spring books

Climbing the evolutionary tree The in the Tree: An Intellectual and Natural History of by Alan Walker & Pat Shipman Harvard University Press: 2005. 312 pp. $26.95, £17.95, €24.90 Peter Andrews The ape in the tree is Proconsul, a ape known exclusively from East . It has many things to recommend it as a subject for a book: it is the earliest known ape in the fossil record (dating from 18–20 million years ago); it is represented by the most complete remains of any fossil ape (several partial skeletons); and, since the first remains were found some 75 years ago, it has been studied by many people of dif- ferent levels of eminence. It is therefore a good subject on which to build any number of scientific edifices, whether historic, taxo- nomic, ecologic, phylogenetic or to do with functional morphology. What’s more, it has been at the centre of feuds, deaths, disputes over ownership, and rivalries between some of the biggest person- alities in anthropology. In many of these, Alan Walker has been involved at first hand, and its own way of life. This enlightened people as I could”. He is an inspired and and he brings a strongly personalized view of approach, free of the straitjacket of descen- inspiring teacher, but it is my regret, and these events to this book. It is first and fore- dent species, is the most successful aspect of the subject’s loss, that he has not himself most an account of his own involvement this book in documenting the way of life of produced a monographic treatment of Pro- with the discovery and description of some Proconsul in all its aspects. consul and its place in ape to of the best specimens of Proconsul yet found. Having said this, Walker makes it clear match Napier’s. The present book is not an The account is actually written by Alan’s right from the start that this is no scientific adequate replacement,however entertaining wife, Pat Shipman, but it is curiously written treatise, but a semi-popular account of early it may be. in the first person singular as if by Walker, ape evolution. His mentor was John Napier, There is also a failure to extend the and we learn as much about him in this book a larger-than-life character who had enor- approach of functional morphology to its as we do about the place of Proconsul in the mous influence on studies in the third aspect: interaction with the environ- evolution of the . middle of the twentieth century. One of ment. There is little more than anecdotal One of Walker’s many gifts is his ability to Napier’s major works was a monograph — discussion about the environment that Pro- illuminate subjects he is interested in and to The Fore-limb Skeleton and Associated consul lived in, other than saying that there bring new ideas to bear.His stated aim in this Remains of (British was forest and trees for it to move around in. book is to provoke curiosity about apes and Museum (Natural History), 1959) — on the The apparent link to forest environments the part they have played in our evolutionary partial skeleton of Proconsul from Rusinga is important for Walker’s reconstruction of past. He recognizes that we should not view Island, which provides a detailed morpho- Proconsul’s way of life,for it implies a reliance fossil apes in some sense as ‘failed apes’.There logical description with the emphasis on the on tree-living. that live in wood- is a tendency among some workers,both past function of the as a whole. Napier’s land rather than forests, by contrast, are and present, to try and identify fossil apes approach to functional morphology was more terrestrial, as the tree canopies are too with their living survivors — , hugely influential and made a great impres- open and too poor in resources to support gorillas and orangutans — so the common sion on Walker, who has carried on and fruit-eating all year round. ancestor of and chimpanzees, for extended this approach with the help of a Walker does not mention a wealth of example, is seen by some as having been succession of bright,enthusiastic students. published environmental evidence, much of -like. The study of functional morphology is it done in the 1970s,a period of study excised Walker does not address this particular based on interdisciplinary collaboration: from his account of Proconsul studies, and issue directly, for he is dealing with a fossil morphology is interpreted in terms of func- some that he does mention is now thought ape that lived close to the time when mon- tion, function in terms of behaviour, and to be wrong. For example, much of the evi- keys and apes diverged (about 20 million behaviour in terms of interaction with the dence for the environment at Rusinga, based years ago), but he states unequivocally that environment. This requires a high level of on both plants and faunas, shows the common ancestor of monkeys and apes collaboration that is entirely in line with that the area was dominated by seasonal was neither monkey nor ape but a being Walker’s stated intention to “give as many deciduous woodlands with patches of forest in itself that had its own suite of characters opportunities to up and coming young that were almost certainly ephemeral both

