Wednesday, July 28, 2010

Getting past evolutionary pointilism--or creationism in the journal Nature?

The July 15 issue of Nature, in true Nature style, has a high human-interest picture of a fossil cranium fragment (glaring at you from the cover!) that purportedly shows that the separation between ancestors of Old World monkeys and apes had occurred. The find was in Saudi Arabia, and while Holly is the person most appropriate to discuss the details, we have a few words to say about it until she does.

The fossil is about 29 million years old. It does not have a specific trait found only in modern Old World monkeys, but not in apes. If the interpretation is correct, and we have no reason to question it based on our own fragmentary knowledge of this area, then it does suggest that the monkey-ape divergence occurred subsequent to when this individual lived.

Fine. Our issue, and it's yet another complaint about Nature's drive to be a pop-culture rather than serious scientific journal, is with the heading: " Parting of the Ways: Saudi Arabian fossil pinpoints divergence of Old World monkeys."

The implication in Nature is almost creationist in nature. It is the assumption that this lump of one-time bone was at the 'parting' of the ways, and that such events occur instantaneously. If not, how could a specimen 'pinpoint' the separation?

In fact, speciation is a gradual, statistical, probabilistic population phenomenon. It does not generally occur in a moment.

But suppose this is science, not Creationism on Nature's part. Even then, what is the chance that this particular specimen, or even any specimen from thousands of square kilometers or thousands of generations around this time, was the 'point' of speciation? The odds are minuscule, and in a deeper sense untestable.

Speciation, in the usual definition, would be the time at which no individual from either of the two new-lineage populations could successfully mate. But for thousands of generations, gradual divergence would in reality merely have diminished the probability that a random male from one and female from the other ancestral population could have mated successfully.

Even a mutation that by itself would make such mating impossible would not have spread throughout one of the populations so that the two species lineages were suddenly discrete and immiscible.

To melodramatize speciation and evolution in a way that almost makes it creationistic is yet another editorial decision by the journal that shows either crass grabbing for sales, the superficial understanding of science even by scientists or science journalists, or the simple dumbing down of science. The last thing it is, is a contribution to evolutionary science (we note that this is the editors' fault, not the authors: their paper makes none of these idiotic claims. Instead, they say that the fossil record may now show that the split happened during a 5 million year period after the demise of this current individual).


occamseraser said...

Do the authors of the featured scientific article itself make the "point" in time claim you complain about from the poorly worded headline?
I think not. Worry more about content and whine less about Nature covers and headlines! I'm starting to worry about your ability to be objective when it comes to Nature.

Anne Buchanan said...

Indeed, OE, we thought of you when writing this post. Thus, the subsequent post.

Ken Weiss said...

I'm not sure what Anne means 'subsequent', but in this post we finish by (I thought) clearly saying that this was not a problem in the paper, nor by the authors, but by the editorial staff.

We 'whine' because the public, and I believe many or even most evolutionary biologists, and certainly a lot of parigeneticists (human biomedical, bioinformatic, epidemiological, etc.) widely express such simplistic views. Not thinking in population or evolutionary terms is common and, I think, should be corrected and resisted.

We read and subscribe to Nature, so what it means to be 'objective' is debatable. We try to find good science stories, and to point out bad aspects. There are plenty of hyperbolists, but far too few trying to apply a critical (in the proper sense of 'evaluative') eye, I think.

Anne Buchanan said...

I meant our July 29 post taking on the New England Journal of Medicine. It's not just Nature we take to task.

oe said...

...but "creationism"? C'mon.
Nice MT headline, misleading but eye-catching. Oh, wait, it's a joke, right? hahahaha

Ken Weiss said...

Well, yes, of course a joke....except that perpetuating any kind of event rather than process view of species formation is misleading and in today's day and age should not occur among scientists, at least. And that kind of misleading interpretation isn't a joke.

Of course, in today's day and age, with the ugly and benighted kind of creationism around, one has to be careful even about jokes, I guess.