Three years of the Sun in three minutes

May 12, 2013 • 4:25 am

Even a blind pig can find an acorn, and even HuffPo occasionally has something worth seeing, like this video:

NASA has released a three-year time-lapse video of our star, compiled from incredible images captured by the Solar Dynamics Observatory (SDO) spacecraft.

The time-lapse compresses about two images a day into a few minutes. And don’t miss these highlights in the video above (time-marked by NASA): a partial eclipse by the moon at 0:30, a flare at 1:11, and the brief appearance of comet Lovejoy at 1:28. [JAC note: these incursions are quick, so watch carefully!]

NASA’s SDO has filmed the sun since spring 2010, providing breathtaking images. So think of this latest video as a “best of” reel, complete with stirring background music.

The music? According to the YouTube site, it’s “”A Lady’s Errand of Love,’ composed and performed by Martin Lass” (his website is here).

Rabbi Wolpe impugns Dawkins’s status as “world’s leading intellectual”

May 11, 2013 • 11:15 am

Liberal Rabbi David Wolpe, who with fellow rabbi Bradley Artson was roundly trounced in a debate with Sam Harris and Christopher Hitchens over the existence of an afterlife, is butthurt at Prospect Magazine‘s naming of Richard Dawkins as the “world’ leading intellectual.”  To redress his grievance, Wolpe has a piece in this week’s PuffHo questioning Prospect’s decision: “Is Richard Dawkins really the world’s leading intellectual?”  As Wolpe notes, “If Dawkins is indeed our best, the life of the mind is in a precarious state.”

What’s Wolpe’s beef? Here’s why, he says, Dawkins doesn’t qualify:

  • Historical ignorance. Wolpe argues that, contra Dawkins, Hitler really was more evil than Caligula, and then faults Dawkins for a few other statements:

“Of course, this historical misfire comes from the same book, ‘The God Delusion,”‘that insists, “I do not believe there is an atheist in the world who would bulldoze Mecca — or Chartres, York Minster or Notre Dame.” As Alistair McGrath points out, that would surprise anyone who is aware of the fact that the explicitly atheistic Soviet regime destroyed the vast majority of churches (and priests) between 1918-1941. The Tamil Tigers (again, atheistic, and the inventors of suicide vests) leveled countless Buddhist sites of worship.

Well, maybe there are one or two atheists who would bulldoze Chartres right now, but Dawkins is right in the main. I doubt that a single one of my readers would want to see those cathedrals destroyed. For crying out loud, it’s this kind of nitpicking that Wolpe uses to denigrate Dawkins’s historical sense? What about all the things about history Dawkins got unequivocally right, like the evils committed in the name of faith?

  • Intellectual narrowness.  Again, Wolpe picks a couple of quotes out of Dawkins’s oeuvre to discredit him completely.  As he writes, “Dawkins exhibits none of an intellectual’s characteristic ability to understand the second side of the argument. He not only discounts religious argument, he is unable to believe in the integrity and sincerity of those scientists who disagree with him. Referring to a fundamentalist who gave up science because he could not reconcile the two [Kurt Wise], Dawkins suggests that he be given the Templeton prize (a prize for scientists who make spiritual contributions) because He might be the first really sincere recipient.’. . . The inability to credit your opponent’s arguments or intentions is not a mark intellectual distinction.”

Actually, I think it’s pretty clear that Dawkins thinks that many religious people are sincere, especially those who commit evil in the name of their faith. As for not “understanding the second side of the argument,” I’m not sure what the good rabbi means. I can understand why religious people make some of the arguments they do (brainwashing, wish-thinking, and so on), and parse those arguments so that I understand them (“yes, I understand you think the world was created 10,000 years ago”), but taking most religious arguments as seriously as one takes a credible idea, like that of sexual selection? I don’t think so.  In fact, in The God Delusion Dawkins does take on board many arguments for God and uses intellectual tools to dismantle them (e.g., the Cosmological and Ontological arguments and so on).  The influence of that book rests, in fact, precisely on taking the arguments for religion seriously and then dismantling them.

