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TREE vol. 4, no. 70, October 1989

_-- ---._._--_--.-. Modern Systematics

Prospects in Systematics

edited by D.L. Hawksworth, Oxford University Press (Syst. Assoc. Spec. Vol. 36), 1988. f#5.00/$98.00 hbk (xx + 457 pages) ISBN 0 19 857707 9

Prospects in Systematics is spon- sored by the Systematics Associ- ation to mark its golden jubilee. It offers a critical review of achieve- ments and developments in sys- tematics over the last 50 years, and more particularly since the publi- cation in 1940 of the Association’s seminal work, The New System- atics’. Systematics has witnessed unparalleled activity since the publi- cation of Huxley’s book. Prospects in Systematics readdresses basic questions about the relevance of systematics, the role it should play into the next century, and the major challenges it now faces.

The book contains 25 chapters or- ganized in six sections. Most of the authors are based in Britain. In the introductory section, Hawksworth and Bisby present a synopsis of the contribution of the Association and an assessment of the state of sys- tematics, its products, user require- ments, and the constraints to its development. Mayr reviews recent progress. Heywood reviews the structure of systematics itself.

In the next section, on systematics and evolution, Patterson critically analyses new evolutionary theories and their impact. Claridge empha- sizes the situation at and below the species level, with particular refer- ence to concepts of allopatry and sympatry. Felsenstein focuses on techniques for the detection of phy- logeny. Hallam stresses the con- tinuing relevance of paleontology in contemporary systematics and evolutionary studies.

The third section discusses the im- plication of modern methods. Dover, Young and Fergusson separately re- flect on the implications for system- atics of recent advances in genetics, molecular biology and biochemistry. Joysey cautions against simplistic approaches to systematics, as do Duckett and Gower for ultrastruc- tural and numerical approaches re- spectively. Phenetic and cladistic approaches are compared by Sneath, who emphasizes the need to question what a particular classifi- cation is for.

In the section on taxonomic infor- mation systems, Bisby stresses the importance of communication with users, while Watson et al. demon- strate what has already been achieved. Clarke and Alkin, in separ- ate chapters, look at the ways in

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which bibliographic data bases and taxonomically intelligent data bases might develop in future. Ride con- siders how codes governing the basal taxonomic information, scien- tific names, need to evolve to accommodate modern users’ re- quirements.

In the fifth section, on applications, Nolan discusses the use of names in microbiology. Pickersgill, and Muller and Baker, illustrate the relevance of systematics at the species level to diverse aspects of applied biology.

In the final section, on prospects for the next century, Haskel and Mor- gan review user needs and obstacles to their fulfilment, and make pro- posals for the future organization of the subject. Berry stresses the need for an increased level of understand- ing of the variety of life in the edu- cation of biologists. Margulis shows how the number of kingdoms of liv- ing organisms must be expanded to accommodate the endosymbiotic theory of the evolution of eukaryote

cells and the wealth of new data with systematic relevance.

A minor criticism of the book is that biogeography, the sister disci- pline of systematics, is mentioned only in passing. A chapter on the relationships between systematics and biogeography, with special ref- erence to the power of phylogenetic studies as applied to historical bio- geography, would have been useful.

Reading this volume, one cannot help but feel that systematics is one of the most indispensable, active, and rewarding branches of biology. Prospects in Sysrematics is an important contribution that will benefit advanced students and pro- fessionals alike.

Jorge V. Crisci

Museo de La Plats, 1900 La Plats, Argentina

Reference 1 Huxley, J.S., ed. (1940) The New Systematics, Oxford University Press

-An Introduction to Modeling

Dynamic Modeling in Behavioral Ecology

by Marc Mangel and Colin W. Clark, Princeton University Press (Mono- graphs in Behavior and Ecology Series), 1988. $45.00 hbk, $15.95 pbk (xii + 308 pages) ISBN 0 697 08506 4

The last two decades have seen a huge growth in the number of opti- mization models in behavioral ecol- ogy. Initially, most models looked at restricted situations where it was reasonable to assume that maxi- mization of fitness was equivalent to maximization of some simple cur- rency such as the mean net rate of energetic gain. The authors of this book have been two of the main propagandists for the use of dy- namic models. These models look at sequences of behavior over time, and attempt to link present actions to

future life history, so that the cur- rency maximized is fitness itself. Such models are enormously more powerful than the old simple models. They are able to take the animal’s state into account, and be- cause fitness provides a common currency, are able to compare the benefits of different types of action.

This book describes how to con- struct dynamic models, and illus- trates their use by a number of examples. The book is divided into three parts.

Part I describes the technical details of dynamic programming. These are taught through an example in which an animal can choose between different patches of food. A ‘hands on’ approach by the reader is definitely called for here. The authors’ philosophy seems to be that to learn how to build dynamic models you have to do it yourself. Thus, to do justice to this book one really needs to spend much time and effort working on examples. This is especially true for Part I, but some- thing of this approach still applies to Part II, where supplementary exer- cises are occasionally suggested. If one is prepared to put in the required effort then there is a wealth of wis- dom and experience here, with many hints and much technical advice. This makes the book excellent for gradu- ate students.

In addition to the basic patch- choice model, appendices provide

TREE vol. 4, no. 10, October 1989

elaborations that will be useful to specialists involved in dynamic modeling. Also included in this first part of the book is a section giving a clear introduction to probability, and even an addendum showing how to write a computer program in Basic! Everything one needs is here, but for some of the more tersely covered peripheral topics it might be better to read elsewhere.

