TREE vol. 4, no. 3, March 1989

the fitness of the organism is not altered by their presence or absence; and so they play no major role in evolution. They are junk sequences maintained as either parasitic or ignorant DNA due to the biochemical machinery of genome replication. They also argue that the relative pos- ition of genes in the genome may not be as important as was once thought and that there is no evidence for large developmental domains.

The fourth chapter considers the relationship between genomic and evolutionary change and concludes that ‘there is no simple, consistent or meaningful relationship between these genomic changes and the prin- cipal evolutionary events that have occurred within eukaryotes’. This is based on a wealth of data, the most compelling being the hybrid be- tween the Indian muntjac (n=3) and the Chinese muntjac (n=23). In spite of this difference in chromosome number ‘the developmental circuits

are, in all essentials, identical within these two species’.

The final two chapters discuss and summarize what the authors call the unsolved problem: the origin of mor- phological novelty. Here I found them a little uncertain. Having dis- missed the more conventional types of genetic variation they return to a discussion of interacting gene cir- cuits, and propose alterations in (a) the timing of developmental events, (b) binary switch mechanisms and (c) cell interactions as being of para- mount importance. While I would not disagree with this view, it is somewhat contradicted in a chapter which claims that ‘the appeals so far made to altered gene regulation as a basis for morphological novelty have been unhelpful and largely semantic’.

However, I find this a powerful and thought-provoking book based on extensive scholarship. Let it be said also, for fear of falling into pan-

egyric, that I found the writing un- even and some arguments less well expressed than others. There were also minor errors.

But do read this book. If you are interested in evolution you will sure- ly want to find out what led two scholars to write ‘The neo-Darwinian approach to the analysis of evolution is based on a mathematics which reduces the entire process to the study of changes in gene frequencies within populations, assuming that such changes can, by extrapolation, eventually explain all evolution. Here, the organism has, in effect, been discarded and only lip service iS paid to the developmental inter- actions necessary for producing the required changes in phenotype‘.

D.B. Roberts

Genetics Laboraton/, Dept of Biochemistry, University of Oxford, South Parks Rd, Oxford OX1 3OU, UK.

mnctunng Punctuation

Genetics, Paleontology and Macroevolution

by Jeffrey Levinton, Cambridge Uni- versity Press, 1988. f27.5OLYZ37.50 hbk (xiv + 637 pages) ISBN 0521249333

The title of Levinton’s big book re- calls two events in the history of evolutionary biology: the January 1947 Princeton conference on gen- etics, palaeontology and evolution’; and the October 1980 Chicago con- ference on macroevolution, of which Levinton was a leading organizer.

The Princeton conference has en- tered the records as the occasion when the Modern Synthesis achieved acceptance: there was ‘essential agreement among all the participants on the gradual mode of evolution, with natural selection as the basic mechanism and the only direction-giving force’*. The Chicago conference was a very different thing, seen by one observer as characterized by ‘palpable tension in an atmosphere that was fraught with genuine intellectual ferment’3.

Behind the concord achieved in 1947 was the work of theoretical and population geneticists during the 193Os, and the achievement con- sisted in convincing morphologists and palaeontologists of the rel- evance of that work to their own fields. Behind the discord evident in 1980 was the work during the 1970s of morphologists, theoretical and molecular geneticists, and especially

palaeontologists, which seemed to challenge the Modern Synthesis. The most important, or best publicized, of those new ideas was Eldredge and Gould’s theory of punctuated equilibria, framed around the obser- vation of apparent long-term stasis of species in the fossil record.

Levinton’s title is well-chosen, for his book fits perfectly into this back- ground and may well come to be seen as a new synthesis setting the stage for evolutionary biology in the 1990s. Levinton played a major part in the Chicago macroevol- ution meeting and the three chief advocates of punctuated equilibria (Eldredge, Gould, Stanley) are the most frequently cited authors in his text. Nevertheless, one of the main thrusts of the book is to sweep punc- tuated equilibria aside. He writes that the hypothesis ‘is inviable’ or ‘in- valid’; that its supposed challenge to neo-Darwinism ‘is bogus’; and that it represents ‘the new essentialism’. Further, it is a measure of the suc- cess of the proponents of punctuated equilibria ‘that many of the architects of the Modern Synthesis and their disciples have been forced into the position of defending a position in which they had never believed’- the straw man of phyletic gradualism.

Levinton’s advantage is that he is a palaeontologist who has taken the trouble to familiarize himself with an extraordinary range of topics in genetics, ecology, morphology, ontogeny and systematics. The book is given weight by its 88-page bibli-

ography, an arsenal that he employs most effectively. The overall im- pression I gained is of encyclo- paedic reading, and level-headedness rather than committed advocacy.

Apart from an overture (defining the field and emphasizing the im- portance of hierarchy) and a rousing coda, the book is divided into seven long chapters, each covering a major topic. Levinton defines macroevol- ution in terms of ‘character-state transitions that diagnose evolution- ary differences of major taxonomic rank’, so that the topic is rooted in systematics: without cladistic analy- sis, and a taxonomy aimed at map- ping genealogy, there is nothing to explain. Systematics therefore occu- pies the first major section, followed by genetics, speciation, ontogeny, and form and function.

The final two sections cover his home ground, the fossil record, and deal with patterns of change in mor- phology, diversity, origination and extinction. I see the chapter on pat- terns of morphological change in fossils as the core of the book, and it is here that he tries to give punctu- ated equilibria the coup degrsce. But surely, punctuated equilibria will not be disposed of so easily, for as Levinton says, the ‘theory cannot be tested in the fossil record’, yet there is nowhere else where one might hope to test it.

