book reviews sectors producing new technologies and Sankar Chatterjee joins Lowell Dingus and products can be properly managed and pub- Timothy Rowe in adopting a militant point licly overseen to avoid ecological, ethical or Living with dinosaurs of view, describing how the pressures human-health mishaps. The Rise of Birds: 225 Million Years applied by man have led to the extinction of Some of this complexity is acknowledged of Evolution hundreds of modern dinosaur species. The in the final chapter, “A personal note”, in by Sankar Chatterjee causes of the K/T extinction are still under which Rifkin writes of using science, and even Johns Hopkins University Press: 1998. debate, but it is clear that man has caused genetics, in a manner that respects our natur- Pp. 312. $39.95, £33 many extinctions in the Holocene. al world: “the question is what kind of The Mistaken Extinction: Dinosaur Chatterjee concludes that the impact biotechnologies will we choose in the coming Evolution and the Origin of Birds hypothesis was the proximate cause of the8 Biotech Century?” Our greatest challenge lies by Lowell Dingus and Timothy Rowe K/T biotic crisis, while volcanic phenomena in the social guidance and assessment of W. H. Freeman: 1997. Pp. 332. $34.95, increased the climatic stress and enhanced biotechnology within a democratic partici- £24.95 the extinction process. Dingus and Rowe patory framework and a global awareness. Taking Wing: Archaeopteryx and the review earlier hypotheses about the K/T Rifkin was criticized 20 years ago for exag- Evolution of Bird Flight biotic crisis, and then contrast the volcanic gerating the untoward paths biotechnology by Pat Shipman and impact hypotheses and revise the pat- would take and for opposing scientific Simon and Schuster: 1998. Pp. 336. $25. To terns of extinction and survival. A clear con- progress. In hindsight, many of his predic- be published in the United Kingdom in June sensus has yet to emerge, but many present- tions can hardly be considered hyperbole. by Weidenfeld and Nicolson, £20 day researchers consider that the extinction Serious discussions are taking place on José Luis Sanz, Bernardino P. Pérez- of non-avian dinosaurs was caused by a cloning humans, altering human germ cells, Moreno and Francisco J. Poyato-Ariza combination of the volcanic/marine regres- universal genetic screening, mandatory DNA sion and impact hypotheses. So large identification and even the unmentionable In recent years there has been a renaissance in extraterrestrial impacts and massive erup- prospect of ‘improving’ the human gene pool. Mesozoic palaeo-ornithology. This kind of tions of flood basalts have to be considered. In his role as social critic of biotech- reinvigoration is normal in palaeontology, The historical diversity of a group of liv- nology, Rifkin has become entangled in a as new discoveries show that old hypotheses ing organisms is shaped by extinction and paradoxical situation. In an attempt to stir are false and give rise to new ones. A large diversification, the pattern of which is the reader’s passions, he overdramatizes in number of Mesozoic avian taxa have been mapped by a phylogenetic hypothesis. The some sections the power of biotechnology: discovered during the past 20 years, so it is discovery of new fossils shows that the phy- “The biotechnology revolution will affect perhaps not surprising that three books logenetic history of Mesozoic birds is much each of us more directly, forcefully, and devoted to Mesozoic palaeo-ornithology more complex than previously thought. intimately than any other technology revolu- have recently been published. They are dif- Chatterjee agrees with Dingus and Rowe — tion in history.” We must be reminded that ferent in structure and scope, but the main and most palaeo-ornithologists — that the the first three main agricultural products topics of each are the foremost areas of phylogenetic map of birds is shaped by a of genetic engineering — the Flavr Savr research on the early evolutionary history of series of successive sister taxa from tomato, the Ice Minus bacterium and recom- birds: the origin and historical diversity of Archaeopteryx to Neornithes (extant birds). binant bovine growth hormone — have the avian clade, its phylogenetic relation- Like that of Dingus and Rowe, the avian phy- either failed or are failing. ships, and the development of flight. logenetic hypothesis put forward by Pat Moreover, like many of the genetic scien- One of the most stimulating ideas arising Shipman is within the consensus reached by tists he calls to task, Rifkin at times accepts from vertebrate palaeontology is the most researchers. uncritically a view that vastly overestimates dinosaurian origin of birds. Proposed by Chatterjee, however, includes a problem- the importance of genes in biological organ- Thomas Huxley in 1868, and reformulated atic taxon, the Triassic Protoavis, which is the isms. (“With genetic engineering, we assume by John Ostrom in the 1970s, this hypothesis core of his book. He positions this enigmatic control over the hereditary