What frogs go through for their tadpoles

September 4, 2009 • 2:30 pm

by Greg Mayer

Matthew has once again given me a hot tip: the BBC has a video of a mountain chicken, Leptodactylus fallax, feeding its developing tadpoles with unfertilized eggs. (I am unable to embed the video– do click through to watch). The mountain chicken is actually a large frog (so named because they are good eating– many years ago an attempt was made to establish the species in Puerto Rico as a food source) that is found on the eastern Caribbean islands of Montserrat and Dominica, and formerly Martinique.

Leptodactylus melanonotus, a smaller relative of the mountain chicken

Feeding unfertilized eggs to tadpoles may seem like a bizarre and exotic way to take care of your offspring (the BBC labeled it an “alien scene”), but it’s actually sort of mundane in the world of amphibians. Amphibians have the most diverse set of modes of reproduction and nutrition of juveniles of all the land vertebrates. Laurie Vitt and Janalee Caldwell, in their superb herpetology textbook, list 40 different reproductive modes for frogs. Its hard to pick a strangest amphibian reproductive mode, but I’d go with either the gastric-brooding frog, Rheobatrachus silus, in which the female swallows her eggs, which develop in her stomach, or histophagy, practiced by several amphibians, in which the fetuses feed upon the mother’s hypertrophied oviductal lining (i.e. while still inside of her).

Dendrobates auratus with tadpole, Est. Biol. La Suerte, Costa Rica

The poison dart frog, Dendrobates auratus, above is a male, carrying a single tadpole in the lower middle of its back, which it will transport to some wet spot, such as a puddle or tree hole. The female of its relative Dendrobatus pumilio (featured in a previous post) places its tadpoles in the axils of bromeliads or other arboreal plants, and then returns, like the mountain chicken, to feed them with unfertilized eggs.

DSCN3789The pair of tree frogs, Hyla phlebodes, above was found in amplexus (that’s what mating is called in frogs); the male is the smaller one. Unlike the other frogs mentioned in this post, this species has the typical, un-exotic reproductive mode for frogs: eggs are laid in the water, which hatch into tadpoles, which metamorphose into froglets. It’s a pretty wondrous way of life, too, it just seems a bit un-exotic because we’ve been jaded by its familiarity.

Many amphibians have recently undergone significant population declines, and a number of species, including the gastric-brooding frog are now extinct. A fungal disease called chytridiomycosis has been implicated in causing the decline of many species, including the mountain chicken. The BBC video was made as part of a captive breeding conservation effort involving the Jersey Zoo, founded by the late naturalist and author Gerald Durrell,and the London Zoo.

Worst paper of the year?

September 4, 2009 • 6:00 am

A new paper in the Proceedings of the National Academy of Sciencee makes the bizarre and completely unsupported claim that the two stages of the butterfly life cycle: caterpillar and volant adult, result from a hybridization event, with the caterpillar resulting from a butterfly mistakingly mating with an onycophoran (velvet worm). Instead of a single lineage evolving two different life stages, then, each stage reflects a completely independent evolutionary event.,

An article on this paper in Scientific American first explicates the theory:

In the current issue of Proceedings of the National Academy of Sciences (PNAS), Donald Williamson, a wheelchair-bound 87-year-old zoologist from the University of Liverpool in England, suggests that the ancestors of modern butterflies mistakenly fertilized their eggs with sperm from velvet worms, also known as onychophorans. “People have been trying to find one solution that covers all of metamorphosis,” Williamson says. “I say it’s a change in taxon during development.”

Velvet worms, which fall between worms and insects on the tree of life, have soft-bodies and superficially resemble caterpillars, particularly the larvae of an early butterfly relative known as Micropterix. Velvet worms have evolved a variety of elaborate fertilization procedures. Males are known to place sperm packets not on the female’s genital opening, but rather on skin tissue, which the sperm penetrates before migrating to the ovaries.

Williamson believes that an ancient insect accidentally picked up that sperm, and butterflies now contain two developmental programs so they live half their life as velvet worms and half their life as winged butterflies.

“Animals have been able to hybridize since they invented sex,” Williamson says. “With external fertilization, there’s always the possibility that some sperm will fertilize the wrong egg.”

and then gathers the reaction of other scientists, which is uniformly negative:

However, scientists asked to comment on Williamson’s theory were taken back by it and surprised it made it into such a prestigious journal. For example, from insect paleontologist Conrad Labandeira of the Smithsonian National Museum of Natural History in Washington, D.C.: “You’re kidding!”