  • Moral obtuseness.  Ah, yes: the old “child abuse” statement that has furnished fodder for many of the faithful:

“To write, as Dawkins has, not only that religion is a form of child abuse but indeed may be more damaging than actual sexual abuse, is closer to raving than to reason: ‘Priestly groping of child bodies is disgusting. But it may be less harmful in the long run than priestly subversion of child minds.’ Puerile swipes at the religion of a billion people are beneath any intellectual, much less a ‘leading’ one.”

Wolpe then points out the many good things that religious people do. But it’s hardly a “puerile swipe” to consider many forms of religious indoctrination as child abuse. I know several Catholics who, even past the age of 30, have been scarred for life by the guilt instilled in them by nuns and priests, and we all know how madrasas deform young and impressionable minds.

Nothing angers religious people more than the accusation that religious indoctrination can be seen as child abuse. And yet that accusation is often completely accurate.  People like Wolpe don’t like to think of themselves, or their coreligionists, as abusive, but of course some of Wolpe’s fellow Jews regularly snip off the tips of children’s penises—with their teeth!—and turn their daughters into second-class citizens, forced to take ritual baths of “purification” after menstruating.

Yes, surely some religious people do good, and sometimes in the name of religion, but many of those people would have done good even if no religion existed, not to mention the fact that many religious “charities” are vehicles to proselytize.

Wolpe notes this: “Central to the evaluation of an intellectual’s integrity is whether they are arguing with the best in the opposing position.”  But what, exactly, does he mean by the “best” in the religious position? The best deeds of religious people? The most “sophisticated” theological thought? Given the absence of evidence for God, there is no “best” religious argument; there are only better or worse behaviors.  And behaviors in modern societies that are largely free of religion, like those of Scandinavia, aren’t palpably worse (and probably better) than those of religious societies like the U.S. In terms of the group morality inspired by religion, I’d say that for most faiths it’s worse than secular humanism.

Wolpe then contrasts Dawkins’s “obstuse” atheism with that of Michael Shermer:

“Thoughtful atheism is an important contribution to the debate. Far more credible is the conclusion of an ideological confederate of Dawkins, editor of Skeptic magazine, Michael Shermer: ‘However for every one of these grand tragedies there are a thousand acts of personal kindness that go unreported. … Religion, like all social institutions of such historical depth and cultural impact, cannot be reduced to an unambiguous good or evil.'”

Indeed, for even Hitler built the Autobahn! The question isn’t whether there may be some people inspired to do good by faith, but whether the tenets of that faith, without which it would inspire no behaviors, are true.  And it is here that Dawkins has made his mark, for by his writings, eloquence, and dogged, science-inspired questioning, he has rammed home a central tenet of New Atheism: religion depends on empirical statements about the universe, and without those statements religion crumbles. God is a hypothesis, and a bad one.

In fact, the Prospect Magazine criteria have been widely misinterpreted. The magazine wasn’t trying to find the world’s leading intellectual of the decade, or of our time, but those intellectuals who had the biggest influence over the past year. As Prospect notes:

The panelists who drew up the longlist of 65 gave credit for the currency of candidates’ work—their influence over the past 12 months and their continuing significance for this year’s biggest questions.

By those lights, Dawkins surely qualifies.  He has, along with the other prominent New Atheists, made nonbelief respectable again, and an intellectually solid position.  He has inspired thousands of secret nonbelievers to make their voices heard, thereby hastening the end of the world’s last great superstition.  That certainly makes him one of the world’s most influential intellectuals.

And I’ll tell you who is not one of the world’s great intellectuals: the credulous faithhead Rabbi David Wolpe, mewling and puking before a nonexistent Yahweh.

h/t: SGM

Readers’ wildlife photos: the malachite sunbird (a creationist icon)

May 11, 2013 • 8:33 am

Reader Richard, who lives near Cape Town, South Africa, sent some photos he took of a malachite sunbird, and noted this:

A Nectarinia famosa visits our garden each year when these flowers emerge.

Sunbirds, including this species, are the Old World equivalent of hummingbirds: an example of convergent evolution. They make their living, like hummingbirds, by hovering before flowers and sipping the nectar. While working on São Tomé, I sometimes encountered one of the two endemic species there, the Giant Sunbird (much prized on birders’ life lists; the other species is the Principe Sunbird).

Malachite Nov 2009 015

Malachite Nov 2009 002

Looking for videos showing this bird, I found a creationist one showing that the species helps prove God!  One plant (the “rat’s tail”) apparently has evolved perches for the sunbird, enabling the animal to access its nectar!

