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Textbook evolution
BOOK REVIEWS
A plant point of view Alpine Plant Life: Functional Plant Ecology of High Mountain Ecosystems by C. Körner Springer-Verlag, 1999. £37.50/$64.95 pbk (ix 1 343 pages) ISBN 3 540 65438 0
A
lpine plants hold a fascination for many people, as a browse through the gardening section of your local bookshop will no doubt attest. In the preface to this book, Körner acknowledges such fascination for plants as a stimulus for his own early interest in botany and biology. However, where gardening books and most previous texts dealing with the ecology of alpine vegetation are of a mainly descriptive nature, Alpine Plant Life presents a clear, often quantitative exploration of the interactions between plants and the spectrum of physical conditions they encounter in high mountain environments. The book is a new and innovative contribution to alpine ecology. Although the interface between vegetation and the physical environment has been well researched under field and laboratory conditions in a wide variety of habitats, and is to be regarded as part of classic plant ecology, Körner’s approach is refreshing in its concentration upon the plant point of view. For example, on the first page of Chapter 1 the reader is reminded that conditions usually regarded by us as harsh might not be so for plants, and indeed might not even be experienced at the microlevel of the individual plant or leaf. Similarly, the differences for plants between high mountain (alpine) and high latitude (tundra) environments are highlighted at an early stage. This is a welcome change from the traditional, and misleading, tendency to treat these two types of environment as broadly similar, merely because they are both cold. Although there is no formal division of chapters into thematic sections, the author defines the tone of the book in Chapters 1–3 by outlining the general physical constraints on life in high mountains, and by providing a geographical and historical overview of research, with accounts of the alpine life zone and alpine climates. Serious consideration of the plant viewpoint begins in Chapter 4 – ‘The climate plants experience’. From here, we are led through accounts of life under snow, the formation and structure of alpine soils, and the intricacies of treelines, to a series of chapters dealing with plant stress factors and resources, including solar radiation, water, minerals and carbon. Subsequent chapters
342
include discussions of plant growth dynamics, cell division and tissue formation, biomass production, reproduction and finally global change at high altitudes. Although the order of presentation of topics might lose its logical thread in some places, this is made up for by the breadth of coverage of the subject matter. The synthesis of evidence and ideas provides a new insight as to how the variety of sizes, growth forms, rooting systems, flowers and physiological peculiarities of alpine plants evolved. In discussing many of his topics, Körner strikes a useful balance between consideration of the roles of plants in cycling substances through mountain ecosystems and description of the plant physiological processes involved. Just as impressive is the integration of general information to enable elaboration of the intricacies of the more specialized situation in mountain systems. The success of this strategy is particularly apparent in the chapters dealing with water relations and climatic stress from solar radiation, but is also to be found throughout the book. My single major criticism of the work is that in the end, the reader is presented with only half of the story. In spite of the allencompassing title, this book is not a useful source of reference if you wish to know about organism interactions involving plants in mountain ecosystems. Plant competition, population and community dynamics, succession and plant–animal interactions are all untouched. Token accounts of the roles of microbes and mycorryhiza, and of animals as pollinators or herbivores, do little to inform the reader in these directions. The deficit is partly a consequence of insufficient alpine research worldwide, but it also reflects the author’s own focus of interests and expertise in the physical aspects of alpine plant ecology. The situation reaches an extreme in the final short chapter on ‘Global change at high elevation’. I remain unconvinced that it is helpful to write a chapter on plants and environmental change on mountains (or, indeed, anywhere else) without ever mentioning succession – a process, by definition, synonymous with organism, particularly vegetational, reactions to environmental disturbance in the widest sense1. Other criticisms of the book are minor. A few more examples taken from the Australian region would have helped the geographical balance. I also found the highlighting of certain words, phrases and passages inappropriate in places. These accents are not explained and, for me, only occasionally reflect the key issues at hand. However, none of this detracts from my overall positive impression of the book; it is a welcome contribution to an important area of modern ecology that is often neglected. The book should be readily
0169-5347/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved.
available to anyone who professes to have a scientific interest in mountain biology. I enjoyed the read, not least because I completed this review while sitting at about 2400 m on an Austrian Alp, with all the reference material I needed at my feet.
