- Email: [email protected]
Cherchez le Darwinism
Update invertebrates, plants and vertebrates are better covered in Part III on sexual clonality. In part, this is perhaps because there are fewer vertebrate examples to consider: armadillos in the case of clonality by polyembryony, and the hermaphroditic mangrove killifish in the case of clonality by extreme inbreeding (self-fertilization). In this section, Avise quotes the botanist Herbert G. Baker, who noted that when identical conclusions are derived from plants and animals, ‘one cannot restrain from feeling that a principle of more than superficial importance has been uncovered’ [5]. This quote is relevant to cases of sexual and asexual clonality alike. In summary, ‘Clonality’ is a highly entertaining and thought-provoking book from a master of the field of evolutionary genetics. It provides an accessible entry point to understanding the world of clonal reproduction and also takes a novel perspective by tackling clonality as a general theme, whereas previous treatments of clonally reproducing taxa have focussed on sex versus asex. Avise’s
Trends in Ecology and Evolution
Vol.24 No.9
perspective emphasizes how clonality is a widespread phenomenon across many levels of biological organization. However, it also reiterates the well-established notion that, despite its short-term success, clonality on its own is doomed in the long term. References 1 Wilmut, I. et al. (1997) Viable offspring derived from fetal and adult mammalian cells. Nature 385, 810–813 2 Avise, J.C. et al. (1992) Molecular clones within organismal clones: mitochondrial DNA phylogenies and the evolutionary histories of unisexual vertebrates. Evol. Biol. 26, 225–246 3 Stebbins, G.L. (1985) Polyploidy, hybridization, and the invasion of new habitats. Ann. Miss. Bot. Gard. 72, 824–832 4 Suomalainen, E. et al. (1987) Cytology and Evolution in Parthenogenesis. CRC Press 5 Baker, H.G. (1955) Self-compatibility and establishment after ‘long-distance’ dispersal. Evolution Int. J. Org. Evolution 9, 347–349
0169-5347/$ – see front matter ß 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2009.04.003 Available online 18 May 2009
Book review
Cherchez le Darwinism How Life Began: Evolution’s Three Geneses by Alexandre Meinesz; translated by Daniel Simberloff. The University of Chicago Press, 2008. US$27.50 hbk (282 pages) ISBN: 978 0 226 51931 9
Simon Conway Morris Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, England
There have been many attempts to make evolution not only our master narrative, but also our foundational myth. This has entailed, of course, both the bulldozing of the Genesis stories, and the dynamiting (with ill-disguised glee) of the Edenic vision. A world full of meaning and purpose has been traded for a pitiless, hostile and competitive universe. Yet ironically, although repeatedly claiming to be meaningless at heart, the darwinian world-picture itself strives to retain an almost cosmic (or is it comic?) saga of our ascent from slime. Paradoxically central to this enterprise is the insistence that, for all intents and purposes, the whole darwinian drama is one glorious accident, one damn thing after another. To the first approximation, Alexandre Meinesz stands full square in this tradition, with his narrative littered with references to the fortuitous and contingent. Yet towards the end of How Life Began, perhaps to my surprise, I read how ‘We must also find in spirituality and in ideologies new support that will allow frank and thorough consideration of the scientific evidence on the history of the geneses of life and its past evolution’. To be sure, the immediate reference is how to awaken people’s awareness to the looming environmental catastrophe, but Meinesz stems from a different Corresponding author: Conway Morris, S. ([email protected]).
