Book reviews

Journal of Human Evolution (1988) 17, 367-378

Sewall Wright and Evolutionary Biology

By William B. Provine (1986) Chicago: University ofchicago Press. ISBN 0-226-6X674-1,

$30.00 (cloth). Evolution: Selected Papers by Sewall Wright

Edited by William B. Provine (1986) Chicago: University of Chicago Press. ISBN

o-226-91053-9, $70.00 (cloth); ISBN o-226-91054-7, $25.00 (paper).

Sewall Wright* is probably rivalled only by Claude L&i-Strauss as the greatest

unintelligible genius of our time. His work was incomprehensible to Dobzhansky,

misapplied by Simpson, misunderstood by Mayr, and misrepresented by Fisher. The

present reviewer consequently makes no pretenses, let it be duly noted. In Sewall Wright and Evolutionary Biology, however, historian of science William Provine combines a biography of

Wright with a critical evaluation of his place in evolutionary theory. This is complemented

by Evolution: Selected Pafiers, in which Provine reprints and introduces some of Wright’s

publications.

The Wright “biography” is a masterpiece of intellectual history, the product of a

monstrous investment in exegesis, interviews, and critical scholarship by Provine. It is,

however, only a biography in the loosest sense of the term. While the reader is confronted

with the definitive work on Wright’s contributions to evolutionary biology, s/he learns

astonishingly little about Wright’s life. Though Wright was 25 at its outbreak, there is not a

mention of the First World War, which did affect many people’s lives. The Great

Depression is similarly spared mention. The impact of World War II was four-fold,

judging from the print it receives: it inconvenienced geneticists attempting to return from

the 1939 International Congress of Genetics at Edinburgh; it delayed the publication of

David Lack’s ornithological monograph; it postponed Wright’s receipt of reprints ofa 1939

monograph he had published in France; and it gave Wright an excuse to withdraw from

further collaboration with Dobzhansky on the Genetics of Natural Populations. (Wright’s

excuse, quoted in correspondence, was that he was “a statistical consultant on several war

projects”, and elsewhere mention is made his of estimation of radiation danger from the

A-bomb.)

Right or wrong, the impression conveyed by Provine’s life of Wright is that of a cloistered

academic, out of touch with anything and everything that hasn’t directly impinged on

* Sewall Wright died on 3 March 1988

368 BOOK REVIEWS

guinea pigs or theoretical population genetics. Whether this reflects Wright’s life, or merely refracts Wright’s life through Provine’s eyes, is impossible to say. Provine mentions

Wright’s lack of support for the eugenics movement, but this fell far short of opposition to it; Provine doesn’t mention Lysenko, the Stalinist scourge of 20th-century genetics-we don’t know whether Wright felt or thought anything about that, either.

The bulk of Provine’s efforts in the biography, however, are martialled toward elucidating Wright’s position in the intellectual history of evolutionary biology, and to this end the work is brilliant. The climax of Provine’s analysis is his demonstration of the protean nature of Wright’s own views:

From the beginning, Wright saw his shifting balance theory as ultimately adaptive. More specifically, the process was adaptive at the level above the effective action of genetic drift. But what systematists said in the late 1920s and early 1930s told Wright that differences between species were non-adaptive. Thus Wright adjusted the “balance” in his shifting balance theory to favor the controlling action of random drift at the species level and below, the selective/adaptive levels being primarily those above the species level.

(I) t was precisely the linkage Wright drew between random drift and observable nonadaptive differences that made the greatest impression upon contemporary evolutionists, who do not seem to have understood the adaptive aspects of Wright’s theory. As systematists moved toward the view that differences at the species and subspecies levels were adaptive rather than nonadaptive, they no longer thought random drift could cause those differences. All Wright had to do was move downward on the taxonomic scale the level at which random drift was effective, which was very easy to do (p. 455).

The reason Wright could shift his shifting balance (and then deny he ever did it) was that few biologists could/can comprehend it in any but a generally metaphorical sense. Just as it is often much more productive to read what So-and-So says Levi-Strauss said than to read what Levi-Strauss himself said, likewise with Wright. Wright’s scientific papers were candidly evaluated by Dobzhansky, no dummy:

Wright is hard to read. He has a lot of extremely abstruse, in fact almost esoteric mathematics. My way of reading Sewall Wright’s papers, which I still think is perfectly defensible, is to examine the biological assumptions the man is making, and to read the conclusions he arrives at, and hope to goodness that what comes in between is correct (quoted on p. 346).