John R. Haslett Institute of Zoology, University of Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria ([email protected])
References 1 Bazzaz, F.A. (1996) Plants in Changing Environments: Linking Physiological, Population and Community Ecology, Cambridge University Press
Textbook evolution Evolution: An Introduction by S.C. Stearns and R.F. Hoekstra Oxford University Press, 1999. £18.99 hbk (394 pages) ISBN 0 19 854968 7
T
o many students the term ‘textbook’ conjures up visions of a weighty tome conveying, in a ponderous manner, an authoritative, worthy, but ultimately outdated and dull account of the subject in question. Evolution: An Introduction is a conscious attempt to break out of this straightjacket, and provide students with a racy and contemporary account of evolutionary biology – one that they might be tempted to read from cover-to-cover over the duration of an introductory course. The devices used to produce such a studentfriendly textbook are familiar; copious illustrations, minimal mathematical content, a prologue worthy of a David Attenborough script, and an assurance to the student that, although necessarily limited in scope, the book contains what is essential and exciting in evolution. So much for the presentation, what about the content? To borrow a footballing cliché, this is very much a book of two halves. The last eleven chapters of the book are well written, informative, and cover exciting and actively developing areas in evolutionary biology, using new examples for illustration. Topics such as the uniqueness of evolution, cladistics, phylogenetic constraints and the importance of history in evolution all come across strongly. The excitement and application of recent discoveries in developmental genetics, and the power of new molecular tools to open up previously TREE vol. 15, no. 8 August 2000
BOOK REVIEWS intractable areas, are admirably conveyed to the reader. In stark contrast, I found sections of the first six chapters, covering such fundamental topics as population, ecological and quantitative genetics, to be disappointing, irritating and confusing. My disappointment stems from the inability of the authors either to make adequate concessions for the background knowledge of their audience or to organize the material in a logical and progressive fashion. This means that unnecessarily technical terms are often used in early chapters without adequate definition or explanation, undoubtedly hindering student understanding and their ability to read the book straight through. The lack of a logical structure to these chapters also means that crucial concepts, such as the link between single locus variation and quantitative phenotypic variation, and the process and consequences of genetic drift, get lost amid a plethora of less important topics. The main source of my irritation arises from the timidity of the authors in adopting an almost wholly qualitative approach to the subject, shying away from all but the most basic mathematical treatment of evolutionary issues. Quantitative analysis of evolutionary processes, the development of quantitative models, and the testing of these quantitative models are such an integral and stimulating aspect of evolutionary studies that those students who can deal with them should be catered for. Even where mathematical models have been introduced, the tables used to illustrate calculations of gene frequency change are poorly laid out, and associated graphs lack information on model parameter values, thus making interpretation impossible. However, my most serious reservation about this section of the book arises from what I consider to be a perverse decision on the part of the authors to redefine the term natural selection and make it synonymous with phenotypic selection, the association of phenotypic value with fitness. The concept of natural selection is so fundamental to an understanding of evolution, and has been so widely misrepresented, that introducing a redefinition that contradicts accepted usage seems a certain recipe for disaster. To compound this particular confusion, a variety of inconsistent definitions of natural selection actually appear in this book. Thus, natural selection is variously ‘the correlation of reproductive success with a trait’, ‘a non-zero correlation of reproductive success with a trait or gene’ and ‘variation in reproductive success’. As an antidote to this confusion, can I recommend the scholarly discussion and definition of natural selection to be found in Endler1. Would I include this book on my students’ reading list? On the basis of the conTREE vol. 15, no. 8 August 2000
tent of the last 11 chapters my answer would be yes. However, I am not about to redefine natural selection according to Stearns and Hoekstra (2000), and I would certainly suggest alternative texts to introduce the fundamentals of population, quantitative and ecological genetics.