philosophical tradition. This is one that favours the discourse of reason above irritating Anglo-Saxon pragmatism. So Meinesz can cheerfully draw attention to the ‘freedom arising from the French Revolution’, rather than a more realistic analysis of this disaster representing the fulcrum point in the European pursuit of totalitarian catastrophe. Neither is this the only point where the narrative remains entertainingly Gallic. Thus, Meinesz whisks us, in the very best tradition of popular science writing, to the wonders (and discomforts) of a remote research station. Here the culinary prospects of enjoying moules marinie`re (and maybe a glass of Chablis?) rudely run into the buffers of the island being ‘sacred’ territory. Alas, Meinesz has to manage with that great American delicacy, a roast marshmallow on a stick. So Meinesz does his best to enliven the text and his perspective, although too often subscribing to some customary pieties, does allow us a refreshing canter through evolution. Enthusiastic, yes, but always in the background is the pedagogue. So, although his attempt to import the Dutch painter Vermeer and his mysteriously transcendental canvases into a cultural context of knowledge and ignorance does not quite work, he tries repeatedly to elevate the narrative to some more thought-provoking possibilities. Indeed, one senses that, at times, the author feels himself to hover on the edge of greater mysteries. This is most obvious, perhaps, in terms of his musings on panspermia. While rehearsing the well-known story of how Earth was possibly seeded by life-bearing meteorites, 479
Update Meinesz seems to be groping towards some wider vision. ‘Life came from elsewhere’ he exclaims, but the sense that the galaxy is strewn with life becomes in his eyes all the more mysterious given that all our attempts to understand the origins of life have reached an almost total impasse. That, however, does not make the author either a pantheist or a vitalist; rather I think we see a stoic. And that, as he stresses, has much to recommend it: Balance! but arrived at by chance, Beauty! but perhaps only the eye of the beholder. But does Meinesz really provide with a really new vision? Of course How Life Began is as darwinian as the rest of us, but too often it is littered with entirely unjustified assumptions. Thus, his analysis, if that is not too bold a word, of how we became self-conscious is so simplistic as to be painful. The trouble with this sort of narrative, where a slightly brighter ape astonishes his bystanders by chucking a rock at an unwary animal, thereby leading to better quality suppers and tons of
Trends in Ecology and Evolution Vol.24 No.9
children, is put in a gaspingly simple story of better genes. So too, and perhaps more surprisingly, the author is not only puzzled as to how complex forms might emerge, but is also hardly aware that the idea of things starting off terribly simple might be looking decidedly wobbly. In fact, generally speaking as far back as we can see, the first forms not only turn out to be remarkably complex, but also probably self-assembled with speed and efficiency. Meinesz has provided some refreshing insights drawn from a perspective that is more holistic than so much of the dreary tub-thumping of the ultra-darwinists. However, the fact remains that, as a synthesis for the darwinian programme in the 21st century, this book is a mile-stone, but the goal still lies over the horizon.
0169-5347/$ – see front matter ß 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2009.04.001 Available online 22 April 2009
Book review
Is it time for timetrees? The Timetree of Life edited by S. Blair Hedges and Sudhir Kumar. Oxford University Press, 2009. £100.00, hbk (576 pages) ISBN: 978 0 19 953503 3
Frank E. Anderson Department of Zoology, Southern Illinois University, Carbondale, Illinois 62901, USA
Anchoring phylogenies to absolute time has been a major goal of systematists since Darwin, and efforts to do so have exploded with the rise of molecular phylogenetics. Unfortunately, numerous factors complicate these efforts, including how to model changes in the rate of molecular evolution [1,2] and how to incorporate fossil data [3], which constitute the primary bases of rate calibrations. Substantial progress has been made on these fronts recently, and the development of ‘relaxed clock’ methods has been particularly important. However, the flexibility provided by these new methods comes at a cost: a wide range of date estimates can be generated from the same data by using different methods [4,5]. Into this tumult comes The Timetree of Life, a volume edited by S. Blair Hedges and Sudhir Kumar. Hedges and Kumar have been major players in this field for nearly two decades, publishing divergence time estimates for a wide array of taxa [6] and generating some controversy in the process [7,8]. The book is split into two sections: an introductory section comprising overviews of the history, methodology and utility of divergence time estimation; and a ‘Timetrees’ section comprising taxon-specific chapters, each featuring an overview of the focal taxon and a dated phylogeny (a ‘timetree’). Corresponding author: Anderson, F.E. ([email protected]).
