Foreign Visit Problems of Describing and Interpreting the Development of Land Vegetation Peter D

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Anyone who undertakes to survey a neural mechanisms of hearing and and ill-defined sketches of the outcome of field like this faces something of a singing, then acoustic behaviour and the palaeopedological research in this area. dilemma. The traditional method, which functions of calling, courtship and One palaeosol type for which there is is adopted by Ewing, arranges the subject aggressive songs. Finally, genetics and an abundance of information is the peaty by research technique: biophysics, evolution get the nod. Each group of soil (called entisol and histosol in the sensory physiology, motor physiology, insects receives its fair share of attention, US system). But Retallack again fails to ethology and evolution. On the one hand, depending on the amount of research that exploit this resource and his attempt to this makes it easy to compare species and has been done. This means that the Ortho­ define the times cales of peat accumulation to draw out general principles within each ptera are the dominant group, but others on the basis of peat thickness is positively subject area. On the other, it separates such as cicadas and the author's own misleading. To suggest that a peat depth things that clearly belong together, favourite, Drosophila, are not neglected. of under 40 centimetres indicates an age of namely the behaviour and physiology of The coverage of each subject is clear, less than 800 years is entirely unaccept­ a group of insects seen in the context of accurate and thoughtful. It is not com­ able. If Retallack had spent a little time in their natural environment. Thus, anyone plete, however, and those interested in explaining the process of peat formation, seeking a rounded picture of acoustic particular areas will need to search other including litter formation, detritivore and communication in field crickets would recent references to get the full picture. microbial activity, hydrological inter­ need to quarry in seven different chapters. This problem is most evident in the actions and compaction effects, then it Essentially, what is offered is a com­ behavioural chapters on the calling and would soon become apparent that there prehensive survey of recent research, courtship songs of insects, particularly can be no simple relationship between presented in a way that should make it of crickets and cicadas. But the reference depth and age. There is evidence of a accessible to both graduate students and list provides an up-to-date guide to the degree of oversimplification both here undergraduates. The chapters that top literature, and even expert readers are and elsewhere in his treatment of the and tail the book should be particularly likely to find some entries new to them. interpretation of fossil soils. useful to the beginner. Some aspects of Altogether, then, Ewing's book is a The final section of the book, which is the physics of sound that are relevant to welcome contribution, the more so as it is potentially the most interesting, is the insects are outlined in the first chapter, the first of its kind since Haskell's Insect story of the Earth's history as seen where the main terms are defined. The Sounds a generation ago. A comparison of through the pores of the soil. In fact, the last chapter describes methods for record­ the two books shows how much progress story begins beyond the Earth, on the ing and analysing sound. The illustrations has been made. The breadth of coverage Moon, Venus and Mars, with an account showing the same sound displayed as an that Ewing has been able to maintain is of totally abiotic soils. We are then led oscillogram, a sonagram and a power particularly welcome. Even allowing for through the development of early terres­ spectrum are very helpful for the uniniti­ the present rate of progress, Arthropod trial soils and the impact upon these of the ated, and might have been better at the Bioacoustics should be a valuable source­ rising oxygen levels in the primitive atmos­ start than at the end. book for several years to come. 0 phere. Immediately we hit upon the prob­ In between, there is a catalogue of David Young is in the Department of Zoology, lem of a total lack of modern analogues: research results: the physical mechanisms University of Melbourne, Parkville, Victoria Hartley was right, the past is indeed a of sound production and reception, the 3052, Australia. foreign country. It is difficult, therefore, on the basis of soil evidence, to determine the oxygen component of the Precam­ for the analysis of the yet more complex brian atmosphere. Foreign visit problems of describing and interpreting The development of land vegetation Peter D. Moore fossil soils. provided a new soil-forming factor, and Time is involved at two levels in the some palaeosols, such as coals, are an study of palaeosols: in the initial develop­ important source of information on plant Solis of the Past: An Introduction to ment and maturation of the soil, and in an palaeoecology. But again Retallack fails Paleopedology. By G. J. Retallack. Unwin extended period during which the soil lies to deal adequately with the reconstruction Hyman: 1990. Pp. 520. Hbk £60; pbk in a 'fossil' state. Interpretation of a of conditions in the coal-forming swamps £24.95. palaeosol entails the separation of these (or bogs?) of the Carboniferous. We are two processes. Post-burial diagenesis left with no clear idea of the ecological, THE past, according to novelist L. P. often involves compaction and, at high climatic or hydrological conditions in Hartley, is a foreign country - they do temperature, may even involve meta­ those palaeohabitats where coal ulti­ things differently there. But it is the morphosis of the soil. Cementation and matelyaccumulated. ardent hope of palaeoecologists (a group mineral replacement can take a soil far The greatest strength of this book is in including the palaeopedologists) that they from its original, pre-burial state. Con­ the clarity of its diagrams and Retallack's did things much the same, so that we can fusion of the two times cales is possible, as graphic explanation of soil-forming confidently use the present as a key to the author shows by examples from the processes and soil classification systems. understanding the past. For this reason, Carboniferous and the Permian. Its weakness lies in the author's failure to any book on palaeosols needs to begin Yet some clues to a soil's original relate specific details of soil study to the with a section on modern soils and soil condition remain intact, such as the nature broad process of environmental history. processes before it can adequately discuss of the organisms, or their traces, left The complexity of soil terminology often the soils of the past. Here, Retallack within the palaeosol. From fungi to ter­ seems to contribute to this lack of clarity, provides a graphic description of three mites, and from nematodes to mammals, statements becoming buried and obfus­ classification systems of modern soils - a vast range of biological information cated by jargon. Whether or not things the traditional Australian system, the US lies within the fossil soil and provides were done differently there, visiting the system (with its hierarchical structure and some secure evidence of past climates and soils of the past certainly demands a distinctive language), and the rather conditions. On the basis of such informa­ foreign language. 0 hybrid FAO system. Retallack compares tion it should be possible to reconstruct these in diagrammatic form and, together whole ecosystems of the past from a fossil Peter D. Moore is in the Department of Ecol• with discussions of soil structure and soil­ soil, but here Retallack is disappointingly ogy Division of Biosphere Sciences, King's forming'processes, provides a secure basis brief and superficial, supplying only vague College, Campden Hill Rd, London WB 7AH, UK. 32 NATURE' VOL 345, 3 MAY 1990 © 1990 Nature Publishing Group