After looking over the paper, Labandeira pointed out more substantial criticisms. Hybridization between closely related species sometimes occurs in the animal kingdom, but it is highly unlikely that the sperm of a velvet worm could fertilize a distantly related insect egg and produce a viable embryo. He also raises the question of where the genetic program controlling metamorphosis would come from.

“If I was reviewing [this paper] I would probably opt to reject it,” he says, “but I’m not saying it’s a bad thing that this is published. What it may do is broaden the discussion on how metamorphosis works and…[on]…the origin of these very radical life cycles.”

Insect developmental biologist Fred Nijhout of Duke University took a less diplomatic view of the article saying it would be better suited for the “National Enquirer than the National Academy.

Besides being inherently implausible, the theory can be easily refuted by DNA analysis, which should show, in butterflies, two completely disparate genomes, one resembling that of onycophorans.

Now who communicated this bizarre, unsupportable paper to one of the world’s most prestigious journals? Think about it: who has made their careeer asserting that all of evolution results from lateral gene transfer and hybridization?

Lynn Margulis.

Margulis had some great ideas early in her carreer, most famously the bacterial endosymbiont idea of the origin of mitochondria. She’s deservedly famous for pushing those ideas in the face of serious doubt. But lately she’s been spreading bizarre ideas about hybridogenesis being the main driver of evolution.(I was particulary distressed by the book on speciation she wrote with her son Dorian Sagan — also son of Carl Sagan, to whom Margulis was married — Acquiring Genomes: A Theory of the Origins of Species [2002], which argued that hybridization is a pre-eminent driver of speciation. Fortunately, the book has had zero impact on the field of speciation.)

Margulis is showing symptoms of what I call the Big Idea Syndrome, to wit: “Whatever I study is the most important thing in evolution — in fact, the driving force of evolution.” We’ve seen it before with developmental plasticity, epigenesis,evo devo, and other such buzz-fields. It’s all too tempting to think that one’s pet idea applies widely, or even universally.

PNAS of course, permits elected members of the Academy to promote papers they like by “communicating” them and adjudicating the reviews, which were often solicited by friends of the member or those known to be favorable to a paper’s results. This has resulted in the journal’s publication of some egregious work on the past; Linus Pauling’s papers on vitamin C are the most famous example.

Fortunately, this situation is changing, and soon PNAS manuscripts will receive the same rigorous review as regular journals offer — and bigwigs will no longer be able to push substandard work into publication.

____________

Williamson, D. I. 2009. Caterpillars evolved from onycophorans by hybridogenesis. Proc. Nat. Acad. Sci. Early Edition (online)

In ‘bama

September 3, 2009 • 3:59 pm

Awash in the Crimson Tide, I’ve made it, and am about to have a genteel Southern dinner (at the riverside Cypress Inn — they have peanut butter pie!) before my talk. Tomorrow: grits and red-eye gravy — and hopefully biscuits — for breakfast, and ribs for dinner.

The campus here is lovely, and large, with the huge Bryant-Denny football stadium (now being enlarged to contain 101,000 seats!) looming above it all. Nearby is Foster Auditorium, where George Wallace made his futile bid to prevent black students from enrolling on June 11, 1963 — an event that I’m old enough to remember. There’s a museum to Bear Bryant as well, whose statue (along with those of other championship-winning coaches) stands outside the stadium. Large fraternity houses line the main drag, and on the side streets are gorgeous houses, shaded by old oaks, which are said to be the purview of wealthier faculty members.

I’m told that Harper Lee, author of To Kill a Mockingbird, lives nearby, and can be seen going to the campus library from time to time. But one is advised not to approach her for a signature!

fb-stadiumFig. 1. The humongous Bryant-Denny stadium

But what most impressed me was the President’s house, cheek by jowl to the stadium. It’s said to be one of only two buildings on campus that weren’t razed by the Yankees at the end of the Civil War. Imagine living in a place like this — your own Tara!

100198-004-FF3499B3Fig. 2. President’s house, University of Alabama

And so to fuel up for the big evolution talk. . .

Post mortem: It’s always hard to tell from the inside how these things went, but I was very pleased. Despite a nagging bronchitis, I soldiered on about the evidence for evolution, and I think it went well. Lots of people showed up, the questions were intelligent and wide-ranging, and even my criticism of religion as a cause of anti-evolution sentiment was received well. (One person did say that my comments on religion might have been inimical to my message about evolution.)