As the video’s narrator notes (while chuckling about the stupidity of evolutionists):

“If evolution was true, how could such a plant survive until it could learn enough about its pollinator—and about genetics—to evolve a special growth just for its pollinator. Heh! This sounds like a silly question, but if evolution is true, that question must be answered, and answered scientifically.”

The narrator says this is a “silly question,” and is best answered by invoking God’s creation of the sunbird for the plant, and the plant for the sunbird. But in so doing, he describes the crucial experiment that actually shows the evolutionary advantage for a plant to evolve a perch.  This is one of the most bizarre creationist arguments I’ve ever seen, since the evolutionary pressure to evolve a perch is so obvious that there’s no need to even think of divine creation. Any listener who knew even a bit about natural selection would see that the evolved perch is no mystery.

You can find several videos of the malachite sunbird in the wild at this site.

Cheerleaders win right to display Jesus banners at public school sporting events

May 11, 2013 • 5:23 am

Last October I reported that cheerleaders in Kountze, Texas, were displaying Christian banners, with slogans from the New Testament, at high-school football games. The Freedom from Religion Foundation (FFRF) brought suit against the school district, maintaining, correctly, that such displays violated the First Amendment, which prohibits government endorsement of religion.  The case was then working its way through the courts after the displays were first rejected and then reinstated by a higher court.

ABC News reports this week that a state district court has ruled, however, that the banners are legal:

State District Judge Steven Thomas determined the Kountze High School cheerleaders’ banners are constitutionally permissible. In the ruling, Thomas determined that no law “prohibits cheerleaders from using religious-themed banners at school sporting events.”

The Kountze school district had initially said the banners could not be displayed after receiving a complaint about them in September from the Freedom From Religion Foundation. The foundation argued the banners violated the so-called First Amendment Establishment Clause that bars government — or publicly funded school districts in this case — from establishing or endorsing a religion.

Thomas ruled that the establishment clause does not prohibit the use of such religious-themed banners at school sporting events.

“This is a great victory for the cheerleaders and now they’re going to be able to have their banners,” said Hiram Sasser, a lead attorney for the Liberty Institute, a Plano, Texas-based nonprofit law firm that represented the cheerleaders.

. . . The cheerleaders in Kountze, located about 95 miles northeast of Houston, were supported by various state officials, including Gov. Rick Perry and Texas Attorney General Greg Abbott, who filed court papers seeking to intervene on their behalf. A Facebook group created after the ban, Support Kountze Kids Faith, has more than 45,000 members.

Abbott praised the court’s ruling on Wednesday, calling it a “victory for religious liberties.”

Perry in a statement said the cheerleaders “showed great resolve and maturity beyond their years in standing up for their beliefs and constitutional rights.”

Constitutional rights? What reading of the Constitution allows such rights?

It is, of course, settled law that schools cannot have official prayers broadcast before sporting events.  The cheerleaders are representatives of the school, wearing school uniforms. I don’t get the difference.

The Freedom From Religion Foundation’s co-president, Annie Laurie Gaylor, was disappointed with the ruling, saying the banners “carry the appearance of school endorsement and favoritism, turning Christians into insiders and non-Christians and nonbelievers into outsiders.”

The Anti-Defamation League also criticized the ruling, calling it “misguided” and saying it “flies in the face of clear U.S. Supreme Court and other rulings.”

Curiously, attorneys for the school district advised the schools that these displays violated constitutional law:

Attorneys for the Kountze school district, in initially advising the superintendent to ban the religious statements on the cheerleaders’ banners, argued there have been several precedent-setting rulings by the Supreme Court.

In one of the more well-known cases, the court ruled in 2000 that a practice of allowing student-led prayer ahead of high school football games in Texas’ Santa Fe Independent School District violated the Constitution. In 1992, the Supreme Court made a similar ruling in a Rhode Island case that argued a rabbi’s prayer at a middle school graduation ceremony also violated the Constitution.

But public sentiment, combined with the pro-religion stance of state officials, was too strong.  And the judge is wrong. Let’s hope that the FFRF appeals.

The forces of religion are ever busy feeding in America, and don’t care about the Constitution. What would happen if the cheerleaders displayed banners with verses from the Qur’an?

