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Darwin's masterpiece revisited
This month marks the 150th anniversary ofthe most influential piece of popillar science writing ever published A few years ago, New Scientist listed reading On The Origin ofSpecies as one ofthe 100 things to do before you die. To do so is to experience the extraordinary sensation ofhaving a scientific genius enter your mind to guide you through his most important theory. Now we have asked the geneticist, evolutionary thinker and author Steve Jones to summarise and update the book for the 21st century - and, we hope, to inspire readers to experience. Darwin's astounding, world-changing writing first-hand NIQUE among scientific theories, evolutionary biology finds its roots in a popular book by a single author. The grey-bearded genius presented a new and radical view of existence: that life has changed overtime and space, in part through a simple process called
U
natural selection. Charles Darwincalled his work "one long argument". To a 21st-century reader it seems lengthy indeed, with onlya single illustration to enliven its 150.000 words. But Darwin was a clear thinker and the book is an impressive piece ofadvocacy, moving from the familiar- how animals on farms have changed - to the less so, embryos and instinct included. Darwin also shows how what might seem to be problems for his argument, such as the uncanny perfectionofcomplex structures like the eye, are in fact part ofthe solution, and how apparent weaknesses inhis case-the incomplete nature of the fossil record included - can easily be explained. Now and again he was wrong. as when, unaware of Gregor
Mendel's work on genetics, he claimed that inheritance is based on the mixing ofbloods, but mostly he was right. Darwin described the process ofevolution as "descentwith modification". Today that might be rephrased as "genetics plus time". Offspring resemble their parents because they inherit DNAfrom them,
but the copying process is not precise. Every round has errors, or mutations, and although they are individually rare -with perhaps one or two mutations in working genes each generation in humans -they can soon bulid up vast diversity. Acopy of a copy is always Imperfect, and for that reason alone, evolution is inevitable. Darwin had a second insight. He saw that ifa certain variant allows its carriers to survive, to mate and. to pass on their heritage more successfully thanothers, in later generations it will spread. Such inherited differences in the chances ofreproduction allow creatures to adapt to changing circumstances and can, in time, give rise to newforms ofllfe. Natural selection, as hetermed it, is a factory for making almost Impossible things. The Origin was written in something ofa rush. When Darwin discovered that Alfred Russel Wallace had hit upon thevery idea he had
been cultivating since soon after his retumfrom the Beaglevoyage, he condensed and refined his plan for amuch longer book and set out to bring his theory to a wide audience. The book is far shorter than that first scheme, but as a result it is much clearer-which is, no doubt, why it made such an Immediate Impact. Darwin apologised again and again for leaving so much out and spent much ofthe rest ofhis life filling in the gaps. IfI'he Origin was ahasty letterto its readers, this account is no more
than a postcard. But I hope that in just afraction the length ofits archetype it sketches out how Darwin might make his case today,
acentury-and-a-halfon.
Pagetwo 1NewScientist 114 Navember2009
CHAPTER ONE Variation under Domestication In which Darwin uses exnmplesfrom domestication to explore the causes of
variobilityand the principles ofselection Fanners have beenunwitting evolutionists
since they began, as they have shaped the
characteristics ofdomesticated species. Nowhere is the powerofhuman selection more clearly seen than by the fireside. Dogs
were domesticated around 16,000 years ago in China, perhaps for meat. Their ancestors were wolves - and the two still share the same scientific name, Canis lupus - but dogs have changed mightily since then. The breeders were ruthiess, killing off the animals of
U
natural selection. Charles Darwincalled his work "one long argument". To a 21st-century reader it seems lengthy indeed, with onlya single illustration to enliven its 150.000 words. But Darwin was a clear thinker and the book is an impressive piece ofadvocacy, moving from the familiar- how animals on farms have changed - to the less so, embryos and instinct included. Darwin also shows how what might seem to be problems for his argument, such as the uncanny perfectionofcomplex structures like the eye, are in fact part ofthe solution, and how apparent weaknesses inhis case-the incomplete nature of the fossil record included - can easily be explained. Now and again he was wrong. as when, unaware of Gregor
Mendel's work on genetics, he claimed that inheritance is based on the mixing ofbloods, but mostly he was right. Darwin described the process ofevolution as "descentwith modification". Today that might be rephrased as "genetics plus time". Offspring resemble their parents because they inherit DNAfrom them,
but the copying process is not precise. Every round has errors, or mutations, and although they are individually rare -with perhaps one or two mutations in working genes each generation in humans -they can soon bulid up vast diversity. Acopy of a copy is always Imperfect, and for that reason alone, evolution is inevitable. Darwin had a second insight. He saw that ifa certain variant allows its carriers to survive, to mate and. to pass on their heritage more successfully thanothers, in later generations it will spread. Such inherited differences in the chances ofreproduction allow creatures to adapt to changing circumstances and can, in time, give rise to newforms ofllfe. Natural selection, as hetermed it, is a factory for making almost Impossible things. The Origin was written in something ofa rush. When Darwin discovered that Alfred Russel Wallace had hit upon thevery idea he had
been cultivating since soon after his retumfrom the Beaglevoyage, he condensed and refined his plan for amuch longer book and set out to bring his theory to a wide audience. The book is far shorter than that first scheme, but as a result it is much clearer-which is, no doubt, why it made such an Immediate Impact. Darwin apologised again and again for leaving so much out and spent much ofthe rest ofhis life filling in the gaps. IfI'he Origin was ahasty letterto its readers, this account is no more
than a postcard. But I hope that in just afraction the length ofits archetype it sketches out how Darwin might make his case today,
acentury-and-a-halfon.
Pagetwo 1NewScientist 114 Navember2009
CHAPTER ONE Variation under Domestication In which Darwin uses exnmplesfrom domestication to explore the causes of
variobilityand the principles ofselection Fanners have beenunwitting evolutionists
since they began, as they have shaped the
characteristics ofdomesticated species. Nowhere is the powerofhuman selection more clearly seen than by the fireside. Dogs
were domesticated around 16,000 years ago in China, perhaps for meat. Their ancestors were wolves - and the two still share the same scientific name, Canis lupus - but dogs have changed mightily since then. The breeders were ruthiess, killing off the animals of