24 NATURE | VOL 435 | 5 MAY 2005 | www.nature.com/nature © 2005 Nature Publishing Group spring books in time and space. The strong evidence for the meteoric rise and fall of the arrogant, reef hypothesis. He proposed that reefs grew forest environments comes from other sites: narcissistic and charismatic Louis, and his not on their own debris, but on the accumu- Songhor and Koru, based on abundant relationship with his shy and diligent son. lation of sediment derived from plankton mammalian faunas, and Mfangano, based Louis, a palaeontologist, was the first to and other non-coral skeletons. Alexander on the fruits of tropical forest trees. The evi- propose that an ice age could explain many Agassiz was immediately drawn to this idea: dence for forest at Rusinga is based on local- features of the Earth’s surface. In the mid- it was born of neither his father’s idealism ized outcrops of forest faunas, abundant nineteenth-century United States, which nor Darwin’s over-simple theorizing, but woody climbers, which typically would have was hungry for pioneering personalities seemed instead to be based firmly on observ- been growing locally along water courses, that embodied the spirit of a young nation, able fact. Alexander, grief-stricken by the and leaves with apparent (not yet analysed) Louis’ enormous energy and persuasive early loss of his wife and other relatives, had forest affinities. The so-called fruit-and-nut vision enabled him to found many scien- finally found his raison d’être: to disprove bed, which Walker mentions several times tific institutions that still thrive today. Darwin’s theory. as providing evidence of forest, is actually Darwin, by contrast, is presented as a dis- Made hugely wealthy from the owner- dominated by plant species with deciduous tant figure, more a man with a following ship of copper mines, Alexander was able to woodland affinities. The idea of Proconsul than a personality. embark on a massive programme of travel. as a slow climber subsisting mainly on a diet It was Louis’failure For decades he made detailed observations of soft fruits, as indicated by its functional to embrace the impli- of all the known coral reefs. He was morphology, is less viable if it lived in a cations of Darwin’s Ori- convinced that each deciduous woodland environment, rather gin of the Species, instead reef was a than a forest. tenaciously Walker’s semi-popular account of this holding on to important fossil ape will be an accessible and hisidealistic logic entertaining read for the educated layman. that God had created It will also be a useful guide to students all species whole and learning about how research is conducted, immutable, that toppled him from his although they need to be aware of the pedestal in American scientific and Boston idiosyncracies in this highly personalized blue-blood society.In just five years Louis was account. We can live in hope that Walker transformed from being seen as the prince will do justice to his great abilities and will of US science to an archaic reactionary. yet produce a definitive account of this ape As a young man, Alexander was in the tree. ■ caught between paternal loyalty and Peter Andrews is in the Department of a great personal need for objective Palaeontology, The Natural History Museum, and careful analysis. He rejected his Cromwell Road, London SW7 5BD, UK. father’s florid unscientific style but was equally unhappy with Darwin’s theorizing, which was based, as Alexander saw it, on equally unacceptable flights of imagination, rather than on the tireless compilation of The evolution of meticulously observed facts. Darwin had been greatly influenced scientific thinking by the geologist Charles Lyell, whose Reef Madness: Charles Darwin, major tenet was that geological structures, Alexander Agassiz, and the rather than being the result of past catastro- Meaning of Coral phes, were instead formed by the constant unique outcome of forces that combined in by David Dobbs action of slow and gradual processes observ- different ways: no single grand theory was Pantheon Books: 2005. 306 pp. $25 able today. It is easy to see how such thinking required.By 1902,he believed he had proved Rachel Wood led to Darwin’s formulation of another time- Murray’s theory. Yet astonishingly, after his based phenomenon: the origin of multiple death in 1910, no manuscript that summa- Reefs have long fascinated natural histori- species through common descent by means rized his massive accumulation of obser- ans and geologists for their unearthly beauty, of natural selection. Darwin’s observation of vations was ever found. It seems that for as well as their ability to produce prodigious Pacific reefs, together with his harrowing Alexander,the chase was everything. amounts of carbonate sediment. Yet reefs experiences of the Earth-moving forces of The truth is that there were never enough offer more than their share of paradoxes. earthquakes during the voyage of the Beagle, facts to go on. All the protagonists had died How do coral-reef islands seemingly grow led him to propose that oceanic reefs and long before the origin of reefs was resolved from great depths in the middle of the atolls were formed on subsiding founda- by deep drilling in the 1950s. The penetra- oceans? What controls the production of all tions, such as volcanoes. His imaginative tion of Eniwetok atoll down to its volcanic this limestone? And why do so many reefs intellect saw here another result of small foundations revealed some 1,500 metres of form necklaces strung across the Pacific? changes that could account for otherwise coral reef limestone,proving Darwin right. These questions troubled the minds of complex patterns: that there was a dynamic Reef Madness is more than a narrative nineteenth-century scientists and philos- relationship between the reefs and their about the victory of empiricism, the power ophers. The long, tortured and often sad foundations that seemed to shape them. But of observation as the evidence of truth, over history of how the ‘coral reef problem’ was proof for this theory was there none. the philosophy of belief. It is also a beautiful finally solved is laid bare in this eloquent So the stage was set for a century-long illustration of how theories can, or must, be and thoughtful book. battle for the roles of empiricism, theorizing built slowly and painfully,brick by brick, by We are first introduced to the key fig- and imagination in scientific endeavour. a dynamic combination of both imaginative ures: Louis Agassiz, his son Alexander and In 1876, the Scottish oceanographer John leaps and factual observation. It would be Charles Darwin. The book explores in detail Murray had put forward an alterative coral- foolish to think that this debate has ended: as

NATURE | VOL 435 | 5 MAY 2005 | www.nature.com/nature 25 © 2005 Nature Publishing Group