Really, who can argue that this is legal?:

Cheerleaders 2

Kountze-Sign-Ban-jpg

Caturday felid trifecta: Popcorn kittens, boxophilic cats, and a girl and her moggie

May 11, 2013 • 4:44 am

We have not one, not two, but three features for a dreary Caturday (at least in Chicago). First up, the famous Popcorn Kittens:

From Erica Camp:

These are just some kittens I rescued who went crazy after they felt a plastic tarp on their feet for the first time. I was just trying to make them a bigger place to be able to run around, but instead it ended up being a playpen! That is why I chose the music of Scott Joplin, because it reminded me of one of those old movies they play ragtime music to, while funny things are happening. It was too hilarious not to record, so I tried to capture the funniest moments in this video compilation. =) Enjoy!

From the Guardian, fifty bazillion pictures of cats in cardboard boxes, including these (TRIGGER WARNING: there are some d-gs, too):
136819532421703aeaf776fd18850a1ca74dac499c53c
Why do cats do this? My theory, which is mine, is that it expresses an ancestral desire to “den”—to rest in an enclosed space to protect you from predators and the elements.
Boxcat 1
Economist by profession and photographer by calling, Andy Prokh takes charming black-and-white photos of his 4-year-old daughter and their cat. He’s been capturing the beautiful friendship ever since his offspring Katherine was born. At that time the pet was already two years old, so Katherine has spent her entire life with LiLu Blue Royal Lada. The British Shorthair seems to enjoy playing with the girl as much as she does.
There are nineteen cute and fanciful photos; here are but four:
girl-and-cat-andy-prokh-1
girl-and-cat-andy-prokh-7
girl-and-cat-andy-prokh-16
girl-and-cat-andy-prokh-12

h/t: Matthew Cobb, Richard, Su

Cat versus stoat

May 10, 2013 • 1:39 pm

Clearly, the advantage here is to the stoat. Look how fast that damn thing is!

A stoat is another name for the short-tailed weasel (Mustela erminea), which, when it turns white in winter, is known as the ermine.

This play behavior prepares the young stoat for its life as a vicious predator. To see that in action, Attenborough has a video of a stoat chasing and killing a rabbit, though it may offend the gentle-hearted.

Note that the stoat’s jumping on the cat’s back and neck is exactly what it does in nature when making a kill.

h/t: SGM

God help me

May 10, 2013 • 11:33 am

This is a good example of passive-aggressive Christianity, or should I say faux-friendly Christianity:

Haught

Not so friendly inside!  It’s hilarious, and the fun starts on the second page of the text:

p. 10 Many educated people have no doubt that faith is irreconcilable with science. For instance, Jerry Coyne, an evolutionist at the University of Chicago believes that Charles Darwin’s theory of evolution has demolished the idea of God once and for all. Contemporary best-selling authors Richard Dawkins, Sam Harris, Christopher Hitchens, and Daniel Dennett, known as the “New Atheists,” agree. If you are a scientist, they declare, you cannot honestly believe in God. . . Faith is a mere fiction and theology a waste of time.¹

Footnote 1, gives, as a reference for my views, Why Evolution is True. Unfortunately, the ideas attributed to me don’t appear in that book, which mentions religion only tangentially, and not as Haught says.

p. 41: Richard Dawkins, Daniel Dennett, Jerry Coyne, E. O. Wilson, Stephen Jay Gould, and many other evolutionists spoil the credibility of Darwin’s good science when they unwisely alloy evolutionary biology with a materialistic worldview. They thus distort the true nature of science by wrapping Darwin’s discoveries snugly in the belief system we are calling “evolutionary naturalism.” They contaminate Darwin’s science by imposing on it an extraneous ideology. In doing so they unnecessarily make Darwin’s neutral scientific findings theologically unacceptable on any terms.

What?  Darwin arrived at his theory via a materialistic worldview and, throughout The Origin, repeatedly shows that the facts of biology and geology refute creationist claims. Darwin’s findings are hardly neutral with respect to materialism, which, by the way, is not an ideology but a practice derived from the experience of seeing that it works. It’s like calling plumbing an “ideology.

pp 101-102: Jerry Coyne of the University of Chicago, whose faith in evolutionary naturalism has no limits, will continue to remind us that the high degree of accident and blind necessity in biological evolution renders the emergence of mind nothing but a fluke of nature. (Why he puts so much trust in his own mind, therefore, remains a mystery.)