Part II of the book is more access- ible to the casual reader. Each of the five chapters deals with a differ- ent biological problem. Apart from requiring a basic knowledge of dy- namic programming, each is self- contained. The structure of the chap- ters exemplifies a good modeling approach. Chapters start with a dis- cussion of the biology, which leads to the construction of a simple model with clearly recognized assumptions and limitations. Finally, having gained insight from simple models, one may proceed to more sophisti- cated models.

Sometimes the numerical solution of a model tells one little beyond the simple qualitative insights already gained. Mangel and Clark are aware of this but emphasize that a state variable approach must be closely tied to the underlying biology and requires one to be explicit about details. They argue that the thought processes required to construct a model help to clarify ideas and in

themselves lead to new insights. Their examples certainly illustrate this point.

The wide range of biological prob- lems covered in these five chapters demonstrates the enormous power of the dynamic modeling approach, and illustrates that it is a natural approach in a host of situations. Of course, there are dangers in this uni- versality. Just because dynamic modeling can be used almost every- where does not mean that it should be used when simpler models will do. Mangel and Clark are well aware of such pitfalls, but I suspect that not all those who use dynamic modeling in the future will be so aware.

The third part is essentially a series of appendices on a variety of topics. The depth of coverage and value of these pieces are very variable. Amongst the gems is a section on optimization models. Modeling is an art at which Mangel and Clark are masters, and this section gives valu- able advice on the philosophy of model construction and on good and bad ways to construct a model. Other topics, however, receive only brief attention. For example the sec- tion on mean-variance models starts by describing the Z-scores model. As the authors say, this is a non- dynamic model in which there is only a single choice period, and one should use dynamic programming to obtain optimal sequential policies.

They then pass on to other matters, ignoring the literature that does treat the problem dynamically1-3. Another glaring omission occurs in the sec- tion on learning. This section de- scribes the problem of learning about and exploiting unknown patches of food, and yet omits men- tion of the seminal work of Krebs, Kacelnik and Taylor4.

The final topic is dynamic be- havioral games, an area that is fraught with computational and con- ceptual complexities. Nevertheless, it is extremely important biologi- cally, and I expect to see an ex- plosion in the number of papers that deal with it. Mangel and Clark dis- cuss the area in some depth, and its inclusion is most welcome.

A knowledge of dynamic modeling is essential for anyone seriously in- terested in behavioral ecology, and this book provides a comprehensive introduction to the subject.

John McNamara School of Mathematics, University of Bristol, University

Walk, Bristol BS8 lTW, UK

References 1 McNamara, J.M. (1983) Math. Oper. Res. 8,373-380 2 McNamara, J.M. (1984) S/AM J. ConWol 22,87-94 3 McNamara, J.M. and Houston, A.I. (1986) Am. Nat. 127,358-378 4 Krebs, J.R., Kacelnik, A. and Taylor, P. (1978) Nature 275,27-31

Unpredictability

Protean Behaviour

by P.M. Driver and D.A. Humphries, Oxford University Press, 7988. I f30.00 hbk (324 pages) ISBN 0 19 857770 4

Ay, Proteus, but that life is alter’d now.

The Two Gentlemen of Verona, Act IV, Scene ii.

The term ‘protean behaviour’ is de- rived from the mythical figure Pro- teus, who was able to confuse his enemies by changing his shape. It was introduced by Chance and Russell’ and is defined by Driver and Humphries as ‘that behaviour which is sufficiently unsystematic in appearance to prevent a reactor predicting in detail the position or actions of the actor’.

The book begins with a chapter that introduces some examples of protean phenomena. These include the erratic ‘jinking’ of a rabbit that is pursued by a predator, the mobbing

of a predator by small birds, the injury-feigning anti-predator be- haviour of birds and the convulsive anti-predator behaviour of moths and mice. There follows a chapter in which the authors discuss the con- cept of unpredictability and outline their approach, which is basically darwinian, in that protean behaviour is explained by the evolutionary advantages that it confers.

Chapter 3 (‘Strategies and Tactics’) starts with a defence of the transfer of terms like ‘strategy’ and ‘tactics’ from human behaviour to features of animals such as their colouration. This is immediately followed by an attack on the use of ‘selfish’ in the context of genes. Such a juxtaposi- tion suggests a lack of consistency. It also indicates a lack of awareness of the considerable discussion about ‘selfish’ genes that has taken place. Perhaps more seriously, the authors do not seem to realise that ‘selfish’ genes form the basis of the concept of an evolutionary stable strategy (ESS) that they mention with approv-

al on p.15. The discussion of selfish genes is part of an unsatisfactory treatment of the ‘levels of selection’ argument. I was surprised that the authors see the gene selection ver- sus group selection argument as reminiscent of the instinct versus learning dispute. They imply that their concentration on the whole organism is a sensible alternative to the extremes of either gene selection or group selection. But either gene selection or group selection can be used to make predictions about indi- viduals, so concentrating on indi- viduals does nothing to resolve the conflict between genes and groups as levels of selection.

Their advocacy of a study of whole organisms leads Driver and Hum- phries to a list of animal interactions in which protean principles can ap- ply, comprising competition, part- nership, predation and parasitism. They concentrate on predator-prey interactions, and the next four chap- ters contain a detailed account of protean behaviour in this context.

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