CROTCHETS & QUIDDITIES Good Vibrations: The Silent Symphony of Life

Look at the life around you. Everywhere, you are confronted with modularity and repetition, from the leaves and branches on plants, to your hair and the skeletal and other structures within you. Modularity, segmentation, and repetition are, like measures and tones in music, the way in which the living opus has been assembled by the composing processes of evolution. In his elegant book Evolution Emerging, W.K. Gregory (1951) likened modular (“polyisomeric”) organization to “the notes in an octave . . . evolution emerging has involved an infinite number and variety of natural polyisomeres in both space and time.” This has long been known, but little analyzed, in modern evolutionary terms until very recently. To continue the musical analogy, we can view patterned structures as a harmony of organization, with many parts integrated to form an organism, the way the violins, horns, flutes, and so on, form an orchestra. In fact, old ideas and new facts suggest that musical similes are relevant to the symphony of life. Soon after Darwin published his Origin of Species, opponents of his views began marshaling their evidence. One of the first prominent biologists to assemble objections was St George Jackson Mivart (1870), previously respected by and on good terms with Darwin, Huxley, and the rest of the biological “in” crowd. The main issue was whether adaptive natural selection could explain species variation and evolution. Mivart so irritated Darwin that he responded at great length in the 6 edition of Origin. Some of Mivart’s objections involved the nature of inheritance and homology in regard to discontinuous variation, such as repetitive, serially homologous structures. Mivart became a bête noir who was ostracized by the Darwinian community then becoming the mainline of biology. Mivart also tried to reconcile evolution and Catholicism, and was excommunicated from that church, too, poor fellow. But his theme was picked up by W.K. Brooks in the US who credited Mivart and then by William Bateson (1892, 1894, 1913, see Webster, in Bateson, 1894; Webster and Goodwin, 1996). Bateson coined the term “genetics” and was a strong promoter of Mendelian genetics, but he did not think that the darwinian evolution by gradual natural selection could generate species or their diversity (e.g., Bateson, 1913). He pointed out problems in interpreting modular (repetitive, serially homologous, or meristic) structures: “Segmentation . . . is almost universally present . . . greater or less repetition of various structures is one of the chief factors in the composition of animal forms.” (Quoted in Webster’s preface to Bateson, 1894). But discrete segment numbers cannot evolve incrementally. What is actually inherited? A different gene for each hair or vertebra? That made no sense to him, and it may have been a reason for the non-specific suggestion a century later that evolution was a “punctuated” process. One of his ideas about this is strikingly modern in concept. The suggestion drew biological parallels with concepts of fields and vibrations or oscillations borrowed from physics. As we’ll see, Bateson used a musical analogy that makes some evolutionary genetic points easy to understand. There were then no actual genes known and his views were ignored or even ostracized during the decades of ascendance of the neodarwinian synthesis. But the basic ideas are enjoying a justified revival in a profound advance in our understanding of the role of genes in the evolution and generation of complex morphologies. We can trace these ideas, at least fancifully, back to the famous GeoffroyCuvier debates in 1830 on the nature of animal form itself, and perhaps even push the musical analogy back to that time as well.