Facepalm again.  Natural selection, my dear Dr. Haught, is not either “accident or blind necessity”: it is the concatenation of mutations (which might be conceived of as accidents) and the nonrandom disposition of those mutations based on their contribution to reproduction.

Further, I’m not sure what he means by “blind necessity.”  As for mind being nothing but a fluke of nature, well, that’s probably true, at least the human mind, since I don’t see our evolution as inevitable (it may have depended on mutations that are based on quantum effects). As for trusting my own mind, well, I’ve been able to do that pretty well doing that in the past sixty-odd years.  So experience tells me that my mind’s apprehensions are pretty trustworthy. I’m still healthy, have good friends, good food, and other things, many of which are the products of science—i.e., trusting other peoples’ minds. And my mind has also been valuable in helping me detect terrible arguments based on wish-thinking alone, such as those appearing between the covers of your book.  I trust my own mind because, by and large, it’s proven trustworthy.  Contrast that with the pronouncements of your own Catholic faith, which are not only unsubstantiated, but have led to terrible evils in the world. (When, by the way, are you, Dr. Haught, going to decry the child rape endemic in your church? And what happened to limbo, Hell, Noah’s Flood, and Adam and Eve? How trustworthy were the minds of the Church fathers?)

Haught appears to have been taken in by the specious arguments of Alvin Plantinga, who claims that evolution alone could never have given us minds that perceive the truth. To these dudes, such accurate perception requires the sensus divinitatus given us by the Christian God (Lord knows how the Aztecs were able to function!).

p. 157: Cosmic pessimists clearly show that they too trust the capacity of their own minds to reach these exquisite goals [finding intelligibility and truth].  All you have to do is read books by the likes of Richard Dawkins, Daniel Denneett, and Jerry Coyne to sense the enormous degree of confidence they have in their own cognitional performance. And yet, if the universe that gave birth to their minds is essentially mindless (and hence pointless), as they claim, then they have no good reason to trust these same minds.

Well, how about if those minds have repeatedly led us to results that seem correct?  After all, if a dog gets petted by his owner every time they meet, the dog comes to like the owner and expect the petting.  Doesn’t he have a good reason to trust his owner? Did God also give dogs a “sensus canis“?

What a muddle this argument is!  First of all, our minds aren’t absolutely reliable: we are victims of all sorts of optical, emotional, and cognitive illusions. (And metaphysical ones, I might add, such as Catholicism.) Second, natural selection is a good way of evolving = the ability to find out true things about the universe that impinge on our reproduction and survival. Third, science is just a refinement of the normal way we find truth in our own lives, like why the toilet isn’t flushing or the car won’t start. And we have other people’s minds that can cross-check each other and help us learn, and learning itself is of course a product of natural selection.  Those who didn’t learn how to deal with new circumstances didn’t survive. Rationality is itself an adaptation, and that, combined with learning, gives us a pretty good toolkit to find out about the universe. In contrast, religion has given us no useful way to find out what’s true about the universe, and has in fact repeatedly misled us. That’s why science has, over and over again, corrected the “truths” produced by religious minds.

Arguing that our ability to rely on our imperfect faculties to find truth is a proof of God seems to me a piece of extraordinary delusion and stupidity.

But Haught is right about one thing: I do think that theology is a waste of time.  It involves people with brains, such as Haught, sitting around and rationalizing or explicating about “truths” for which there is not the slightest bit of evidence. It’s a discipline without a subject, and a vast diversion of human thought from more productive activities. What Haught could have accomplished had he been, say, a doctor or a scientist instead of an apologist who gets paid enormous sums of money to gull the public into thinking that there’s a Vast Loving Depth behind the universe!

Why on earth do narwhals have tusks?

May 10, 2013 • 8:46 am

Courtesy of alert reader QOS., I learned about an old bit of research from 2005, reported in the Harvard Gazette, purporting to answer the question above—but probably not succeeding. But let’s leave that aside for the nonce and learn a bit about narwhals. For reasons that elude me, they seem to have become the iconic species of atheists, perhaps because they’re a living unicorn.

