have yet dropped the habit of killing millions of inno- formulation, for which the evidence is overwhelming. cents on the basis of truly daft ideologies, as likely as The question quite simply is whether the theory is not based on some mutant French philosophie.And complete. At heart are the questions as to what life is should the conversation stray to science, they might itself and the nature of the organizational principles politely enquire as to the current progress in our that might underpin it. The first topic was most understanding, say, of quantum entanglement. famously articulated by Schro¨dinger (1948), and con- Yet, if evolution is glaringly obvious, why is it not tinues to receive attention, albeit at times in a only greeted with growing hostility, but the siren-call somewhat desultory (if not unfocused) fashion. But of anti-evolutionary dogma, notably ‘intelligent the question is of central importance and a recent design’, remains a rallying point to individuals that in and highly germane articulation is given by Macklem any other respect fail to manifest any obvious sign of (2008). As he points out, life seems to occupy a very mental instability? The reasons, of course, are complex precise zone (indeed, I suspect a gossamer-like tight- rope) perched between systems that are either very highly ordered (crystalline) or largely chaotic and sub- *[email protected] ject to recurrent instabilities. As he concludes, One contribution of 19 to a Theme Issue ‘Personal perspectives in ‘understanding life requires knowledge of how the the life sciences for the Royal Society’s 350th anniversary’. design of living creatures and emergent phenomena, 133 This journal is q 2010 The Royal Society Downloaded from rstb.royalsocietypublishing.org on October 31, 2010 134 S. Conway Morris Review. Evolution is predictable appearing spontaneously in self-ordered, reproducing, striking convergences (Bossuyt & Milinkovich 2000) interacting, energy-consuming, nonlinear, dynamic with the frogs of Asia (principally India), and so too ensembles makes us what we are. I believe this will in this latter region there are further episodes of paral- be the next biological revolution’ (Macklem 2008, lel evolution (e.g. independent development of fangs). p. 1846). This writer also emphasizes the central role The comparisons between Madagascan and Asian of emergence in biological systems. Together with frogs are all the more striking because they extend to the related topic of self-organization, these concepts the larval forms, but there is one striking omission. can be melded with the currency of evolution in the Thus, in Asia there is no counterpart to the iconic form of developmental constraints (the role of which poisonous mantellids. So, the principle of the repeat- may be exaggerated) and epigenetics to suggest that ability of evolution fails at the first hurdle? Not quite, indeed something is missing in the Darwinian because the mantellids display a series of striking synthesis. convergences with the neotropical dendrobatids Here, I will suggest that one central tenet of the cur- (poison-arrow frogs; e.g. Clark et al. 2005). rent neo-Darwinian synthesis, that evolution is for all The question, therefore, is how far does this prin- intents and purposes open-ended and indeterminate ciple extend? To be sure, the evidence is that both in terms of predictable outcomes, is now open to ques- frogs and amphibians (and indeed vertebrates and tion. Thus, not only is life suspended between animals) are monophyletic, yet in each and every permanently uninhabitable regions that are either case the assemblage of the body plans (at whatever locked into crystalline immobility or in continuous taxonomic level; Conway Morris 2002) reveals a com- and chaotic flux, but that the lines of evolutionary plex (and often controversial) story of stem groups vitality thread through a landscape that leaves evol- typified by striking parallels in evolutionary direction- ution with surprisingly few choices. The basis of this ality. In addition, although widely remarked upon the view relies on the phenomenon of evolutionary conver- general observation that early in the evolution of a gence. This concept is, of course, not only entirely group there is very often a me´lange of ‘unexpected’ familiar to evolutionary biologists, but also provides features, leading to repeated remarks of ‘bizarre’ mor- some of the strongest arguments in favour of adapta- phologies and ‘problematic relationships’, is actually tional explanations. However, much less appreciated one of profound evolutionary importance. A recent is the ubiquity of this convergence, with examples example involves a new reptile close to the origin of spanning the entire biological hierarchy from mol- the birds (Zhang et al. 2008), which in turn underlines ecules to social systems and cognitive processes. In some important generalizations. Thus, when we con- support of this thesis, which I explore at far greater sider the origin of the birds, the story of Archaeopteryx length elsewhere, I briefly touch on (i) what, if any, and its theropod connection, not to mention the specta- key steps in the evolution of life are entirely fortuitous cular evidence of subsequent bird evolution in the and (ii) what, if any, biological innovations are unique? Cretaceous (e.g. Ji & Ji 2007; Zhou et al. 2008), needs no emphasis. Perhaps, less well appreciated is that within this group the Late Cretaceous genus 2. ARE THE KEY STEPS IN EVOLUTION Rahonavis ostromi, initially interpreted as a primitive FORTUITOUS? bird (Foster et al. 1998a,b; see also Zhou 2004), and If there is a fatal flaw in the argument for evolutionary indeed coexisting in Madagascar with genuine birds inevitabilities, if not a determinism, then it is in the (Foster et al.