Niles Eldredge

REINVENTING DARWIN

The Great Evolutionary Debate

Together with Stephen Jay Gould, Niles Eldredge is one of the originators of the theory of punctuated equilibrium. This holds that most sexually reproducing species persist with little change for most of their geological history ("stasis"). When change does occur it is relatively rapid, with splitting of a species into two different species rather than the gradual transformation of one species into a new one. The theory has been the source of much contention among evolutionary scientists and has been seized on by opponents of evolution as casting doubt on the fundamentals of evolution. In this book Eldredge seeks to remove what he takes to be misunderstandings about his and Gould's ideas.

He starts by using the metaphor of a High Table, which is the area of the dining hall at a British college where the elite of the instructional staff sit. The dominant view of evolution at the High Table is what Eldredge calls ultra-Darwinism. It is held, for example, by John Maynard Smith, Richard Dawkins, and George Williams. Opposite them sit those whom Eldredge calls "naturalists". They include Gould, Stephen M. Stanley, Elisabeth S. Vrba, and of course Eldredge himself.

Dawkins's books on evolution have presented, Eldredge says, a rather unflattering picture of the naturalists' side of the High Table and a perhaps over-flattering one of Dawkins's own side. Eldredge seeks to redress the balance and does so with good humour and in a pleasant tone. Although the details of the arguments, on both sides, are technical, Eldredge makes a good job of presenting them in a way that will be understandable for readers who are not specialists or even scientists,

The various sections in the book deal with changing ideas about adaptation and natural selection; stasis in evolution; punctuated equilibrium and debates about whether species really exist (Eldredge insists they do); macroevolution; and the nature of complex systems. In his concluding pages Eldredge claims that the naturalists offer "a less assumption ridden, theory laden description of the nature of all manner of biological systems." His claim, essentially, is that their view is a truer picture of nature than that of the "reductionists".

The book presents a very readable account of the debate that will be useful to anyone who wants to understand the issues in some detail. And it makes it clear that the theory of punctuated equilibrium is in no sense a rejection of Darwin's basic insight. It is a variation on a theme but not an entirely different theme.

26 December 2009