The narwhal (Monodon monoceros) is a small toothed whale (odontocete) that lives in the Arctic portions of the Atlantic ocean. It’s an odontocete but has lost all its teeth but one—the tusk. The tusk is a very long canine tooth, and is found only in males.  It’s a spiral tooth and is placed not only asymmetrically (off to one side), but directionally asymmetrically—that is, it’s almost invariably on the left side. There’s a ton of good narwhal information at the “Narwhal FAQ” site of Kristin Laidre, a research scientist at the University of Washington. Here’s a few things you might not have known about the creature:

  • The tusk is actually a tooth that protrudes through the gum, and one of the few spiral teeth in nature. It’s also directionally asymmetrical; that is, it is off-center and nearly always on the left side of the body. Such directional asymmetries are not that common in animals (we, of course have them: in the placement of our internal organs, for instance), but to me they pose an evolutionary conundrum. How did a directional asymmetry evolve in the first place? Given an anterior-posterior and a top-bottom developmental gradient, left and right should then be embryologically symmetrical, so how does a gene “know” if it’s on the left or right from developmental cues? Once there’s an initial directional asymmetry, of course, then further asymmetries can cue on that one, but it’s a mystery to me how the first directional asymmetry (i.e., left vs. right) got off the ground in evolution.
  • Nota bene: by and large, only males have tusks, and (as the photo below shows) are often seen “jousting” with them while females linger nearby.  Only rarely does one see a tusked female, and two-tusked males are known as well.
  • Narwhals can live to be up to 90 years old.  This has been determined using “amino acid racemization” of aspartic acid.  That is, all of the amino acids we incorporate into our body are the L-form, but in tooth enamel of mammals, L-forms convert to D-forms (“racemization”) at a constant rate with age. Thus the relative proportion of D- versis L-aspartic acid gives you an idea of how old a mammal is.
  • “The narwhal is one of the deepest diving whales, with a record dive depth of approximately 1800 m (5905 ft., over one mile). . . Narwhals typically dive to at least 800 metres between 18 and 25 times per day every day for 6 months; over half reach at least 1,500 meters (4,500 feet). In addition to making their remarkably deep dives, narwhals also spend a large amount of their time below 800 meters (> 3 hours per day). This is an incredible amount of time at a depth where pressure can exceed 2200 PSI (1500 atmospheres) and life exists in complete darkness.”
  • Finally, narwhals eat well, when they do eat (they largely fast during summer). Their diet, which explains why they’re always diving so deep, consists of fine Greenland halibut and squid, with a soupçon of other seafood like skate eggs.

A while back I did a long post on narwhal biology, concentrating on their tusks and teeth. (The tusk is the only tooth that erupts, but they have vestigial teeth, remnants of their ancestry, embedded in the jawbone. Fetuses also begin to develop teeth but abort them.  I included a video of narwhal behavior.)

Here’s a picture of male narwhals “tusking,” from the Narwhal News Network, which has a bazillion other narwhal photos:

narwhals-tusking

An article by Leah Gourley in the Harvard Gazette: “Marine biology mystery solved“, suggested that the question “Why tusks” had been answered, with the solution given at a meeting by Martin Nweeia at the Harvard School of Dental Medicine. The supposed answer involved chemosensory and proprioceptive properties of the tusk:

Nweeia has discovered that the narwhal’s tooth has hydrodynamic sensor capabilities. Ten million tiny nerve connections tunnel their way from the central nerve of the narwhal tusk to its outer surface. Though seemingly rigid and hard, the tusk is like a membrane with an extremely sensitive surface, capable of detecting changes in water temperature, pressure, and particle gradients. Because these whales can detect particle gradients in water, they are capable of discerning the salinity of the water, which could help them survive in their Arctic ice environment. It also allows the whales to detect water particles characteristic of the fish that constitute their diet. There is no comparison in nature in tooth form, expression, and functional adaptation.

“Why would a tusk break the rules of normal development by expressing millions of sensory pathways that connect its nervous system to the frigid arctic environment?” asks Nweeia. “Such a finding is startling and indeed surprised all of us who discovered it.” Nweeia collaborated on this project with Frederick Eichmiller, director of the Paffenbarger Research Center at the National Institute of Standards and Technology, and James Mead, curator of Marine Mammals at the National Museum of Natural History of the Smithsonian Institution.

