Ego and excellence are on display in these sketches of Britain's top evolutionary biologists, says Paul Harvey
Ever since Alfred Russel Wallace and Charles Darwin, evolution by natural selection has been used to explain why animals and plants do such a good job of exploiting their environments. Generalisations of the theme, such as sexual selection and kin selection, have been developed to incorporate the apparent exceptions. Also, of course, the discovery of genetics started a long and difficult process of bringing genes into evolution.
Along the way, the UK has produced more than its fair share of pre-eminent evolutionary biologists. Despite differences in approach, the common driving force in their work has been to explain natural variation in and among species in adaptationist terms. At times their interpretation of natural history and genetic change has required algebra and statistics, frequently coincident with (or followed by) the collection of new long-term observational or experimental data. In A Reason for Everything , Marek Kohn makes sense of it all using for the most part in-depth biographical sketches of the key players (except Darwin, whose life and work are well known and anyway pervade the book).
Kohn selects Wallace, Ronald Fisher, J. B. S. Haldane, John Maynard Smith, Bill Hamilton and Richard Dawkins for the meat of his account. Wallace was the enquiring naturalist. Fisher, Haldane and Maynard Smith were mathematical formalisers who ensured that verbal arguments were based on logical foundations. Hamilton was accomplished both as a naturalist and as a theoretician. Dawkins is a remarkable writer whose easy prose conveys state-of-the-art theory and takes no prisoners. Between the sketches of Fisher and Haldane, a chapter on the "Oxford School" describes the work of David Lack, Philip Sheppard, Arthur Cain, E. B. Ford and others, which revealed and measured the selective pressures acting on populations of organisms in the wild, mainly birds, insects and snails. Their selective coefficients were frequently more than an order of magnitude larger than expected or necessary for rapid adaptive evolution in the face of stochastic drift.
Inspired by Cain and Sheppard, my own research career started with measuring selection in populations of the snail Cepaea. I went on to work in the same departments as Maynard Smith, Hamilton and Dawkins.
I would not have believed that any single author could have got everything so right about these people. Kohn's biographical sketches lay bare their personalities, their influences, their modus operandi and their achievements. All facets are displayed, with the science explained precisely and clearly for the non-professional and the historical narrative flowing through the book as our understanding of evolutionary processes develops. I think the only person whose contribution Kohn overplays, is Ford. He was indeed "camp" and well-connected, and did indeed measure selection in the wild. Yet, like some others who have read his research papers and his Ecological Genetics , I continue to wonder what all the fuss was about.
Of the protagonists, only Dawkins is still alive and a worthy torch-bearer of the "English" tradition. But, as Kohn explains, he is much more than this. Dawkins attempts to make us see the natural world differently, whether we are lay readers or professional scientists, including evolutionary biologists. His contributions are not frequent but they can be profound. Starting in 1976 with The Selfish Gene , he taught the rest of the world how population geneticists think. Then came The Extended Phenotype , a book for evolutionary biologists, which investigated the consequence of genes having selective effects beyond their bearers frequently influencing other individuals, including other species. Haldane had written: "Fitness is a bugger." That was before The Extended Phenotype explained the different concepts of fitness. Now Dawkins has returned with a more original contribution, The Ancestor's Tale , which traces evolution backwards through the most recent common ancestors of humans to ever more distantly related but contemporary species. His new book appeared after Kohn finished writing his; I guess that any revised edition of A Reason for Everything will include rather extensive reference to The Ancestor's Tale .
Kohn's main characters did not work in isolation from overseas biologists such as Sewall Wright, Ernst Mayr and Theodosius Dobzhansky. Their work, too, is well woven into the narrative. Although the book is unashamedly Anglocentric, this does not stop Kohn from mentioning the less appealing aspects of these strong personalities. On occasion, egos clashed, bringing out the worst in one or both sides. Hamilton never forgave Maynard Smith for his early treatment of Hamilton's concept of inclusive fitness ("kin selection"). Those of us who knew both Hamilton and Maynard Smith drew our own conclusions long ago about who was more or less in the right, but Kohn, to his credit, lays out the facts, with quotations from their personal correspondence. There were other battles over the relative importance of different evolutionary processes, for example between Fisher and Sewall Wright over selection and drift, which are exposed too, often with the benefit of hindsight.
Three elements in Kohn's book contribute to its success. He has put huge spadework into interviewing, where available, those at the centre of his stories, as well as their colleagues, friends and families. He has bothered to understand the science properly, including that which was new at the time, and what difference it made. And he is a talented and witty writer, which makes his well-digested mix of biography and science read like a well-constructed novel.
Paul Harvey is head of zoology, Oxford University, and secretary of the Zoological Society of London.
A Reason for Everything: Natural Selection and the English Imagination
Author - Marek Kohn
Publisher - Faber
Pages - 392
Price - £20.00
ISBN - 0 571 22392 3