Richard A. Ennos IERM, University of Edinburgh, Mayfield Road, Edinburgh, UK EH9 3JU ([email protected])
References 1 Endler, J.A. (1986) Natural Selection in the Wild, Princeton
Take the best Simple Heuristics that Make us Smart by G. Gigerenzer, P.M. Todd and the ABC Research Group Oxford University Press, 1999. £24.95/$35.00 hbk (xv 1 416 pages) ISBN 0 19 512156 2
R
obert Axelrod became famous when he investigated various strategies in the repeated Prisonner’s Dilemma game and found that a simple one - ‘tit for tat’ turned out to be the best competing strategy1. The Evolution of Cooperation1 stimulated a wealth of research and today we know that tit for tat is by no means unbeatable2,3. A similarly well formulated and thought provoking book has now been written in cognitive psychology, with clear relevance for evolutionary psychology and behavioural ecology, as well as for economics and artificial intelligence research. The main focus is on cognitive mechanisms that are fast and frugal for making decisions. Fast means that they do not involve much computation and frugal means that they only search for some of the available information. The impressing result is that they show that simple rules of thumb, such as the heuristic ‘take the best’, can be quite accurate, and in many instances can beat more sophisticated models for cognitive performance in computer simulations. Simple Heuristics that Make us Smart is about how fast and frugal heuristics for making decisions work, and when and why they succeed. These heuristics can be seen as models of behaviour in both living and artificial systems; they are intended to capture how real minds make decisions under constraints of limited time and knowledge, and to suggest ways to build artificially intelligent systems.
To understand the thesis of Simple Heuristics that Make us Smart, you have to understand the position against which the authors argue: reasoning that requires unlimited time and knowledge. They describe two such approaches: unbounded rationality (decision making strategies that have little, or no, regard for the constraints of time, knowledge and computational capacities that real humans and animals face, which is traditionally modelled by probability theory) and optimization under constraints (which acknowledges that search must be limited, but which has an unrealistic and computationally demanding rule for deciding when to stop looking for more information). It is argued, and shown, that reasoning can be powerful and accurate without requiring unlimited time and knowledge, by means of two boundedrationality approaches: satisficing, and fast and frugal heuristics. Satisficing is a method for making a choice from a set of sequentially encountered alternatives (when one does not know much about the possibilities ahead of time), setting an adjustable aspiration level and ending the search for alternatives as soon as one is encountered that exceeds the aspiration level. Fast and frugal heuristics employs minimum time, knowledge and computation to make adaptive choices in real environments. The book and the research it presents were made possible by a unique funding policy of the Max Planck Society in Germany. The two main authors (Gigerenzer and Todd) were allowed to take on a challenging project with an uncertain outcome by adopting a research perspective over many years. In 1995, they brought together 16 scientists from several disciplines relevant for their task (psychology, mathematics, computer science, economics and evolutionary biology). The group’s name, the ABC research group, is short for the Center for Adaptive Behavior and Cognition, but it also refers to the study of the ABCs of decision making heuristics – the basic building blocks from which these inference mechanisms are made. After three years of hard and stimulating work, they invite the rest of the academic world to take part in their impressive journey into a largely unknown territory. The book consists of 16 chapters, which are all multiauthored, reflecting the interdisciplinary collaboration among the researchers. The text flows smoothly, as though it were written by a single author. It is well edited with cross-references between the chapters, and most chapters can be read independently of the others. It is a delight to read, reflecting clear minds and an innovative research programme. The writing of the book stopped in mid 1998, thus their website (http://www. mpib-berlin. mpg.de/abc/) is now the place to continue your ABCs.
0169-5347/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved.
