The Origins of Life: From the Birth of Life to the Origin of Language (review)

The Origins of Life: From the Birth of Life to the Origin of Language, by John Maynard Smith and Eors Szathmary. Oxford, UK: Oxford University Press, 1999. 180 pp.

Darwin's theory of natural selection is one that most people can wrap their minds around with little coaxing. There is something obvious in the notion that those individuals best able to survive and reproduce will pass on to their offspring those traits that enabled them to do so. So common-sensical is Darwin's insight that upon hearing it, the great 19th-century biologist T.H. Huxley reportedly said, "Why didn't I think of that?"

Not so the question at the heart of this slim but dense volume. Why have some lineages of organisms become more complex? As John Maynard Smith and Eors Szathmary rightly observe, nothing in Darwin's theory predicts it should have happened. To the contrary, the more parts an organism has, the more that can go wrong. And yet while things can and have gone wrong over and over in the evolution of complex organisms, they have also gone right a remarkable number of times.

It is tempting to read The Origins of Life as an epic success story. The book, subtitled From the Birth of Life to the Origin of Language, spans such achievements as the emergence of genetic code, the nucleated cell, sexual reproduction, multicellular organisms, the rise of sociality and, finally, of modern human societies. Yet what is remarkable is how the authors manage to sidestep the teleology that plagues so many accounts--the feeling that it was somehow all inevitable. At the outset, they describe evolution as a unique series of events." Any one of them might not have happened, and if not we would not be here, nor any organisms remotely like us (p. 19), they write.

However unique, their story is not a haphazard or random one--and it would be nearly impossible to tell such an epic tale without a designing principle. What gives shape to the story, makes it come alive, is its adherence to a version of the controversial principle of "group selection." Maynard Smith and Szathmary claim a different organizing principle. They say that the central argument of their book, one that defines even their choice of turning points, is that "complexity has depended on a small number of major changes in the way information is stored, transmitted and translated" (p. 16). But the more dramatic and compelling theme--played out in chapter after chapter--is that units which were once separate and competitive found it mutually advantageous to coordinate their activities. Indeed, cooperation between such elements is what causes the major transitions in the way information is stored and transmitted.

While cooperation is the theme, this is no warm and fuzzy account. As the authors note, the term group selection has been criticized for implying that selection favors certain populations at the expense of others and that individuals forsake their own well-being for that of the community. Yet it is a well-known fact that selection at the individual level usually prevails. Part of the dramatic tension--and the cleverness--of their story lies in the way it addresses this central question: why doesn't selection between entities at a lower level disrupt integration at a higher level?

We see this conflict played out right from the beginning, with the first replicating molecules--jots of RNA (and initially there was no division between molecules that store and transmit information [DNA] and those that catalyze reactions [RNA]). While there was no reason to expect cooperation between these independently replicating jots, such interactions might have arisen randomly. For example, if one molecule's rate of replication came to depend on that of another, a primitive cooperative network could have been set up. Chance mutations--making one molecule a better replicase and another a better...