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Genetics of forest ecosystems
BOOK REVIEWS
165
and simulation, particularly when models are used as the basis for practical simulation, places a constraint on many of the models described, and neatly avoids the difficult topic of the validation of models against the real world. More important, however, is the intended contrast between mathematical models and laboratory experiments. The author states in his preface that the original intention was for a book with joint authorship in which models of both kinds would be used to illuminate each other. In the event, this book only deals with mathematical models and, although some use is made of published material, the lack of laboratory parallels to the mathematical models reduces the impact of the book. Nevertheless, an impressive range of mathematical models is covered, from predator-prey relationships with and without age structures, through competition and migration models and the statistical mechanics of several trophic levels, to coevolution and territorial behaviour. Many of the models are treated analytically so as to demonstrate their basic properties, but the computer-oriented ecologist will look in vain for any hints on ways of exploring the properties of the models by computer simulation, even where such simulation would be more illuminating than mathematical analysis. Perhaps the author's insistence on the distinction between models and simulations did not let him stray into a development of the subject matter which would have provided some compensation for the lack of the laboratory models. How successful is the book in giving an introduction to mathematical models in ecology? Certainly, the wide range of models included provides an invaluable starting point for many of the necessary developments in ecological theory. Some of the models included in this book are not readily available elsewhere, including the analysis of delays due to development time, the models of migration, the discussion of the effects of the stability of ecosystems on interactions at different trophic levels, the analysis of character displacement, and the models of territorial behaviour. It is, therefore, particularly useful to have them presented in a modestly priced book of this kind. More guidance on the ways in which the properties of the models can be explored by computer simulation would have been welcome. As is usual in books which proclaim on their dust-covers that 'the book will be comprehensible to anyone with a minimal familiarity with mathematical notation', the mathematician's assessment of 'minimal' is very different from that of the ecologist, and anyone seeking this book will need a sound background of mathematics. Indeed, the book illustrates very well the long way there is to go before mathematicians and ecologists will be able to understand each other in a discussion of ecological models. J. N. R. JEFFERS
Stern, Klaus and Roche, Laurence, Genetics of Forest Ecosystems 1974, Chapman & Hall Ltd., London; Springer-Verlag, Berlin, Heidelberg, New York, 330 pp. 70 Figures. Price: £12.25 in United Kingdom.
166
BOOK REVIEWS
This book sets out to survey the principles which govern the genetic basis of population structure of forest communities. Tree species with their prolonged reproductive cycle, and excessive demands on experimental resources, have not been favoured organisms for genetical studies. Thus, the dearth of experimental, genetical data on trees has necessitated that a major part of the message contained in the text is drawn from the more familiar organisms of laboratory genetics. Large sections which set out the tenets of the subject will therefore be familiar ground to the genetically informed, general biologist. The material is set out in six chapters. The core of the material which accounts for over half the book is presented under the titles: adaptive strategies, and forest ecosystems, By adaptive strategies the authors mean the pattern of responses that develop in micro-evolution in response to selection, and among those discussed are: clinical variation, discontinuities, genetic drift, linkage and introgression. The evidence has been comprehensively reviewed and is clearly presented. For those with an emerging interest in quantitative generalisations of population fitness and of stable communities there are several useful introductions to different aspects of the mathematical basis of response and behaviour in model systems. The well known causal mechanisms of adaptive trends, such as climate, soil, competition, disease, mating systems, pollination and seed dispersal are, for some curious reason, discussed in a chapter misleadingly entitled 'Adaptations'. There is also a useful summary of the rather meagre information available on genetic systems in tree species, but some of the general theoretical conclusions on mating systems show evidence of incomplete understanding, and should not be accepted by the general reader without much reserve. The work concludes with a valuable discussion of the interaction of man with forests, of the disruption of stable equilibria of precious tree species by reckless exploitation, and of the conservation of invaluable genetic material in the species of forest trees that are currently in serious danger of extinction. The work, although generally reasonably easy to read, would have benefited from more rigorous editing of the English translation of the first five chapters. The use of words like cyanogenous (p. 99) and minimax (p. 230) jar, and cytologists will certainly want the general reader to know that the diplotene stage of meiosis is not the accepted resting stage (p. 38) of cell division. Nevertheless, the work will be required reading for forest ecologists, forest-tree breeders, and for students on degree courses in forest biology and management. WATKIN WILLIAMS
Grigg, D. B., The Agricultural Systems of the World: An Evolutionary Approach, Cambridge University Press, London, 1974, 358 pp. 48 Tables. 25 Maps. Price in UK: £6.60 (hardback), £2.75 (paperback).
