Gene Expression

i-b26d30171cc3d890e253453d2e3e4488-GOUSTR.jpgChapters read:1, 2, 3, 4, 5, 6 and 7.

And now there have been 5. Through 5 chapters of The Structure of Evolutionary Theory. Stupidly I only realized that Stephen Jay Gould wrote two books which he had insisted be bound together. The table of contents which I was familiar with turned out to be the “Expanded Contents.” The Contents proper give a better lay of the land:

Chapter 1:
      Defining and Revising the Structure of Evolutionary Theory 1

Part I, Chapters 2-7
      The history of Darwinian Logic and Debate 91

Segue to Part II 585

Part II, Chapters 8-12
      Towards a Revised and Expanded Evolutionary Theory 593

After which you have the index, biolography, etc. So you see, my previous complaining that this was rehashing the history of science was selection biased insofar as the there is a book on the history of science which precedes the discussion of contemporary science! In the first chapter Gould makes the case that his peculiar perspective as a paleontologist might give him some distinctive value-added insights; I honestly haven’t seen that yet. He does have some strong opinions on the extent of adaptation and the level at which selection operates which suffuses his narrative. But I don’t think that that truly impacts the intellectual history as such except on the margins; Gould’s own scientific commitments are not slipped in seamlessly as part of the bigger story, rather, they seem to feel like asides, as he interjects his own take in an almost a la carte manner. This chapter focuses on the non-Darwinians who flourished after Charles Darwin and before the Modern Synthesis (roughly the 1880s to the 1920s), and the biographical sketches are generally tight and I see little to object to in the exposition. Confronted with a relative surfeit of material it seems that Gould has corralled his natural inclination to lose control of his prose; at least judged by the metrics of comparison with previous chapters. Though longer in page count that made chapter 5 a quicker read.

1) Francis Galton did not believe in the efficacy of selection to generate the variation we see around us in terms of species. He believed that quantitative processes, such as regression to the mean, meant that continuous variation was of secondary importance to sharp discontinuous jumps. What he termed “sports.” He used an analogy to a polyhedron, which balances with any stability only upon a finite number of sides. Similarly, the nature of biological variation is also subject to constraints, perhaps of a physical nature, which leaves it less continuous than pure Darwinian natural selection might allow us to expect.

2) There were many orthogenetically inclined scholars during the late 19th century who were not theistic evolutionists; rather, they were materialistic formalists who believed that non-selective natural processes were the factors which underly the phenotypic variation and the paths of evolution around us. Stephen Jay Gould wants to defend these early orthogeneticists from the slander that they constructed their theories to be congenial with their religious beliefs; that evolutionary process exhibited a specific directionality. Rather, he contends that many were formalists or structuralists who placed the locus of emphasis upon a different set of processes than Darwinian selectionists. In short, they seem to be the precursors of those who would emphasize the role of developmental constraint.

3) William Bateson was a Mendelian. This is known. But less well known (I believe) is Gould’s explanation that Bateson himself became conservative in his old age and rejected chromosomal theories of inheritance for a “wave” model. Though Bateson accepted the discrete model of inheritance, and saw it initially as a rebuke to biometrical emphasis on natural selection operating via continuous variation, he could never shift his focus to the most likely physical substrate which gave rise to the Mendelian process.

4) Hugo de Vries was even more radical a Mendelian than Bateson. His macromutationist theories of speciation seem to be anticipating models of genetic revolution and hopeful monsters. That being said, Gould recounts how de Vries emotional attachment to Charles Darwin prevented him from acknowledging the fundamentally anti-Darwinian slant of his model. Rather, de Vries attempted to claim that in fact his macromutationist/species selectionist paradigm was in keeping with Darwin’s theories in spirit.

5) Richard Goldschmidt, the father of the “Hopeful Monster,” was a really outrageous figure whose penchant for egotism and exclamation got the better of him, making the counter-attack from the exponents of the Modern Synthesis more uncompromising than it might have been. That being said, many of the high priests of the Synthesis set up in Goldschmidt as a strawman to use as a foil, but never read his original work with an open mind. He was ignored, not engaged.

Comments

  1. #1 leigh
    February 11, 2008

    Goldschmidt did a great deal more than hopeless monsters. I was with Dobzhansky when he heard of Goldschmidt’s death. I’ve preserved his comment: “A great geneticist has just died.”

The site is currently under maintenance and will be back shortly. New comments have been disabled during this time, please check back soon.