And I sold a lot of books! I think the best gauge of audience reaction will be in the Tuscaloosa paper, or perhaps even on this website. All I can say is that everyone I’ve met — especially my hosts — has been friendly and (dare I use the word) accommodating. Bring on the biscuits!

Oh, and one more astounding fact: the head football coach at Alabama makes four million dollars per year!

Arab organization prosecuted for anti-Semitic cartoon

September 3, 2009 • 6:12 am

No religion should be immune to public criticism.  Now that the Danish cartoon scandal has nearly blown over, the Dutch government is prosecuting the Arab European League for publishing a cartoon depicting Holocaust denial.

The cartoon shows two apparently Jewish men standing near a pile of skeletons with a sign that says “Auswitch,” presumably representing the largest Nazi concentration camp, Auschwitz.

One pokes a bone with a stick and says “I don’t think they’re Jews” and the other answers, “We have to get to the six million somehow.”

Ronny Naftaniel of the Center for Documentation on Israel, which filed a complaint against the cartoon, said Jews had nothing to do with the Muhammad cartoons, so it didn’t make sense for the league to retaliate in this way.

“Imagine if Dutch Jews insulted Muslims every time they heard an anti-Semitic remark. What kind of perverse world would we be living in?” he said.

Judging from its website, the AEL does seem like an invidious organization, and yes, “hate speech” is a crime in the Netherlands (indeed, Holocaust denial is a crime in Canada), but the proper response to hate speech is not censorship, but anti-hate speech.  My own view is that Holocaust denial should be protected free speech, and the way to deal with it, as Michael Shermer did in Why People Believe Weird Things, is to expose the lie and debunk it with the facts.

Here’s the cartoon at issue:

ae-league03
So far this cartoon hasn’t inspired the spate of riots and murders that followed publication of the anti-Islamic Danish cartoons.

Annoy.com has the complete set of the Danish cartoons, as well as five other controversial cartoons published by the Arab European League (right-hand column, scroll down).

I’m off to Alabama

September 2, 2009 • 2:42 pm

. . .with my laptop on my knee.  The good folks at UA Tuscaloosa* invited me down to give two talks: one a lecture to the general public on the evidence for evolution, the other a departmental seminar on speciation in flies (my day job).  I’m donning Kevlar for the former: an announcement of my talk in the Tuscaloosa News has already spawned six pages of heated comments, much of it worried about whether I’ll spread atheism along with biology.

As is my habit (“will lecture for food”), I’ve asked to sample the indigenous culinary delights, said to include ribs at Dreamland (and I’m quite partial to banana pudding).  Now if they can just dig up a decent meat-and-three place. . .

In the meantime, until Saturday pm, Greg Mayer and/or Matthew Cobb will be filling in for me.

1204837655_6745Fig. 1.  Ribs at Dreamland.  Do they match Chicago’s best?

_____

*From the Tuscaloosa Convention and Visitor’s Bureau web page: Tuscaloosa was the source of a joke in the 1931 Marx brothers film “Animal Crackers.” Groucho Marx discusses shooting an elephant and attempting to remove the tusks. “Of course in Alabama the Tusc-a-loosa, but that is totally irrelephant to what I was saying,” he quipped.

James Wood replies

September 2, 2009 • 8:55 am

In the August 31 issue of The New Yorker, James Wood, an eminent literary critic based at Harvard, wrote an article (“God in the Quad”) taking to task not only the “new atheists,” but also several of their critics, most notably Terry Eagleton.

Within a day I put up an analysis of Wood’s piece on this website; my main point was that he espoused a middle-of-the-roadism that would satisfy neither atheists, faitheists, nor the faithful.  As Wood concluded:

What is needed is neither the overweening rationalist atheism of a Dawkins nor the rarefied religious belief of an Eagleton but a theologically engaged atheism that resembles disappointed belief.