Wright has, however, made an effort time and again to present his ideas to an audience not composed of mathematicians. Many of these papers appear in the compendium Evolution: Selected Papers, alongside the more mystifying but important ones. Wright, of course, is solely responsible for formalizing the studies of inbreeding and population structure. Thus his impact on microevolution has been substantial, but the relationship to macroevolution has most often required a metaphorical leap of a mystical bewilderment. Wright’s reviews of Simpson’s Tempo and Mode in Evolution and Goldschmidt’s The Material

Basis of Evolution, both written in the 1940s for The Scientijc Monthly are of great interest in this regard, and Provine relates that the paper given by Wright at the famous 1980 Macroevolution conference (also reprinted here) engendered more reprint requests than any other of his 210 (as of 1984).

Also included are Wright’s most cited papers, “Evolution in Mendelian Populations” from 1931 (the one that is always mentioned between “Fisher 1930” and “Haldane 1932”)) and “The Roles of Mutation, Inbreeding, Crossbreeding and Selection in Evolution” from the following year, which introduced the adaptive landscape to an unsuspecting world. The most interesting inclusion is “Statistical Genetics in Relation to Evolution”,

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mentioned above in connection with World War II, which is fairly clear (for Wright), and

very rare. It need hardly be stated, but certainly anyone who thinks that the disagreements

between, say, Leakey and Johanson are unparalleled in the “harder” sciences should read about Wright and Ronald Fisher. Provine laudably summarizes and reprints their arguments about the evolution of dominance and the relative importance of population subdivision, which effectively polarized population genetics into American and English schools for decades.

In sum, Provine has taken us upon a scholarly journey into the history and theory of evolution. For the mechanistically inclined, the works are of great importance in helping piece together just what is going on at the genetic “level” in a species. And for the historically inclined, the works will be indispensable.

JON MARKS

Department of Anthropology,

Yale University,

New Haven, CT 06520, U.S.A.

Handbook of Paleozoology

By Emil Kuhn-Schnyder and Hans Rieber (1986). Johns Ho&kins Studies in Earth and

Planetary Sciences. Baltimore, Maryland: The Johns Hopkins University Press. xi + 394 pp. $32.50. ISBN o-8018-2837-7. (Translated by Emil Kucera.)

This book presents a well-illustrated summary of fossil animals, including a classification, briefcharacterizations of major taxa (i.e., characters, geological range, characteristic fossil remains) and occasional digressions to illustrate important morphological phenomena or complex characters. Rieber reviewed the invertebrate phyla and Kuhn-Schnyder summarized the vertebrates. Although the focus is on fossils, extant taxa and information that is typically absent for fossils (e.g., soft tissue, physiology, behavior) is discussed. The bulk of the book is a classification with characterizations and abundant illustrations incorporated at appropriate points. It closes with a summary classification, a selected (50 citations) bibliography, an index to genera and species, and a subject index, which includes names of higher taxa.

The space devoted to different groups reflects their abundance and importance in the fossil record. About a third of the book is devoted to invertebrates, with the Mollusca understandably emphasized. Then follows a brief discussion of vertebrate morphology, and the remaining text takes up vertebrate classification. About a quarter of the entire text concerns the Mammalia, with systematic treatment down to the level of families, Scant attention is given to the agnatha, gnathostome fishes, and Amphibia. Although about 10% of the book is devoted to reptiles, dinosaurs are emphasized. There is a six-page section on the Order Primates.

The illustrations are the strongest aspect of the book. Consisting of line drawings usually modified from published sources, they are especially useful for teaching. In addition to drawings of whole specimens, including restored skeletons, and portions of skeletons (e.g. pes, manus, palate), there are simplified phylogenies, cross-sectional diagrams, restora- tions, and illustrations of specialized characters (e.g., mammalian middle ear, ammonite sutures). Occasional tables summarize classifications or character state distributions.