480
Some of the introductory chapters are valuable reviews of the uses of timetrees and of the methods used to produce them. For example, Benton et al. summarize the use of fossils to calibrate timetrees. This is a central issue in timetree estimation, but there has been substantial confusion regarding how fossil data should be used in this context. Fossils can be used to provide upper bounds for divergence times (the divergence between the chimp and human lineages, for example, cannot have occurred more recently than the earliest hominid fossil). Lower bounds for divergence times can also be estimated using fossils, but this is not straightforward. Benton et al. address these issues, and also present minimum and maximum dates (and supporting fossil evidence) for 65 nodes across animal phylogeny. This chapter is a superb resource for zoologists, but it should also be useful to anyone interested in learning a paleontological perspective on timetree construction. Unfortunately, other introductory chapters are not so informative. Avise presents a brief synopsis of the potential uses of timetrees, but many of these uses will be obvious to most readers. By contrast, Gradstein and Ogg describe the methods used to develop the geological timescale, a process that is anything but obvious to most biologists. As such, this chapter could have been a fantastic primer, but instead I found it to be rather abstruse. The timetree chapters, written by experts on each taxon, make up the bulk of the book. The taxonomic coverage of these chapters is understandably scattershot (vertebrates, plants and arthropods are well represented; fungi,
Trends in Ecology and Evolution
Vol.24 No.9
perspective emphasizes how clonality is a widespread phenomenon across many levels of biological organization. However, it also reiterates the well-established notion that, despite its short-term success, clonality on its own is doomed in the long term. References 1 Wilmut, I. et al. (1997) Viable offspring derived from fetal and adult mammalian cells. Nature 385, 810–813 2 Avise, J.C. et al. (1992) Molecular clones within organismal clones: mitochondrial DNA phylogenies and the evolutionary histories of unisexual vertebrates. Evol. Biol. 26, 225–246 3 Stebbins, G.L. (1985) Polyploidy, hybridization, and the invasion of new habitats. Ann. Miss. Bot. Gard. 72, 824–832 4 Suomalainen, E. et al. (1987) Cytology and Evolution in Parthenogenesis. CRC Press 5 Baker, H.G. (1955) Self-compatibility and establishment after ‘long-distance’ dispersal. Evolution Int. J. Org. Evolution 9, 347–349
0169-5347/$ – see front matter ß 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2009.04.003 Available online 18 May 2009
Book review
Cherchez le Darwinism How Life Began: Evolution’s Three Geneses by Alexandre Meinesz; translated by Daniel Simberloff. The University of Chicago Press, 2008. US$27.50 hbk (282 pages) ISBN: 978 0 226 51931 9
Simon Conway Morris Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, England
There have been many attempts to make evolution not only our master narrative, but also our foundational myth. This has entailed, of course, both the bulldozing of the Genesis stories, and the dynamiting (with ill-disguised glee) of the Edenic vision. A world full of meaning and purpose has been traded for a pitiless, hostile and competitive universe. Yet ironically, although repeatedly claiming to be meaningless at heart, the darwinian world-picture itself strives to retain an almost cosmic (or is it comic?) saga of our ascent from slime. Paradoxically central to this enterprise is the insistence that, for all intents and purposes, the whole darwinian drama is one glorious accident, one damn thing after another. To the first approximation, Alexandre Meinesz stands full square in this tradition, with his narrative littered with references to the fortuitous and contingent. Yet towards the end of How Life Began, perhaps to my surprise, I read how ‘We must also find in spirituality and in ideologies new support that will allow frank and thorough consideration of the scientific evidence on the history of the geneses of life and its past evolution’. To be sure, the immediate reference is how to awaken people’s awareness to the looming environmental catastrophe, but Meinesz stems from a different Corresponding author: Conway Morris, S. ([email protected]).
philosophical tradition. This is one that favours the discourse of reason above irritating Anglo-Saxon pragmatism. So Meinesz can cheerfully draw attention to the ‘freedom arising from the French Revolution’, rather than a more realistic analysis of this disaster representing the fulcrum point in the European pursuit of totalitarian catastrophe. Neither is this the only point where the narrative remains entertainingly Gallic. Thus, Meinesz whisks us, in the very best tradition of popular science writing, to the wonders (and discomforts) of a remote research station. Here the culinary prospects of enjoying moules marinie`re (and maybe a glass of Chablis?) rudely run into the buffers of the island being ‘sacred’ territory. Alas, Meinesz has to manage with that great American delicacy, a roast marshmallow on a stick. So Meinesz does his best to enliven the text and his perspective, although too often subscribing to some customary pieties, does allow us a refreshing canter through evolution. Enthusiastic, yes, but always in the background is the pedagogue. So, although his attempt to import the Dutch painter Vermeer and his mysteriously transcendental canvases into a cultural context of knowledge and ignorance does not quite work, he tries repeatedly to elevate the narrative to some more thought-provoking possibilities. Indeed, one senses that, at times, the author feels himself to hover on the edge of greater mysteries. This is most obvious, perhaps, in terms of his musings on panspermia. While rehearsing the well-known story of how Earth was possibly seeded by life-bearing meteorites, 479
