Neanderthals and sex

March 9, 2009 • 12:10 am

by Greg Mayer

A couple of news items from the past month deserve a quick comment or two. First, at the American Association for the Advancement of Science annual meeting in Chicago last month, Svante Paabo of the Max Planck Institute announced the completion of a draft genome for Neanderthal man, and that it indicated that modern man and Neanderthal man did not interbreed: the Neanderthals are our evolutionary cousins, not members of our own species.  The work by Paabo on the Neanderthal genome, and on ancient DNA in general, is fabulous, but two caveats must be noted: the first draft covers only 63% of the genome; and, most of the DNA comes from one cave in Croatia. So what you can say is in the 63% of the DNA they’ve looked at there’s no sign of interbreeding at this location. But we know secondary contact of differentiated populations in ice age Europe can be very complex; e.g. hooded crows would show evidence of interbreeding with carrion crows if sampled in some places but not others, so the case isn’t closed. And a personal quibble: according to the BBC

The draft genome can give us clues to the genetic regions which make us “uniquely human”, Prof Paabo told BBC News.

Besides the usual need to realize that knowing the genome of “X” doesn’t mean we know what it is that makes “X” so “X-ian”, Paabo implies here that Neanderthals weren’t human.  But by any biologically coherent notion of human they were (hence Homo neanderthalensis). John Hawks (hat tip: Pharyngula) has an excellent discussion of all sorts of issues relating to the Neanderthal genome.

Second, John Long (who has a wonderful book on fish evolution) and two colleagues published a paper in Nature (abstract only) reporting internal fertilization and vivipary in a placoderm, a group of ancient fish. This is a wonderful discovery, showing again that Philip Skell doesn’t know what he’s talking about (Skell, you’ll recall, had said fossils “cannot reveal the details that made these amazing living organisms function”!!!). But the paper got twisted in media reports into these fish inventing sex.  The BBC headline said “Fish fossil clue to origin of sex“, while, even more inexcusably, the British Museum (Natural History) website had “Fish knew first about sex“. Sexual reproduction originated in bacteria, probably billions of years before these fish. These fish may be the earliest vertebrates with copulation with an intromittent organ (a penis or similar structure); such organs have evolved multiple times, including four times in the amniotes (reptiles, birds, mammals).  The price of journalism is eternal vigilance.

Forbes loses it again over evolution

February 24, 2009 • 2:01 pm

A few days ago I wrote a piece for Forbes online responding to the ignorant assertions of a physician, Dr. Michael Egnor, who maintained that there was no evidence for Darwinian evolution.  In response, I reiterated the tenets of Darwinism and then cited copious evidence, through links in my piece, for common ancestry, transitional forms, vestigial organs, and the origin of new, complex biochemical systems through natural selection.  I also took Forbes itself to task for soliciting the opinions of intelligent-design creationists such as Egnor to “balance” their coverage of the Darwin bicentennial.  To its credit, Forbes allowed me to publish pretty strong criticism of their “let’s give crackpots an equal say” policy.

Well, I take the credit back.  Forbes has now given yet another benighted individual the final say in the debate.   Meet Dr. Philip S. Skell and his anti-Darwinian views.  Skell, an emeritus professor of chemistry at Penn State University, has been retailing his creationism and, especially, his disdain for evolution for some time on the Web (see, for example, here or here).

The curious thing is that Skell’s piece is not, as it pretends to be, a critique of what I said in Forbes, but merely a repetition of the argument, which he has been making for years, that evolution is of no practical use for humanity and of no use to experimental biology:

I don’t think science has anything to fear from a free exchange of ideas between thoughtful proponents of different views. Moreover, there are a number of us in the scientific community who, while we appreciate Darwin’s contributions, think that the rhetorical approach of scientists such as Coyne unnecessarily polarizes public discussions and­–even more seriously­–overstates both the evidence for Darwin’s theory of historical biology and the benefits of Darwin’s theory to the actual practice of experimental science.

He demeans fossils, for example, as having no bearing on helping us understand how organisms function:

Experimental biology has dramatically increased our understanding of the intricate workings within living organisms that account for their survival, showing how they continue to function despite the myriad assaults on them from their environments. These advances in knowledge are attributable to the development of new methodologies and instruments, unimaginable in the preceding centuries, applied to the investigation of living organisms. Crucial to all fruitful experiments in biology is their design, for which Darwin’s and Wallace’s principles apparently provide no guidance.