343
A plant point of view Alpine Plant Life: Functional Plant Ecology of High Mountain Ecosystems by C. Körner Springer-Verlag, 1999. £37.50/$64.95 pbk (ix 1 343 pages) ISBN 3 540 65438 0
A
lpine plants hold a fascination for many people, as a browse through the gardening section of your local bookshop will no doubt attest. In the preface to this book, Körner acknowledges such fascination for plants as a stimulus for his own early interest in botany and biology. However, where gardening books and most previous texts dealing with the ecology of alpine vegetation are of a mainly descriptive nature, Alpine Plant Life presents a clear, often quantitative exploration of the interactions between plants and the spectrum of physical conditions they encounter in high mountain environments. The book is a new and innovative contribution to alpine ecology. Although the interface between vegetation and the physical environment has been well researched under field and laboratory conditions in a wide variety of habitats, and is to be regarded as part of classic plant ecology, Körner’s approach is refreshing in its concentration upon the plant point of view. For example, on the first page of Chapter 1 the reader is reminded that conditions usually regarded by us as harsh might not be so for plants, and indeed might not even be experienced at the microlevel of the individual plant or leaf. Similarly, the differences for plants between high mountain (alpine) and high latitude (tundra) environments are highlighted at an early stage. This is a welcome change from the traditional, and misleading, tendency to treat these two types of environment as broadly similar, merely because they are both cold. Although there is no formal division of chapters into thematic sections, the author defines the tone of the book in Chapters 1–3 by outlining the general physical constraints on life in high mountains, and by providing a geographical and historical overview of research, with accounts of the alpine life zone and alpine climates. Serious consideration of the plant viewpoint begins in Chapter 4 – ‘The climate plants experience’. From here, we are led through accounts of life under snow, the formation and structure of alpine soils, and the intricacies of treelines, to a series of chapters dealing with plant stress factors and resources, including solar radiation, water, minerals and carbon. Subsequent chapters
342
include discussions of plant growth dynamics, cell division and tissue formation, biomass production, reproduction and finally global change at high altitudes. Although the order of presentation of topics might lose its logical thread in some places, this is made up for by the breadth of coverage of the subject matter. The synthesis of evidence and ideas provides a new insight as to how the variety of sizes, growth forms, rooting systems, flowers and physiological peculiarities of alpine plants evolved. In discussing many of his topics, Körner strikes a useful balance between consideration of the roles of plants in cycling substances through mountain ecosystems and description of the plant physiological processes involved. Just as impressive is the integration of general information to enable elaboration of the intricacies of the more specialized situation in mountain systems. The success of this strategy is particularly apparent in the chapters dealing with water relations and climatic stress from solar radiation, but is also to be found throughout the book. My single major criticism of the work is that in the end, the reader is presented with only half of the story. In spite of the allencompassing title, this book is not a useful source of reference if you wish to know about organism interactions involving plants in mountain ecosystems. Plant competition, population and community dynamics, succession and plant–animal interactions are all untouched. Token accounts of the roles of microbes and mycorryhiza, and of animals as pollinators or herbivores, do little to inform the reader in these directions. The deficit is partly a consequence of insufficient alpine research worldwide, but it also reflects the author’s own focus of interests and expertise in the physical aspects of alpine plant ecology. The situation reaches an extreme in the final short chapter on ‘Global change at high elevation’. I remain unconvinced that it is helpful to write a chapter on plants and environmental change on mountains (or, indeed, anywhere else) without ever mentioning succession – a process, by definition, synonymous with organism, particularly vegetational, reactions to environmental disturbance in the widest sense1. Other criticisms of the book are minor. A few more examples taken from the Australian region would have helped the geographical balance. I also found the highlighting of certain words, phrases and passages inappropriate in places. These accents are not explained and, for me, only occasionally reflect the key issues at hand. However, none of this detracts from my overall positive impression of the book; it is a welcome contribution to an important area of modern ecology that is often neglected. The book should be readily
0169-5347/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved.
available to anyone who professes to have a scientific interest in mountain biology. I enjoyed the read, not least because I completed this review while sitting at about 2400 m on an Austrian Alp, with all the reference material I needed at my feet.