Update Meinesz seems to be groping towards some wider vision. ‘Life came from elsewhere’ he exclaims, but the sense that the galaxy is strewn with life becomes in his eyes all the more mysterious given that all our attempts to understand the origins of life have reached an almost total impasse. That, however, does not make the author either a pantheist or a vitalist; rather I think we see a stoic. And that, as he stresses, has much to recommend it: Balance! but arrived at by chance, Beauty! but perhaps only the eye of the beholder. But does Meinesz really provide with a really new vision? Of course How Life Began is as darwinian as the rest of us, but too often it is littered with entirely unjustified assumptions. Thus, his analysis, if that is not too bold a word, of how we became self-conscious is so simplistic as to be painful. The trouble with this sort of narrative, where a slightly brighter ape astonishes his bystanders by chucking a rock at an unwary animal, thereby leading to better quality suppers and tons of
Trends in Ecology and Evolution Vol.24 No.9
children, is put in a gaspingly simple story of better genes. So too, and perhaps more surprisingly, the author is not only puzzled as to how complex forms might emerge, but is also hardly aware that the idea of things starting off terribly simple might be looking decidedly wobbly. In fact, generally speaking as far back as we can see, the first forms not only turn out to be remarkably complex, but also probably self-assembled with speed and efficiency. Meinesz has provided some refreshing insights drawn from a perspective that is more holistic than so much of the dreary tub-thumping of the ultra-darwinists. However, the fact remains that, as a synthesis for the darwinian programme in the 21st century, this book is a mile-stone, but the goal still lies over the horizon.
0169-5347/$ – see front matter ß 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.tree.2009.04.001 Available online 22 April 2009
Book review
Is it time for timetrees? The Timetree of Life edited by S. Blair Hedges and Sudhir Kumar. Oxford University Press, 2009. £100.00, hbk (576 pages) ISBN: 978 0 19 953503 3
Frank E. Anderson Department of Zoology, Southern Illinois University, Carbondale, Illinois 62901, USA
Anchoring phylogenies to absolute time has been a major goal of systematists since Darwin, and efforts to do so have exploded with the rise of molecular phylogenetics. Unfortunately, numerous factors complicate these efforts, including how to model changes in the rate of molecular evolution [1,2] and how to incorporate fossil data [3], which constitute the primary bases of rate calibrations. Substantial progress has been made on these fronts recently, and the development of ‘relaxed clock’ methods has been particularly important. However, the flexibility provided by these new methods comes at a cost: a wide range of date estimates can be generated from the same data by using different methods [4,5]. Into this tumult comes The Timetree of Life, a volume edited by S. Blair Hedges and Sudhir Kumar. Hedges and Kumar have been major players in this field for nearly two decades, publishing divergence time estimates for a wide array of taxa [6] and generating some controversy in the process [7,8]. The book is split into two sections: an introductory section comprising overviews of the history, methodology and utility of divergence time estimation; and a ‘Timetrees’ section comprising taxon-specific chapters, each featuring an overview of the focal taxon and a dated phylogeny (a ‘timetree’). Corresponding author: Anderson, F.E. ([email protected]).
480
Some of the introductory chapters are valuable reviews of the uses of timetrees and of the methods used to produce them. For example, Benton et al. summarize the use of fossils to calibrate timetrees. This is a central issue in timetree estimation, but there has been substantial confusion regarding how fossil data should be used in this context. Fossils can be used to provide upper bounds for divergence times (the divergence between the chimp and human lineages, for example, cannot have occurred more recently than the earliest hominid fossil). Lower bounds for divergence times can also be estimated using fossils, but this is not straightforward. Benton et al. address these issues, and also present minimum and maximum dates (and supporting fossil evidence) for 65 nodes across animal phylogeny. This chapter is a superb resource for zoologists, but it should also be useful to anyone interested in learning a paleontological perspective on timetree construction. Unfortunately, other introductory chapters are not so informative. Avise presents a brief synopsis of the potential uses of timetrees, but many of these uses will be obvious to most readers. By contrast, Gradstein and Ogg describe the methods used to develop the geological timescale, a process that is anything but obvious to most biologists. As such, this chapter could have been a fantastic primer, but instead I found it to be rather abstruse. The timetree chapters, written by experts on each taxon, make up the bulk of the book. The taxonomic coverage of these chapters is understandably scattershot (vertebrates, plants and arthropods are well represented; fungi,