Well, that sounds well and good, but there’s one problem.  If the tusk evolved for this reason, why is it missing in females? Presumably females would have the same need to detect particle gradients and salinity.

That suggests two things. First, that the initial evolution of the structure was driven not by general adaptation to the environment, but by sexual selection. Males could either fight with the things, with the bigger or more deftly wielded tuskers winning, or simply “feel each other out” by mutual tusking; in both cases the winner gets reproductive success by winning nearby females.

Then why the chemosensory and proprioceptive capacities?  Well, there are two possibilities. First, these could have evolved for the reasons suggested after the tusk had already arisen by sexual selection. Then would then be a general adaptation made possible by the prior appearance of an “outside sensor platform”—in other words the capacities discovered by Nweeia et al. could be what Steve Gould called a exaptations.  Or, their chemosensory functions might have evolved simply to detect other males’ scents when jousting; after all, the males don’t really battle it out when jousting, but seem to gently rub tusks while making noises.

In either case, it appears that the adaptive value of chemosensory teeth hasn’t been sufficient to allow their appearance in females; which, after all, carry the same genes that are present in males—including the genes for tusks. Those genes simply aren’t activated in females, ergo no tusks.  There must be a disadvantage for females to have tusks that outweighs their chemosensory advantage. Whatever the “advantage” for females (who don’t have the extra benefit of jousting for mates), it could be outweighed by having to carry a cumbersome apparatus that could get injured.

I’m surprised, actually, that neither the author of the paper nor of the article mention this obvious problem. Gourley does allude to sexual selection as previous ideas for the evolution of tusks, but gets even that wrong:

In the past, many theories have been presented to explain the tooth’s purpose and function, none of which have been accepted as definitive. One of the most common is that the tooth is used to display aggression between males, who joust with each other for social hierarchy. Another is that the tooth is a secondary sexual characteristic, like a peacock’s feathers or a lion’s mane.

But these are not distinct “theories”!  If a character evolved by sexual selection, it is a secondary sexual characteristic. They are not competing explanations. A lion’s mane, after all, probably serves as a kind of plumage that attracts females, showing something about the male’s age or condition.

Finally, in arguing that the mystery of the tusk has been “solved,” Gourley conflates two different explanations—explanations that impelled Gould to distinguish between “adaptations” and “exaptations”. Gourley says that the “solved” mystery is this:

“. . . why does the narwhal, or “unicorn,” whale have an 8-foot-long tooth emerging from its head, and what is its function?

There are two separate questions here.  First, what were the selective pressures that caused the structure to appear in the first place (note to Larry Moran: I seriously doubt that genetic drift is responsible for this trait!)? In my view, it’s clearly sexual selection, though exactly how it worked is a mystery (are males with bigger tusks simply older, in better condition, or do they have better genes?).  Second, how do the tusks function now?  For a feature can acquire new functions after it arose for other reasons, just as the penguin’s “wings” now enable it to swim.  The flippers originally arose by natural selection for flight, and after penguin ancestors lost that function (or during its loss), the vestigial wings became useful for swimming. In the case of the narwhal, the tusk could have both the original evolutionary function and also a new one.  The point is that current function may bear little relationship to the selective pressures that led a trait to evolve in the first place.

I notice that in the intervening eight years since this report was made, Nweeia and his colleagues have published a nice article on the vestigial teeth of narwhals, but have apparently published nothing about this remarkable discovery of the chemosensory and tactile functions of the tusk. And even in an interview about that article, Nweeia goes wrong about evolution:

“The whole thing that is great about the teeth of the narwhal is that nothing makes sense,” Nweeia adds. “The tusks are an extreme example of dental asymmetry. They exhibit uncharacteristic dimorphic or sexual expressions since females do not exhibit erupted tusks as commonly as males. Also, the tusk has a straight axis and a spiraled morphology.  Conventional mechanisms of evolution do not help explain these expressions of teeth.”

Well, the asymmetry can make sense. If only one tusk was useful in jousting, and if it’s simply an enlarged canine tooth, well, evolution has to choose either a left or right canine. As for the sexual dimorphism, explanations for that are well known. We may not know exactly how the tusk is used, or how it evolved, but the path for understanding is wide open.