John R. Haslett Institute of Zoology, University of Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria ([email protected])
References 1 Bazzaz, F.A. (1996) Plants in Changing Environments: Linking Physiological, Population and Community Ecology, Cambridge University Press
Textbook evolution Evolution: An Introduction by S.C. Stearns and R.F. Hoekstra Oxford University Press, 1999. £18.99 hbk (394 pages) ISBN 0 19 854968 7
T
o many students the term ‘textbook’ conjures up visions of a weighty tome conveying, in a ponderous manner, an authoritative, worthy, but ultimately outdated and dull account of the subject in question. Evolution: An Introduction is a conscious attempt to break out of this straightjacket, and provide students with a racy and contemporary account of evolutionary biology – one that they might be tempted to read from cover-to-cover over the duration of an introductory course. The devices used to produce such a studentfriendly textbook are familiar; copious illustrations, minimal mathematical content, a prologue worthy of a David Attenborough script, and an assurance to the student that, although necessarily limited in scope, the book contains what is essential and exciting in evolution. So much for the presentation, what about the content? To borrow a footballing cliché, this is very much a book of two halves. The last eleven chapters of the book are well written, informative, and cover exciting and actively developing areas in evolutionary biology, using new examples for illustration. Topics such as the uniqueness of evolution, cladistics, phylogenetic constraints and the importance of history in evolution all come across strongly. The excitement and application of recent discoveries in developmental genetics, and the power of new molecular tools to open up previously TREE vol. 15, no. 8 August 2000
BOOK REVIEWS intractable areas, are admirably conveyed to the reader. In stark contrast, I found sections of the first six chapters, covering such fundamental topics as population, ecological and quantitative genetics, to be disappointing, irritating and confusing. My disappointment stems from the inability of the authors either to make adequate concessions for the background knowledge of their audience or to organize the material in a logical and progressive fashion. This means that unnecessarily technical terms are often used in early chapters without adequate definition or explanation, undoubtedly hindering student understanding and their ability to read the book straight through. The lack of a logical structure to these chapters also means that crucial concepts, such as the link between single locus variation and quantitative phenotypic variation, and the process and consequences of genetic drift, get lost amid a plethora of less important topics. The main source of my irritation arises from the timidity of the authors in adopting an almost wholly qualitative approach to the subject, shying away from all but the most basic mathematical treatment of evolutionary issues. Quantitative analysis of evolutionary processes, the development of quantitative models, and the testing of these quantitative models are such an integral and stimulating aspect of evolutionary studies that those students who can deal with them should be catered for. Even where mathematical models have been introduced, the tables used to illustrate calculations of gene frequency change are poorly laid out, and associated graphs lack information on model parameter values, thus making interpretation impossible. However, my most serious reservation about this section of the book arises from what I consider to be a perverse decision on the part of the authors to redefine the term natural selection and make it synonymous with phenotypic selection, the association of phenotypic value with fitness. The concept of natural selection is so fundamental to an understanding of evolution, and has been so widely misrepresented, that introducing a redefinition that contradicts accepted usage seems a certain recipe for disaster. To compound this particular confusion, a variety of inconsistent definitions of natural selection actually appear in this book. Thus, natural selection is variously ‘the correlation of reproductive success with a trait’, ‘a non-zero correlation of reproductive success with a trait or gene’ and ‘variation in reproductive success’. As an antidote to this confusion, can I recommend the scholarly discussion and definition of natural selection to be found in Endler1. Would I include this book on my students’ reading list? On the basis of the conTREE vol. 15, no. 8 August 2000
tent of the last 11 chapters my answer would be yes. However, I am not about to redefine natural selection according to Stearns and Hoekstra (2000), and I would certainly suggest alternative texts to introduce the fundamentals of population, quantitative and ecological genetics.
