Darwin missed a chance

We all know that Darwin missed at least one important finding during his lifetime: the work of Gregor Mendel.  It’s unlikely that he actually knew of it, or that he would have appreciated its significance if he had (it would have solved the dilemma, pointed out by the engineer Fleeming Jenkin, that Darwin’s own theory of blending inheritance inexorably erodes the genetic variation necessary for natural selection to work), but the lack of a Darwin-Mendel conjunction is often mourned by evolutionists.  Now a trio of scholars have found another “missed opportunity” for the Sage of Downe.

In a new communication to Current Biology, Adam Hart et al. report the discovery of a letter written to Darwin by the British entomologist Albert Brydges Farn (1841-1921).  Farn lays out in his letter the evidence that color variation and change in the moth Gnophos (now Charissa) obscurata, called the “annulet,” reflected the action of natural selection.  It’s the peppered-moth story in a different species.  Had Darwin followed this up, say Hart et al., he would have apprehended a crucial piece of evidence missing from his theory: observation of natural selection in action.  Here’s Farn’s letter, sent to Darwin on November 18, 1878.

My dear Sir,
The belief that I am about to relate something which may be of interest to you, must be my excuse for troubling you with a letter.

Perhaps among the whole of the British Lepidoptera, no species varies more, according to the locality in which it is found, than does that Geometer, Gnophos obscurata. They are almost black on the New Forest peat; grey on limestone; almost white on the chalk near Lewes; and brown on clay, and on the red soil of Herefordshire.

Do these variations point to the “survival of the fittest”? I think so. It was, therefore, with some surprise that I took specimens as dark as any of those in the New Forest on a chalk slope; and I have pondered for a solution. Can this
be it?

It is a curious fact, in connexion with these dark specimens, that for the last quarter of a century the chalk slope, on which they occur, has been swept by volumes of black smoke from some lime-kilns situated at the bottom: the herbage, although growing luxuriantly, is blackened by it.

I am told, too, that the very light specimens are now much less common at Lewes than formerly, and that, for some few years, lime-kilns have been in use there.

These are the facts I desire to bring to your notice.

I am, Dear Sir, Yours very faithfully,

A. B. Farn

In fact, the idea of industrial melanism as evidence for natural selection was not explicitly suggested until 1896 (14 years after Darwin’s death) by the British entomologist James William Tutt.

There’s no evidence that Darwin answered Farn’s letter, but of course he had voluminous correspondence with hundreds of people, and it’s too much to fault the old man for failing to follow up on this one suggestion.  And even had he done so, that might not have hastened the general acceptance of natural selection, which after all was not widely embraced by evolutionists until around 1930.  Nevertheless, it’s interesting to contemplate Darwin’s reaction as he read this letter.  Did he blow it off? Or did it simply get lost in the welter of his correspondence?

Hart et al. imply that this is the one crucial missing link in Darwin’s “chain of evidence,” but of course there’s another: the fossil record.  Archaeopteryx, a transitional fossil spanning reptiles and birds, was known in Darwin’s time—and he even mentions it in a later edition of The Origin*—but he didn’t seem to have grasped its significance. However, the evidence for common ancestry that could have been provided by Archaeopteryx was also supplied by several other areas of biology, notably embryology and the study of vestigial features.

Fig. 1.  The annulet, Charissa obscurata. Looks a lot like Biston betularia, no?

*p. 367 of the fourth edition: “Until quite recently these authors might have maintained, and some have maintained, that the whole class of birds came suddenly into existence during the eocene period; but now we know, on the authority of Professor Owen, that a bird certainly lived during the deposition of the upper greensand; and still more recently, that strange bird, the Archeopteryx, with a long lizard-like tail, bearing a pair of feathers on each joint, and with its wings furnished with two free claws, has been discovered in the oolitic slates of Solenhofen. Hardly any recent discovery shows more forcibly than this how little we as yet know of the former inhabitants of the world.”

____

Hart, A. G. R. Stafford, and A. E. Goodenough. 2010. Evidence for contemporary evolution during Darwin’s lifetime. Current Biology 20:R95.

h/t: Matthew Cobb

The Apocalypse: $8 for an airline blanket

Okay, once in a while I get to gripe about stuff that doesn’t involve either evolution or religion.

This is a bad one.  The New York Times “In Transit” website (via Joesentme.com) announced that, as of May 1, passengers on flights longer than two hours will have to pay for blankets and pillows:

American Airlines quietly announced last week that it would eliminate free blankets in coach and sell an $8 packet that includes a pillow and blanket starting May 1. . .

The change is for flights over two hours in length to and from Canada, Mexico, Hawaii, the Caribbean and Central America. The airline will join JetBlue and US Airways, which began charging $7 for a pillow-and-blanket set in 2008 and 2009 respectively.

(Note that they announced this “quietly”!)

Enough is enough. I’ve watched while American (and most airlines other than Southwest) started charging for baggage and any food more substantive than a bag of pretzels.  The planes have gotten dirtier and more unkempt (on my last American transAtlantic flight, my back-seat video and audio weren’t working, and the plane was too full to change seats), and the food has gone from mediocre to inedible.  But this—the gouging of passengers for an EIGHT DOLLAR BLANKET—is nothing more than a money-grubbing insult.