Contrary to the beliefs of Professor Coyne and some other defenders of Darwin, these advances are not due to studies of an organism’s ancestors that are recovered from fossil deposits. Those rare artifacts–which have been preserved as fossils–are impressions in stones which, even when examined with the heroic efforts of paleontologists, cannot reveal the details that made these amazing living organisms function.

What?  What about the evidence that feathers arose as thermoregulatory devices, and possibly as sexual signals as well? What about the evidence that some dinosaurs were warm-blooded, or that human ancestors were bipedal before they evolved big brains?  What about the “details” of the fish-amphibian transitional form Tiktaalik that show how it was adapted to functioning in the water and, fortuitously, evolved traits that were to help it invade the land?

Skell goes on and on about how “experimental” science actually helps us understand stuff, while historical sciences like evolutionary biology are useless:

It is widely accepted that the growth of science and technology in the West, which accounts for the remarkable advances we enjoy today in medicine, agriculture, travel, communications, etc., coincided with the separation, several centuries ago, of the experimental sciences from the dominance of the other important fields of philosophy, metaphysics, theology and history.

Yet many popularizers of Darwin’s theory now claim that without the study of ancient biological history, our students will not be prepared to engage in the great variety of modern experimental activities expected of them. The public should view with profound alarm this unnecessary and misguided reintroduction of speculative historical, philosophical and religious ideas into the realms of experimental science.

Skell cannot help himself.  In his endless feedback loop, he says the same things over and over again–the same things he’s been saying for years:

The essence of the theory of evolution is the hypothesis that historical diversity is the consequence of natural selection acting on variations. Regardless of the verity it holds for explaining biohistory, it offers no help to the experimenter–who is concerned, for example, with the goal of finding or synthesizing a new antibiotic, or how it can disable a disease-producing organism, what dosages are required and which individuals will not tolerate it. Studying biohistory is, at best, an entertaining distraction from the goals of a working biologist.

Yes, Dr. Skell, the practical advantages of evolutionary biology, while real, are limited.  I myself have made this  point in a book review in Nature.  But does the only value of science lie in its ability to make us rich or cure our diseases?  Many of us disagree.  Is it useless to know about The Big Bang?  Or about how we evolved from our primate ancestors?  Science is a process of finding out things–of satisfying our curiosity about nature, and understanding where we came from.  Some of that has practical benefits, some has spiritual benefits, but all of it is useful.  I would hardly call pure research “an entertaining distraction from the goals of a working biologist,” unless Skell’s definition of a working biologist is “one who cures diseases” (which, by the way, would put Dr. Skell in the not-a-working-biologist class, since his accomplishments are in carbene chemistry).  Evolution is the best story in science–it tells us where we came from, and by “we” I mean all living species, not just humans.  And it is a true story, and a wonderful one.  Unravelling and telling that tale is not “an entertaining distraction,” but part of what it is to be human.

Finally, Skell makes a mistake that brands him indelibly as a tyro in evolution:

It is unseemly and scientifically unfruitful that a major focus in biology should have turned into a war–between those who hold that the history of those unique organisms is purely a matter of chance aggregation from the inorganic world and those who hold that the aggregation must have been designed for a purpose.

The last time I looked, evolution was far more than a process involving “chance aggregation from the inorganic world.”  It critically involved a non-chance process: natural selection.  And are we to blame evolutionists for the intelligent-design movement, as Skell seems to do? That is palpable nonsense.

What is more distressing than Skell’s nonsense, which after all he’s been spouting for years, is the fact that Forbes has given him the last word in this debate.  And not only that, but a word that fails to respond to anything I have said. What is going on over there?  If they’re going to solicit a creationist to respond to me, presumably they would want one who could address my substantive points, including the many links I gave for the evidence for evolution. I said absolutely nothing about the usefulness of evolution to the material welfare of humans.  I did write the Forbes editor (who alerted me to Skell’s post) asking why it was published, and received no reply.   Apparently we can write off Forbes as a voice for reason.