Digital Darwin: not apeing books

EVOLUTION. By Mark Ridley. Blackwell Science +44 1865 206179

Pounds 29.50 inc VAT. - ISBN 0 86542 757 7. Macintosh/Windows CD

The most revolutionary book of the 19th century was not Don Juan or even Das Kapital but On the Origin of Species by Means of Natural Selection, published by Charles Darwin in 1859. Ironically, as many a quibbler has pointed out, Origin did not adequately explain the birth of new species, or convince everybody that natural selection is the key to evolutionary change. But it did establish beyond all reasonable doubt that evolution, and not special creation, is the normal way of things: or as John Maynard Smith puts the matter on this CD-Rom, that "all existing animals and plants are descended from some one ancestor many millions of years ago". It took another 80 years or so to merge the evolutionary insights of Darwin with the genetic theory that Gregor Mendel had initiated in the 1860s; and the fusion of the two to produce "neo-Darwinism", alias "The Modern Synthesis", is one of the intellectual tours de force of the 20th century. DNA and all that, is just the icing on the cake.

Indeed, the words of one of the principal synthesisers, the Russian-American geneticist Theodosius Dobzhansky, nothing in biology makes sense except in the light of evolutionary theory - and of course, Darwinian ideas have long since spread beyond the bounds of biology. So now the subject of "evolution" has become more multifarious than the repertoire of Hamlet's Player-King - historical, philosophical, biographical, genetical, and even, these days, psycho-economo-political. It takes a cool head to bring it all together and none is cooler than that of Mark Ridley who, following his flying first at Oxford a decade back, has been paid by successive universities simply to think. This CD-Rom is based on his enormously successful textbook on evolution.

Accordingly, within the limits of the technology and price, the intellectual content seems unimproved. The core consists of five tutorials - foundations of evolution, evolutionary genetics, adaptation and natural selection, evolution and diversity, palaeontology and macroevolution; and these are backed by "browsers", arranged both by "gallery" (Timeline, Classic texts, Experiments, Image Gallery, or Video Gallery), and by an A-Z that runs from Adaptation (the key to Darwin's idea of evolution by means of natural selection) to Zahavi's handicap principle (which holds that the peacock's tail is supposed to be a handicap which tells the female, "Look, I must be genetically well-endowed, since I can survive even though I carry an extra pound-and-a-half of feathers!").

There are also 20 classic papers, for example by Dobzhansky, Sewall Wright and R.A. Fisher (who brought pertinent maths to bear on evolutionary theory) which can be printed in full.

The production, by Pat Kyle, is a wonder of compression and user-friendliness, as neat as a kit-inspection. Some ideas can only be made clear by animation - and CD-Roms can provide them. I particularly like the one that shows D'Arcy Thompson's great idea, that the shape of an animal can be altered radically simply by adjusting the coordinates; a notion that is now very pertinent as biologists explore the "master" genes that control entire regions of growth, like the Hox genes of animals. Animated experiments show, for example, how mutations might spread through a population, with the reader changing the parameters. Film clips provide comments by a dozen luminaries of modern evolutionary theory, including Maynard Smith, Bill Hamilton, Dan Dennett, David Haig, Helena Cronin, Linda Partridge, and Simon Conway Morris - though these, perhaps, are less satisfactory. Some answers are too epigrammatic - including John Maynard Smith's definition of evolution given above, not least for the pedantic reason that "animals and plants" includes only a tiny proportion of total biodiversity, since most are microbes. Others seem too specialist, such as Linda Partridge's reply to "What is fitness?", with its references to genotypes and loci. But it is good to show flesh-and-blood people even if they don't always say what you would like them to.

However, students should know that CD-Roms are brilliant for some things but they are not a substitute for books. Print on paper is better than print on the screen - more legible, more portable. Illustrations and movies on CD-Rom are frankly crude.

But if a CD-Rom is built on good scholarship and put together conscientiously then it is a superb and perhaps unimprovable aide memoire: like very high-class course-notes. This CD-Rom is aimed at undergraduates, and within this plastic "O" is the structure and material for any undergrad essay. But unlike the usual crib, good CD-Roms are seductive. Books are more passive - it's easy to stop; but for some reason these lists of topics, each brought on line with a click, lure you on. I began Evolution in a spirit of cynicism and was hooked - and am now a potential CD-addict. I'm looking forward to the next 20 years, when today's discs will seem like Ford Model Ts, and every student's room will have a flat portable screen a metre across. Even with present technology, however, Evolution is an excellent buy.

Colin Tudge is a visiting research fellow at the Centre for the Philosophy of the Natural and Social Sciences at the London School of Economics.