You can file a complaint here.

_______

Bonus: If you want to see what the cabin crew say to each other on their communal website, go here.  (A fun thread is “celebrity sightings”, where flight attendants recount their experiences with famous passengers. Sample: “Jennifer Lopez: I CANNOT STAND THIS WOMAN…she yelled at me because I couldn’t make her a double espresso, and then told me that my shoes looked cheap!!!!!! can you believe it!? so I replied “well at least they match YOUR bag!”)

Apropos Drs. Fodor and Piattelli-Palmarini

h/t: Occam and, of course, xkcd

To quote Davy Crockett:  “Be always sure you’re right—then go ahead.”

Darwin Day in Wisconsin

by Greg Mayer

The Darwin bicentennial year ends this week, as Friday, February 12th, begins the 201st year. The last event in the University of Wisconsin-Parkside’s Darwin 1809-1859-2009 commemoration is this coming Wednesday, Feb. 10, at 7 PM in Greenquist Hall 103, where I will be speaking on “The Origin of The Origin“.

In the talk, I’ll take a look at the surprisingly dramatic circumstances of the publication of The Origin on November 24, 1859.  In the spring of 1858, while at work on his “species book”, Darwin received a manuscript from Alfred Russel Wallace, a correspondent of his working in the Malay Archipelago. In Wallace’s manuscript, Darwin saw his own theory in miniature, and despaired that his originality would be forestalled. Darwins’ friends Charles Lyell and J.D. Hooker arranged for a joint publication by Darwin and Wallace; Darwin, now spurred on, completed an “abstract” of his species book: the Origin, which, at 500 pages, was a rather substantial abstract. (Jerry was an earlier speaker in the series; video here.)

On Saturday, the 201st anniversary year gets off to a bang with the University of Wisconsin, Madison’s annual Darwin Day. There’ll be a full day of activities, headlined by my friend and colleague Jonathan Losos, who’ll speak on “Leaping Lizards!  Studies of Ecology and Evolution in the Caribbean”. Over the lunch break there’s a workshop for teachers on lizards and island biogeography, and I’ll be participating. In the afternoon, there’ll be a panel discussion on communicating science, which might be of some interest to WEIT blog readers.

Both events are intended for general audiences, and are free and open to the public. If you’re in the area, please come. Details of both events, including schedules and directions, are here for Parkside (in Kenosha, just north of Illinois) and here for Madison.

Amazing hunting behavior of killer whales

I’m reading a new book on biogeography, Here Be Dragons, by Dennis McCarthy.  It’s a popular-science introduction to the field, designed to show how evolution, along with plate tectonics and other changes in the configuration of land and sea, can explain the puzzling distributions of plants and animals on our planet. It’s worth a read, though a bit light on data and sometimes purplish in the prose.

Anyway, McCarthy mentions an amazing hunting behavior of orcas (Orcinus orca, also called killer whales), and gives a YouTube URL for the behavior.  I’ve put the video below.  Here you see a group of orcas pursuing a seal who’s taken refuge on an ice floe.  The whales band together and head toward the floe, creating a bow wave that washes the seal into the water, ready for consumption.  This video, however, has a happy ending:

Don’t pick on the moderates!

. . . say Jesus ‘n’ Mo.

Colored dinosaurs: Part II

I recently posted about the discovery of pigment granules in a fossil feathered theropod dinosaur—the same type of pigment granules found in fossil early birds as well as modern birds.  This similarity not only strengthened the evolutionary argument that birds are the modern descendants of theropods, but also enabled scientists to crudely reconstruct the feathered dino’s color.

A related paper has just been published in Science, showing even better fossilization of the melanosomes and thus giving a better idea of the color and pattern of those dinos. The animal is Anchiornis huxleyi, a small (woodpecker-sized) feathered dinosaur from the late Jurassic, about 150 million years ago.  This nonflying theropod was pretty highly feathered, and those fossil feathers also contained fossil melanosomes.  Comparing the size and shape of the fossil melanosomes with those of melanosomes in modern birds, the authors were able to make educated guesses about whether the  granules contained red, gray, or black pigments.

Here’s their conclusion:

In summary Anchiornis huxleyi was darkly colored with gray and black body plumage (Fig. 4). The head was gray and mottled with rufous and black. Elongate gray feathers on the front and sides of the crest appear to frame a longer rufous hindcrown. Gray marginal wing coverts formed a dark epaulet that contrasted strongly with the black/gray-span light primaries, secondaries, and greater coverts of the forelimb. The large black spangles of the primaries and secondaries created a dark outline to the trailing edge of forelimb plumage. The spangles of the outer-most primaries were black. The greater coverts of the upper wing were spangled with gray or black, creating an array (secondary coverts) or rows (primary coverts) of conspicuous dots. The contour feathers of legs were gray on the shank, and black on the foot. Like the forelimb, the elongate feathers of the lateroplantar surface of the hind limb were white at their bases with broad black distal spangles.