The dominant message I found in these chapters on fossils (perhaps merely illuminating my own preju- dices) is how extraordinarily difficult

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TREE vol. 4, no. 3, March 1989

it is to glean reliable information with any generality from the records in the rocks. For instance, one of Levinton’s best examples of the pre- dominance of ‘gradual evolution’ is Bell et a/.‘s study4 of five characters in a Miocene stickleback from varved lake deposits. Yet a new analysis of this example5 leads to the con- clusion that none of the characters shows ‘time trends except by appeal to other sources of data’.

The book is written as a text, with a summary of ‘The Main Points’ at the end of each chapter, but the student

Temperate Frugivory and Seed Dispersal

Birds and Bark A Study of an Ecological Interaction

by Barbara and David Snow, T&AD Poyser, 1988. f16 (268 paged ISBN 0856610496

Nearly two decades have elapsed since the publication of David Snow’s seminal paper on the evol- utionary implications of avian fru- givoryl. Following his lead, theor- etical extensions appeared in the next few years2f3, and studies on the evolutionary ecology of the inter- action between avian frugivores and bird-dispersed plants have prolifer- ated since then.

Earlier field studies and theoretical formulations of plant-frugivore in- teractions were largely concerned with tropical forests. This was perhaps the logical consequence of the fact that fruits and frugivores tend to be most conspicuous, abun- dant and diverse in these habitats. Thus our knowledge of the natural history of plant-animal interactions for seed dispersal was for some years largely based on studies con- ducted in tropical habitats, as rela- tively few investigations were per- formed elsewhere. The notion be- came established that the production of fleshy fruits by angiosperms and their consumption by vertebrates was a quintessentially tropical phe- nomenon4. As more data have emerged from temperate-zone re- search during the last decade, students of frugivory and seed dis- persal are beginning to dispute the claim that the ecology of plant- animal interactions in the temperate zone is downright uninteresting, and numerous investigations have proven that plant-animal inter- actions for seed dispersal are fun- damentally similar everywherer+.

or budding disciple will find that these summaries are no substitute for a careful reading of the text. My only real criticism concerns the physical appearance of the text, for typeface and imprint give the feel of a poor photocopy.

In any event, Levinton’s learning, the clarity of his style, and his down- to-earth approach will secure him a place on the shelf, and will surely also win disciples ready to join him in the defence of the synthetic theory of evolution.

Win Patterson British Museum (Natural History), London SW7 5BD,

UK.

1 Jepsen, G.L., Simpson, G.G. and Mayr, E. ( 1949) Genetics, Paleontology and Evolution, Princeton University Press 2 Lewin, R. (1980) Science 210,883-887 3 Mayr, E. (1980) in The Evolutionary Synthesis (Mayr, E. and Provine, W.B., eds), pp. 148, Harvard University Press 4 Bell, M.A., Baumgartner, J.V. and Olson, EC. (1985) Paleobiology 11, 258-271 5 Bookstein, F.L. (1988) Evol. Viol. 23, 369-398

This book, on bird-fruit inter- actions in a temperate habitat (though a heavily man-modified one), thus comes at a moment when the study of plant-frugivore interac- tions outside the tropics is no longer considered irrelevant to our under- standing of the phenomena of fru- givory and seed dispersal by ver- tebrates. Rather paradoxically, its authors are the same who, in the 1960s and early 197Os, produced those very detailed field studies on tropical frugivorous birds that large- ly fuelled the development of a tropi- cally based theory of plant-frugivore interactions.

The book is organized into two parts. The first and main part pro- vides a straightforward natural his- tory of fruit-eating by birds in a small area of southern England, with some comparison with other parts of Bri- tain and Europe. It is based on ex- tensive observations (totalling 1673 hours) on fruiting plants of all species occurring in the area.

For plants, detailed results are pre- sented species by species including, for each one, information on phenol- ogy, the birds that eat its fruits and their foraging behaviour, and a brief discussion of published obser- vations from other parts of Britain and from continental Europe. The authors have conducted a particu- larly thorough search of the scat- tered European literature on avian frugivory, and should be com- mended for this.

For the birds, a similar species- by-species account is presented, in- cluding detailed information on for- aging behaviour and fruit handling methods, with reference to their role as either legitimate seed dispersers or seed/pulp predators. Particularly interesting are the accounts of ter- ritorial behaviour by some frugi-

vores like the mistle thrush (Turdus viscivorus), and of the unanticipated role of the woodpigeon (Columba palumbus) as a legitimate seed dis- perser for some plants. As a whole, the first part of this book is the most detailed description of the natural history of a plant-frugivore system at the community level that I have ever read. One has only to regret that it refers to such a heavily man- modified environment.

The second part of the book con- sists of short chapters containing evolutionary interpretations of the natural history observations pre- sented in the first part. Current views about the ecological implications and evolutionary origin of patterns of fruit colour, phenology, compe- tition between plants for dispersers, and frugivores’ foraging behaviour, fruit selection, digestive physiology, and time and energy budgets, are examined in turn. As the book is deliberately confined to birds and plants, and other ecological agents potentially influencing their inter- action (e.g. invertebrate fruit pred- ators) are not accommodated in the scenario, the emerging picture is necessarily an incomplete one.

I would recommend this book to anyone interested in plant-animal interactions, who will find in the first part a mine of natural history infor- mation, most useful for comparative purposes; and to ornithologists and botanists alike, who will find in the second part a readable introductory account of one of the clearest examples showing that the organ- ization of nature’s complexity often bears little relationship to the way our universities are usually depart- mentalized.

Carlos M. Herrera

Estacibn Biobgica de Dofiana, E-41013 Sevilla, Spain.

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