Anniversaries are the last refuge of the journalist and 2009 is no exception. Happy 40th, then, to the Moon landings, felice quattro centesimo compleanno to Galileo's telescope, and glücklich vier Hundertstel Geburtstag to Kepler and his laws of planetary motion. One birthday boy gets two slices of cake, for Charles Darwin is 200 this year and his best-known book is 50 years younger. To look back on his life is to be astonished by his almost uncanny ability to predict the course of biology to the present day and beyond.
The Origin of Species is one of those tomes that everyone knows but nobody has read - but it is only one of Darwin's many works. They could, together, celebrate more than a dozen birthdays over the next several decades - and they deserve a few crumbs from the 2009 table as a reminder of how much they, too, set the agenda of modern science.
The Origin's “long argument” invented the science of biology, and every modern biologist works in its shadow. Many of its pages are devoted to individual differences, the raw material of evolution. Darwin could write only about what he could see, but now genetics tells us that every sperm and every egg made by all the billions of men and women who have walked the Earth since our species began is unique; a figure once unimaginable.
The sequencing machines that will soon read off anyone's DNA in a few hours are a direct descendant of Darwin's expert scalpel - anatomy taken to the next level. His sketch of an evolutionary “tree” has been succeeded by computer databases that make universal pedigrees of life. Farmers, whose work opens that famous volume, now go back to the wild to extract genes for flavour or yield, and breed from the best far more effectively than the Victorians could. Darwin never thought he would see the “survival of the fittest” in action; now, from the Aids virus to the lengthening legs of the cane toad as it spreads across Australia, that observation is commonplace.
Most of the great man's later work was just as ingenious. He wrote on barnacles, orchids, domestication, human evolution, the expression of emotions, carnivorous, climbing and sensitive plants, the origin of sex and on earthworms. His books are filled with discoveries that would - even if The Origin had never been written - have made him famous.
Who knows that Darwin wrote one of the first scientific publications illustrated with photographs? The pictures of an aged Frenchman “of feeble intellect”, whose face was stimulated with electric probes to give a look of horror appear in his Expression of the Emotions. Brain scans, with their claims for centres of religion, guilt or kindness, are direct descendants of that work. Darwin saw the problems involved in studying inner sentiments - how do you define a smile, where does the cheek or forehead begin and end? Perhaps, in time, his electronically entranced descendants will learn some of his caution.
Darwin also discovered the first hormone (in plants rather than animals). A slim beam of light on the very tip of a shoot caused the stem lower down to bend towards light; proof that “influence is transported” from the sensitive tip to the growing part of the plant. That too was a spark that ignited a fury of research. Darwin's garden became a laboratory. He was concerned that his marriage to his cousin Emma might damage his offspring because of inbreeding - and he studied that question in flowers (where it did seem to be harmful); and in Oxbridge colleges (where members of boat-race crews were less likely to be the children of cousins than the broad mass of undergraduates). Now it seems that inbreeding does have a slight effect on human health - but in most places is outweighed by the tendency of women to delay having children and the undoubted harm so caused.
The Descent of Man led to the great change in our view of ourselves. In 1841 Queen Victoria went to London Zoo. She was less than amused: “The Orang Outang is too wonderful... he is frightfully, and painfully, and disagreeably human.” Darwin, too, spotted the resemblance and made an incontrovertible case that, as Gilbert and Sullivan later put it, “Darwinian man, though well behaved, at best is only a monkey shaved”. His famous phrase that “light will be thrown on the origin of man and his history” has been mightily justified by modern biology.
We have, though, as its author realised, one evolutionary talent that makes us unique - the ability to respond to life's challenges not with bodies but brains. Adam and Eve were unashamed, but after the first (and least original) of all sins they made aprons to hide their nether parts. Lice suggest when they put them on. When humans emerged on to the sunny savannahs they lost their hair, perhaps to cool down. The lice had a hard time and evolved to live in the few patches of habitat left. We now have three kinds, the head and body louse, plus the pubic louse. Only the body louse hangs on to clothing. DNA shows that it split from the head form no more than 50,000 years ago - which may mark the moment we dressed ourselves. As we did, we took the first steps of the long journey into civilisation.
That universal attribute now means that most of what makes us what we are happens not in our bodies, but our minds. Darwin, as a result, did not diminish Homo sapiens but set him apart on a mental peak of his own. His theory does not render us less human than before, but far more so: a unique primate indeed. A century and a half after Queen Victoria's disagreeable experience, I gave a talk at London Zoo pointing this out - and most of the apes agreed.
Steve Jones, Professor of Genetics at University College London. His new book is Darwin's Island.