165
and simulation, particularly when models are used as the basis for practical simulation, places a constraint on many of the models described, and neatly avoids the difficult topic of the validation of models against the real world. More important, however, is the intended contrast between mathematical models and laboratory experiments. The author states in his preface that the original intention was for a book with joint authorship in which models of both kinds would be used to illuminate each other. In the event, this book only deals with mathematical models and, although some use is made of published material, the lack of laboratory parallels to the mathematical models reduces the impact of the book. Nevertheless, an impressive range of mathematical models is covered, from predator-prey relationships with and without age structures, through competition and migration models and the statistical mechanics of several trophic levels, to coevolution and territorial behaviour. Many of the models are treated analytically so as to demonstrate their basic properties, but the computer-oriented ecologist will look in vain for any hints on ways of exploring the properties of the models by computer simulation, even where such simulation would be more illuminating than mathematical analysis. Perhaps the author's insistence on the distinction between models and simulations did not let him stray into a development of the subject matter which would have provided some compensation for the lack of the laboratory models. How successful is the book in giving an introduction to mathematical models in ecology? Certainly, the wide range of models included provides an invaluable starting point for many of the necessary developments in ecological theory. Some of the models included in this book are not readily available elsewhere, including the analysis of delays due to development time, the models of migration, the discussion of the effects of the stability of ecosystems on interactions at different trophic levels, the analysis of character displacement, and the models of territorial behaviour. It is, therefore, particularly useful to have them presented in a modestly priced book of this kind. More guidance on the ways in which the properties of the models can be explored by computer simulation would have been welcome. As is usual in books which proclaim on their dust-covers that 'the book will be comprehensible to anyone with a minimal familiarity with mathematical notation', the mathematician's assessment of 'minimal' is very different from that of the ecologist, and anyone seeking this book will need a sound background of mathematics. Indeed, the book illustrates very well the long way there is to go before mathematicians and ecologists will be able to understand each other in a discussion of ecological models. J. N. R. JEFFERS
Stern, Klaus and Roche, Laurence, Genetics of Forest Ecosystems 1974, Chapman & Hall Ltd., London; Springer-Verlag, Berlin, Heidelberg, New York, 330 pp. 70 Figures. Price: £12.25 in United Kingdom.
166
BOOK REVIEWS
This book sets out to survey the principles which govern the genetic basis of population structure of forest communities. Tree species with their prolonged reproductive cycle, and excessive demands on experimental resources, have not been favoured organisms for genetical studies. Thus, the dearth of experimental, genetical data on trees has necessitated that a major part of the message contained in the text is drawn from the more familiar organisms of laboratory genetics. Large sections which set out the tenets of the subject will therefore be familiar ground to the genetically informed, general biologist. The material is set out in six chapters. The core of the material which accounts for over half the book is presented under the titles: adaptive strategies, and forest ecosystems, By adaptive strategies the authors mean the pattern of responses that develop in micro-evolution in response to selection, and among those discussed are: clinical variation, discontinuities, genetic drift, linkage and introgression. The evidence has been comprehensively reviewed and is clearly presented. For those with an emerging interest in quantitative generalisations of population fitness and of stable communities there are several useful introductions to different aspects of the mathematical basis of response and behaviour in model systems. The well known causal mechanisms of adaptive trends, such as climate, soil, competition, disease, mating systems, pollination and seed dispersal are, for some curious reason, discussed in a chapter misleadingly entitled 'Adaptations'. There is also a useful summary of the rather meagre information available on genetic systems in tree species, but some of the general theoretical conclusions on mating systems show evidence of incomplete understanding, and should not be accepted by the general reader without much reserve. The work concludes with a valuable discussion of the interaction of man with forests, of the disruption of stable equilibria of precious tree species by reckless exploitation, and of the conservation of invaluable genetic material in the species of forest trees that are currently in serious danger of extinction. The work, although generally reasonably easy to read, would have benefited from more rigorous editing of the English translation of the first five chapters. The use of words like cyanogenous (p. 99) and minimax (p. 230) jar, and cytologists will certainly want the general reader to know that the diplotene stage of meiosis is not the accepted resting stage (p. 38) of cell division. Nevertheless, the work will be required reading for forest ecologists, forest-tree breeders, and for students on degree courses in forest biology and management. WATKIN WILLIAMS
Grigg, D. B., The Agricultural Systems of the World: An Evolutionary Approach, Cambridge University Press, London, 1974, 358 pp. 48 Tables. 25 Maps. Price in UK: £6.60 (hardback), £2.75 (paperback).