Now Dr. Wood has kindly written a post on this website defending his position.  It was a comment following my analysis (and several people have replied there), but I thought I’d put it above the fold for discussion.  Here’s what he has to say:

As the author of the piece under discussion, might I comment on the commentary? Anyone remotely familiar with my writing (I am the author of a novel called “The Book Against God,” for goodness sake) will know that I am an atheist, and proud to call myself one (I grew up in a household both scientific and religious — a rather Victorian combination). [Please see my favorable review of Bart Ehrman’s “God’s Problem” in “The New Yorker.”] Having written often about my atheism, I wanted to do something a little different this time – – i.e. to please neither believers nor non-believers. Clearly, I’ve succeeded! As I made quite clear in the piece, I am on the side of Dawkins and Hitchens if I have to be, but I dislike their tone, their contempt for all religious belief, and their general tendency to treat all religious belief as if it were identical to Christian fundamentalism. Dawkins always sounds as if he wouldn’t mind too much if the European cathedrals were razed. For anyone, like myself, who loves literature and music, so saturated in religious belief and disbelief, one can’t simply dismiss this history it as if it were at the level of astrology or Gypsy Rose Lee.

The remarkable claim is made that I offer no evidence of this contempt for the history of belief; I would have thought that comparing the history of religious belief to John Cleese hitting his car in “Fawlty Towers” (Dawkins’s example of HADD, and the one I cite) is a very good example of that contempt — one can hear the High Table guffaw (”those absurd religionists!”). Dawkins is an essentially 19th-century figure; he sounds amazingly like Huxley, or the Russell of “Why I am not a Christian.” This was a text that made an enormous impact on me — when I was fifteen, or so. But one returns to it and finds it grating and oddly juvenile.

On the other hand, as I made clear, I have little time for the priests, the theologians, and the theorists. Nevertheless, it does seem to me more intellectually interesting to examine the nature of religious belief than simply to go on and on about what an enormous illusion it is. I KNOW it is an illusion, and so does everyone else on this website. So, let’s find something more interesting to say about this illusion, shall we? We are not always fighting the fundamentalists (who aren’t persuadable anyway, alas).
—James Wood

I’ve already had my say about Wood’s New Yorker piece, and would prefer to have the readers here have their say.  I will add just one statement as well as a response I got from someone else.  Religion is more than just an “enormous illusion.”  It is an enormous illusion that has the potential to do — and is doing — substantial harm to our world. Because of religion, women are being oppressed, people are getting stoned to death for adultery, HIV-infected people in Africa are being urged to abstain from condoms, people are killing each other over trivial differences in “sacred” works of fiction, and our own country was, in effect, a theocracy.  In America we’re still dealing with the remnants of medieval theology in questions about abortion, stem-cell research, and euthanasia.  Our world may well end in a paroxysm of religious conflict.  Many of the faithful don’t just hold their beliefs privately, but insist on inflicting them on others. This situation, and its attendant irrationality,  is what motivates the “new atheists,” and this motivation is precisely what Wood ignores. Instead, he cavils about subtle points of theology — and cathedrals.

I went to Harvard, and am not keen on Harvard-bashing.  Still, Wood’s “critique” smacks of an ivory-tower disconnect from the harsh realities of the world — and from real faith as it is lived and practiced.  Instead of dealing with these, he wants to score debating points, and to assert a smug moral superiority over both atheists and the faithful. Such is the New Yorker style.  After reading Wood’s response, a friend in the humanities, who is far more economical with prose than I, sent me this:

James Wood is a very smart literary critic.  In fact, believe it or not, there’s none smarter.  Still, there are some things he doesn’t understand.  Dawkins’s harsh view of religion isn’t warmed-over Victorianism or juvenile contempt for cathedrals.  It has to do with the effects, here and now, of literal religious belief on the conduct of nations and groups.

Wood inhabits a world of books, plus all of the cultural influences that go to make books interesting. Fine!  But meanwhile, our very existence is threatened by screwball religionists (including the Christians and Jews who want a war with Iran). To say that those of us who are alarmed about this fact don’t appreciate Chartres and Notre Dame is, to put it mildly, dilettantish.

McWhorter’s Mephitological Argument

September 2, 2009 • 6:23 am

Fie on Dawkins, Harris, Dennett, and Hitchens!  Their understanding of theology is on the level of a five-year-old; they completely fail to come to grips with all the effluent of sophisticated modern theology.  Take, for example, McWhorter’s Mephitological Argument for the Existence of God, which can be represented as follows:

mephitological theory

Fig. 1.  Graphic demonstration of MMA.  Of what use is half a stink?

This argument was first expounded here (start at the beginning and finish listening — unless you’re a masochist — at 3:00).  So far it has gone completely unrebutted by the “new atheists.”

h/t for graphics: Andrew Berry