I have only one comment on the paper.  At the end, the authors say this: “Thus, the first evidence for plumage color patterns in a feathered non-avian dinosaur suggests selection for signaling function may be as important as aerodynamics in the early evolution of feathers.” (The National Geographic website—see below—makes a similar suggestion.)  It seems to me that neither signaling nor aerodynamics can explain the early origin of feathers, if for no other reason that you can’t select for colored feathers until you first have feathers, and because early feathers—the filamentous structures on some feathered dinos—could hardly have had an aerodynamic function.  What seems more likely is that the origin of feathers involved some other selection pressure—perhaps a thermoregulatory one—and then those early feathers gave rise to the possibility that they could, via pigmentation, be used for intraspecific signalling.  Then, later, they could be coopted for flight.  In other words, flying and signaling are exaptations of a feature that originated for some other reason.

Here’s an artist’s reconstruction of the beast:

Fig. 1.  (Fig. 4 from Science paper): Reconstruction of the plumage color of the Jurassic troodontid Anchiornis huxleyi.   Color plate by Michael A. Digiorgio.

Looks a bit like this, no?

Fig. 2.  The roadrunner, Geococcyx californianus

The National Geographic website has more detail on this discovery, along with an animated 3-D reconstruction of A. huxleyi.

Greg has jogged my memory by reminding me that Anchiornis is very important in showing that feathered dinos actually preceded Archaeopteryx (a transitional form that might have flown).  I posted about this issue a while back, and quote Greg’s email here:

The Science paper actually says a lot more about dinosaur color than the Nature paper, but it’s drawing less attention because it’s coming out a few weeks later (the Science people also did the original work on fossilized melanosomes). One really interesting bit about this is that Anchiornis is the first feathered dinosaur that is older than Archaeopteryx, thus solving the “temporal paradox” which was one of the chief arguments used against dino-bird ancestry. This has only been known for a few months, and I did not see much about it at the time, but i think it’s actually more important (as opposed to astonishingly mind-blowing) than the colors. See here and here.

________________

Li, Q. et al. 2009.  Plumage color paterns of an extinct dinosaur.  Science (Sciencexpress online).

h/t: Carl Zimmer, Greg Mayer

Freethought Radio podcast

A while back I was scheduled for an interview on Air America, the all-liberal network that, sadly, went belly-up.  The interview went on, but was broadcast as part of Freethought Radio out of Madison, Wisconsin.  My conversation was with Dan Barker, author of Godless (a book that all atheists should read) and his wife, Annie Laurie Gaylor, and you can find the podcast here.  My part starts about halfway in.

New Scientist blurbs dumb ideas about evolution

Ah, New Scientist always jumps gleefully on any idea that combines the words “Darwin” and “wrong.”  Remember their “Darwin was wrong” cover a year ago?  Well, they’ve befouled themselves again, this time by publishing, without any critical comment, a piece by Jerry Fodor and Massimo Piattelli-Palmarini that is a precis of their upcoming book, What Darwin Got Wrong.  I’ve intimated before that this book is not exactly God’s gift to the scientific literature, and will save my comments for an upcoming review. But if you want to see the gist of their argument without having to waste $$ on their book, the New Scientist article is the place to go.  Fodor and Piattelli-Palmarini’s beef: natural selection, which they find logically flawed and empirically unsupported.
Their conclusion:

However, the internal evidence to back this imperialistic selectionism strikes us as very thin. Its credibility depends largely on the reflected glamour of natural selection which biology proper is said to legitimise. Accordingly, if natural selection disappears from biology, its offshoots in other fields seem likely to disappear as well. This is an outcome much to be desired since, more often than not, these offshoots have proved to be not just post hoc but ad hoc, crude, reductionist, scientistic rather than scientific, shamelessly self-congratulatory, and so wanting in detail that they are bound to accommodate the data, however that data may turn out. So it really does matter whether natural selection is true.

Fodor, at least, has made a career out of this kind of rhetoric, but as you’ll see from my forthcoming review (and already saw from my critique of his ideas in The London Review of Books), this time his rhetoric is like that of the Wizard of Oz: he’s the little man behind the curtain with a big voice but not much insight.

Read the comments, too—there are lots of them, nearly all critical.  This is only the beginning of the drubbing that Fodor and Piattelli-Palmarini should expect when their book is judged by scientists and philosophers.

Oh, and shame on New Scientist for printing such misguided puffery.  What’s next—articles by Ken Ham and Bill Dembski?

Richard Dawkins on Bill Hamilton

If you’re not an evolutionary biologist, or don’t know of Bill Hamilton, you can ignore this post, but if you recognize the name it’s worth listening to this 25-minute audio cliip from a recent BBC program.  In it, Richard Dawkins discusses and praises his late colleague, the brilliant and eccentric biologist William Hamilton. Mary Bliss, Hamilton’s sister, also chimes in.  I won’t describe Hamilton’s many achievements (and quirks) here, as Dawkins and Bliss do that very well.

h/t: Matthew Cobb