Richard A. Ennos IERM, University of Edinburgh, Mayfield Road, Edinburgh, UK EH9 3JU ([email protected])
References 1 Endler, J.A. (1986) Natural Selection in the Wild, Princeton
Take the best Simple Heuristics that Make us Smart by G. Gigerenzer, P.M. Todd and the ABC Research Group Oxford University Press, 1999. £24.95/$35.00 hbk (xv 1 416 pages) ISBN 0 19 512156 2
R
obert Axelrod became famous when he investigated various strategies in the repeated Prisonner’s Dilemma game and found that a simple one - ‘tit for tat’ turned out to be the best competing strategy1. The Evolution of Cooperation1 stimulated a wealth of research and today we know that tit for tat is by no means unbeatable2,3. A similarly well formulated and thought provoking book has now been written in cognitive psychology, with clear relevance for evolutionary psychology and behavioural ecology, as well as for economics and artificial intelligence research. The main focus is on cognitive mechanisms that are fast and frugal for making decisions. Fast means that they do not involve much computation and frugal means that they only search for some of the available information. The impressing result is that they show that simple rules of thumb, such as the heuristic ‘take the best’, can be quite accurate, and in many instances can beat more sophisticated models for cognitive performance in computer simulations. Simple Heuristics that Make us Smart is about how fast and frugal heuristics for making decisions work, and when and why they succeed. These heuristics can be seen as models of behaviour in both living and artificial systems; they are intended to capture how real minds make decisions under constraints of limited time and knowledge, and to suggest ways to build artificially intelligent systems.
To understand the thesis of Simple Heuristics that Make us Smart, you have to understand the position against which the authors argue: reasoning that requires unlimited time and knowledge. They describe two such approaches: unbounded rationality (decision making strategies that have little, or no, regard for the constraints of time, knowledge and computational capacities that real humans and animals face, which is traditionally modelled by probability theory) and optimization under constraints (which acknowledges that search must be limited, but which has an unrealistic and computationally demanding rule for deciding when to stop looking for more information). It is argued, and shown, that reasoning can be powerful and accurate without requiring unlimited time and knowledge, by means of two boundedrationality approaches: satisficing, and fast and frugal heuristics. Satisficing is a method for making a choice from a set of sequentially encountered alternatives (when one does not know much about the possibilities ahead of time), setting an adjustable aspiration level and ending the search for alternatives as soon as one is encountered that exceeds the aspiration level. Fast and frugal heuristics employs minimum time, knowledge and computation to make adaptive choices in real environments. The book and the research it presents were made possible by a unique funding policy of the Max Planck Society in Germany. The two main authors (Gigerenzer and Todd) were allowed to take on a challenging project with an uncertain outcome by adopting a research perspective over many years. In 1995, they brought together 16 scientists from several disciplines relevant for their task (psychology, mathematics, computer science, economics and evolutionary biology). The group’s name, the ABC research group, is short for the Center for Adaptive Behavior and Cognition, but it also refers to the study of the ABCs of decision making heuristics – the basic building blocks from which these inference mechanisms are made. After three years of hard and stimulating work, they invite the rest of the academic world to take part in their impressive journey into a largely unknown territory. The book consists of 16 chapters, which are all multiauthored, reflecting the interdisciplinary collaboration among the researchers. The text flows smoothly, as though it were written by a single author. It is well edited with cross-references between the chapters, and most chapters can be read independently of the others. It is a delight to read, reflecting clear minds and an innovative research programme. The writing of the book stopped in mid 1998, thus their website (http://www. mpib-berlin. mpg.de/abc/) is now the place to continue your ABCs.
0169-5347/00/$ – see front matter © 2000 Elsevier Science Ltd. All rights reserved.
343