Saturday, August 18, 2007

Evolution: A Great Mystery?

Live Science , an online science news portal is carrying out a "greatest mystery" series, in which they are asking prominent scientists from various fields to talk about the unknowns. With a series title like this, it is inevitable that the chosen scientist and the reporter will play up the 'mystery' part and give the impression that scientists are pretty much befuddled. For the theory of evolution , the scientist interviewed (Aug 16 2007) was Massimo Pigliucci of the Department of Ecology and Evolution at Stony Brook University in New York. T. Ryan Gregory has dissected the interview in his blog and pointed out the various misunderstandings that it created regarding the state of our understanding about evolution. I will add just one more impression. The interviewer writing about various evolutionary "forces" says

Self-organization is another evolutionary force that some experts say whips up complex features or behaviors spontaneously in living and non-living matter, and these traits are passed on to offspring through the generations.

"A classic example outside of biology are hurricanes: These are not random air movements at all, but highly organized atmospheric structures that arise spontaneously given the appropriate environmental conditions," Pigliucci said. "There is increasing evidence that living organisms generate some of their complexity during development in an analogous manner."

The example given of a spontaneously arising complex structure is protein folding. Proteins take on endless shapes and the mechanism that triggers this form is a chemical signal.

I have always felt that reports like these neglect to explain the distinction between proximate causes and ultimate causes. Proteins do fold spontaneously, but proteins serving a particular function always fold the same way. So in trillions of cells in trillions of different organisms, something is controlling the consistency of the chemical signal and therefore the shape the protein. That something is the gene(s) that codes for the signal. Which means that over time evolution has populated the world with only those genes that code for just the right chemical signal. The process that causes such an accumulation of the right genes is natural selection.

Biologist may not today understand the mechanics of protein folding (proximal causes), but they accept that natural selection has to be the ultimate cause. In this case I feel Massimo Pigliucci fudged the part of ultimate causation and exaggerated the mystery of proximate causation. The level at which such apparent mysteries exists needs to be clarified by the interviewed scientist. It would be too much to expect from the media.

1 comment:

  1. I think you have made a valid point there. The media should really take a more profound interest on the scientists thought that they are interviewing reather than look at the more appealing "Mystery" scenario