blueprint of life is now widely accepted, and is supported by a genus between Archaeopteryx and the Enan- itself.”) If he were to question too seriously large amount of evidence that increases as tiornithes, implying that Protoavis is a basal the ability of science to carry out its “redesign new fossil forms are discovered. All three bird but is more derived than Archaeopteryx. of nature”, the book would lose much of its books favour this hypothesis, which is chal- The combination of characters of Protoavis moral force. But, while he plays up the power lenged nowadays by just a few researchers. In is very unusual because, according to Chat- of genes (“the ultimate exercise of power”) in terms of current phylogenetic systematics, terjee’s interpretation, it has an ornitho- some sections, elsewhere he tempers that the dinosaurian origin hypothesis implies thoracine-like pectoral region associated view by acknowledging the poverty of that birds have to be considered as short- with a very primitive (basal archosaur-like) genetic reductionism. He points out that, tailed, feathered volant dinosaurs. hand architecture. This combination chal- although such a view may be false, it has The interpretation of birds as present- lenges the transformation sequence of char- helped to advance the interests of those day dinosaurs leads to the provocative idea acters in early avian evolutionary history. involved in molecular biology. that dinosaurs have been around ever since If Protoavis was a bird (between 60 mil- There is no simple reading of this book. A humans appeared on Earth, and therefore lion and 70 million years older than fair-minded reader will agree with some represent an important part of our natural, Archaeopteryx), this hypothesis predicts points and disagree with others. At a time cultural and economic environment. So it is important modifications even in the evolu- when scientific institutions are struggling not surprising that palaeontologists are tionary history of non-avian dinosaurs. A with the public understanding of science, concerned by man’s responsibility in the problematic consequence is that even there is much they can learn from Rifkin’s disappearance of extant dinosaurs, given derived theropod groups, such as dro- success as a public communicator of scientif- that natural phenomena — the Creta- maeosaurids, troodontids or tyran- ic and technological trends. ceous/Tertiary (K/T) biotic crisis — extin- nosaurids, must appear during the Lower or Sheldon Krimsky is in the Department of Urban guished most of the diversity of Upper Middle Triassic. Chatterjee’s answer to this and Environmental Policy, Tufts University, Cretaceous dinosaurs (including some avian troubling idea is highly classical: imperfec- 97 Talbot Avenue, Medford, Massachusetts ones, such as Enantiornithes, Hesperor- tion and sampling scarcity in the fossil 02155, USA. nithiformes and Ichthyornithiformes). record. Nevertheless, that tyrannosaurids

32 NATURE | VOL 393 | 7 MAY 1998 Nature © Macmillan Publishers Ltd 1998 book reviews are about the same age or even older than the first known dinosaurs, such as Eoraptor or Fishing for solutions the herrerasaurids, seems improbable. So where does Protoavis fit in? It could be “While fisheries around a taphonomic assemblage of different ani- the world are in trouble, mals. But there are some bony elements that it’s not too late to turn the clearly exhibit bird-like characters. The Pro- tide,” we read in Faces of toavis evidence could also suggest either the Fishing: People, Food and presence in the Upper Triassic of a non-avian the Sea at the Beginning of theropod or other archosaur with conver- the 21st Century 8 gent bird traits, or the appearance of the (Monterey Bay Aquarium, avian clade more than 200 million years ago. $19.95). Bradford Matsen Present-day evidence is much more consis- presents both the tent with the first hypothesis. problems and potential Although all three books fit in with the remedies, in a book based consensus that birds are flying dinosaurs, on images collected for an there are differences in their proposals about exhibition held by the the origin of flight. There are two hypotheses Californian aquarium. to account for the origin of flight: “from the trees down” (usually associated with a non- survey of the most relevant alternative A commendable feature of the book by dinosaurian ancestor of birds), and “from the hypotheses, but Chatterjee’s is different Cynthia Rosenzweig and Daniel Hillel is ground up” (usually associated with a because most of the main hypotheses are his their readiness to face the complex factors dinosaurian ancestor of birds). Shipman own and are not widely accepted. that will influence the agriculture of the agrees with Dingus and Rowe in maintaining José Luis Sanz, Bernardino P. Pérez-Moreno and future. Consider, for example, the conse- the consensus on the origin of flight, follow- Francisco J. Poyato-Ariza are in the Unidad de quences of altered attitudes to energy ing the “from the ground up” hypothesis, Paleontología, Departamento