May 10, 2005

Darwinian evolution is so over

No, I'm not talking about the hearings in Kansas. The topic is Freeman Dyson's article "The Darwinian Interlude" in the March issue of Technology Review, which I just got around to reading yesterday.

Dyson's idea is that the first period of life on earth was a sort of bacterial version of primitive communism,

a golden age of pre-Darwinian life, during which horizontal gene transfer was universal and separate species did not exist. Life was then a community of cells of various kinds, sharing their genetic information so that clever chemical tricks and catalytic processes invented by one creature could be inherited by all of them.

Then, Dyson writes,

one evil day, a cell resembling a primitive bacterium happened to find itself one jump ahead of its neighbors in efficiency. That cell separated itself from the community and refused to share. Its offspring became the first species. With its superior efficiency, it continued to prosper and to evolve separately.

With individualism came sex -- negotiated bilateral genetic commerce -- and hierarchy -- structured multicellular organisms -- and "brains, which opened a new world of coördinated sensation and action, culminating in the evolution of eyes and hands". And now, those brains have allowed us to return to genetic communism:

[T]he Darwinian era is over. The epoch of species competition came to an end about 10 thousand years ago when a single species, Homo sapiens, began to dominate and reorganize the biosphere. Since that time, cultural evolution has replaced biological evolution as the driving force of change. Cultural evolution is not Darwinian. Cultures spread by horizontal transfer of ideas more than by genetic inheritance. Cultural evolution is running a thousand times faster than Darwinian evolution, taking us into a new era of cultural interdependence that we call globalization. And now, in the last 30 years, Homo sapiens has revived the ancient pre-Darwinian practice of horizontal gene transfer, moving genes easily from microbes to plants and animals, blurring the boundaries between species. We are moving rapidly into the post-Darwinian era, when species will no longer exist, and the evolution of life will again be communal.

In other words, Intelligent Design starts here? Not everyone is confident that the human designers will be intelligent enough; and presumably nature will continue to act and react; but maybe the Kansas state board of ed should call Dyson to testify. Though somehow, I don't think his brand of anti-Darwinism is quite what they're looking for.

Anyhow, it's curious how people like to force scientific theories into the shape of political metaphors. I guess Dyson's little bio-marxist riff is a fair reaction to a hundred and fifty years of social darwinism.

Dyson is taking off from Carl Woese's "A New Biology for a New Century", Microbiology and Molecular Biology Reviews 68(2) pp. 1092-2172. Woese's thesis is not anti-Darwinian, but rather anti-reductionist, or maybe post-reductionist:

Biology today is at a crossroads. The molecular paradigm, which so successfully guided the discipline throughout most of the 20th century, is no longer a reliable guide. Its vision of biology now realized, the molecular paradigm has run its course. Biology, therefore, has a choice to make, between the comfortable path of continuing to follow molecular biology's lead or the more invigorating one of seeking a new and inspiring vision of the living world, one that addresses the major problems in biology that 20th century biology, molecular biology, could not handle and, so, avoided. The former course, though highly productive, is certain to turn biology into an engineering discipline. The latter holds the promise of making biology an even more fundamental science, one that, along with physics, probes and defines the nature of reality. This is a choice between a biology that solely does society's bidding and a biology that is society's teacher.

Dyson's bio-marxism is his own overlay on Woese, who doesn't stress any similar rhetorical opposition of communal vs. individual in his article, though he does suggest that there was a "Darwinian threshold or Darwinian transition" which "took the cell out of its initial primitive state in which HGT [Horizontal Gene Transfer] dominated the evolutionary dynamic (and evolving cells had no stable genealogical records and evolution was communal) to a more advanced (modern) form (where vertical inheritance came to dominate and stable organismal lineages could exist)." Woese draws the lesson that we should "hold classical evolutionary concepts up to the light of reason and modern evidence before weaving an evolutionary tapestry around them. Most of them will turn out to be fluid conjectures that 19th century biologists used to stimulate their thinking, but conjectures that have now, with repetition over time, become chiseled in stone: modern concepts of cellular evolution are effectively petrified versions of 19th century speculations." And he concludes that

The molecular cup is now empty. The time has come to replace the purely reductionist "eyes-down" molecular perspective with a new and genuinely holistic, "eyes-up," view of the living world, one whose primary focus is on evolution, emergence, and biology's innate complexity. (Note that this does not mean that the problems worked on in any new representation of biology will not be addressed by customary molecular methodology; it is just that they will no longer be defined from molecular biology's procrustean reductionist perspective.) [emphasis added]

Though this may be a minority view within biology -- just as molecular biology perceived itself as an embattled minory in 1963, when I had a summer job in a molecular biology lab -- it's by no means an isolated or heretical perspective. I recently heard a form of this same message from David Searls, SVP Worldwide Bioinformatics at GSK, in his presentation at a symposium on Formal Grammars, DNA and Linguistic Theory. David suggested, in effect, that we now understand the biological equivalents of phonology, morphology, syntax and even semantics, and therefore are ready to face the challenge of understanding whole biological "discourses" in organisms, ecologies and societies.

Posted by Mark Liberman at May 10, 2005 11:23 AM