de Biología, production resulting from efforts to avoid suggesting that avian flight originated from a Facultad de Ciencias, Universidad Autónoma de carbon emissions to the atmosphere. cursorial biped (a theropod dinosaur), Madrid, 28049 Madrid, Spain. Energy-expensive agrochemicals will be whereas Chatterjee suggests a new synthesis, avoided, reduced tillage agriculture will be proposing a dinosaurian ancestor of birds and demanded, biomass energy plantations may a “from the trees down” origin of flight. He compete with food production, extra land considers some theropod clades, commonly Farming forecast may be flooded for hydro-development, and thought to be highly cursorial animals, as Climate Change and the Global so on. Rosenzweig and Hillel take great pains arboreal ones. This requires new functional Harvest: Potential Impacts of the to document the involvement of agricultural interpretations of some structures: for exam- Greenhouse Effect on Agriculture processes in the emission and control of ple, the stiffened caudal appendage must be by Cynthia Rosenzweig and Daniel Hillel greenhouse gases into the atmosphere and reinterpreted as a climbing prop. Neverthe- Oxford University Press: 1998. Pp. 324. the consequent feedback effects of agricul- less, there are no features that clearly indicate £49.50, $65 tural change. an arboreal habitat for theropods such as Peter D. Moore The response of a crop to environmental ornithomimids, whereas nearly every feature change can be investigated in several ways. indicates that they are extremely well adapted The public expect science to be predictive, The use of controlled environment cham- for high-speed running. but most scientists are sufficiently aware of bers has many advantages, such as precise Shipman makes an outstanding analysis their own ignorance to avoid prediction factor control, but may not adequately simu- of the contribution of Archaeopteryx to dis- wherever possible and to qualify it with wide late conditions of soil evaporation. Field cussions about the origin of flight. She con- error margins if speculation is unavoidable. experiments using open-topped enclosures siders the subject from the impartial point of Agricultural scientists are among those of have been more satisfactory, but even this view of someone from another research field. whom most is demanded by politicians and approach has disadvantages, such as the dif- This allows her, after analysing all the the public, yet they face some of the greatest ficulty in investigating the interactive effect hypotheses, to reach a conclusion based problems in prediction, as they deal with sev- of increased carbon dioxide at different tem- mainly on a functional approach: that birds eral levels of compounded errors. peratures. There is also the problem of scal- come from a cursorial theropod ancestor. They inherit the innate uncertainties of ing up from such data in a world of varied Shipman’s book is an accessible, yet pre- climate prediction and also have to scale up microclimate and soil conditions. Such soil cise, account. It provides a solid background to global levels from small-scale experiments variations may mean that the potential to the importance of Archaeopteryx for on the responses of crop plants to simulated advantages of higher carbon dioxide levels understanding the origin of avian flight, and sets of conditions. They then need to account for plant growth will not occur in many is suitable for specialists and non-specialists. for the simultaneous responses of weeds, regions because of soil nutrient limitation. Dingus and Rowe focus on dinosaurs, deal- pests and diseases to the new conditions Using recent experience of atmospheric ing with birds and the origin of flight within before they can assess the outcome of change and agricultural change to test the validity of the context of the K/T boundary extinctions. on global crop yields. As the geographical models appears superficially attractive, and They present much information, provide a pattern of agricultural practice inevitably one can calculate the expected increase in good phylogenetic background and use changes, there are also matters such as soil global agricultural yield as a result of increas- familiar language. They construct a hypo- conservation, wildlife habitat protection and ing atmospheric carbon dioxide levels from thetical, conceptual and methodological socioeconomic factors to consider, all of 280 to 360 p.p.m.v. (the observed change over framework that could be assumed by a large which differ from one area to another. Con- the past 200 years) at 7.5%. The problem is part of the scientific community. Chatterjee sidering all of these variables together, it is a that improved varieties of crops and takes a more specialist point of view. The brave author who is willing to write a book enhanced input of nitrogen to soils from other two books present a comprehensive about climate change and the global harvest. atmospheric pollution have also influenced

NATURE | VOL 393 | 7 MAY 1998 33 Nature © Macmillan Publishers Ltd 1998