Posts Tagged ‘evolution’

You damn dirty ape

30 March 2012

Only one of these is a real monkey (hint: it's the ape)

In the summer of 1861, a debate concerning a seahorse-shaped brain structure, and its existence in the simian brain, gripped Victorian England. Well that might be an exaggeration, but the “Great Hippocampus Question,” an anatomical feud waged primarily by Sir Richard Owen on one side and Thomas Henry Huxley on the other, did stir up enough public attention to inspire satirical poems, editorial cartoons, and an extended passage in Charles Kingsley’s exceedingly strange book, The Water-Babies, A Fairy Tale for a Land Baby,

He held very strange theories about a good many things. He had even got up once at the British Association, and declared that apes had hippopotamus majors in their brains just as men have. Which was a shocking thing to say; for, if it were so, what would become of the faith, hope, and charity of immortal millions?

Though really, after all, it don’t much matter; because—as Lord Dundreary and others would put it—nobody but men have hippopotamuses in their brains; so, if a hippopotamus was discovered in an ape’s brain, why it would not be one, you know, but something else.

Though Owen adhered to his own idiosyncratic evolutionary theories, he scoffed at Darwin’s suggestion that humans shared a common evolutionary history with primates. To prove the anatomical singularity of humans, the great anatomist conducted a detailed study of human and primate brains and asserted that the absence in apes of certain structures in apes, the posterior cornu and hippocampus minor, set humans clearly apart from primates.

Owen’s rival (and Darwin’s champion) Thomas Henry Huxley seized upon the fact that these structures are in fact demonstrably present in non-human primates, and proceeded to waggle monkey brains at academic peers and public audiences alike to illustrate Owen’s error. Writing to his wife Henrietta about one of his public lectures, Huxley raved “My working men stick by me wonderfully, the house being fuller than ever last night. By next Friday evening they will all be convinced that they are monkeys.”

All of this was called to mind by a debate that simmered across the interscape last week which sadly failed to capture the public imagination, but at least, you know, triggered a few tweets. I’m calling this the “Great Ape Clade/Grade Tirades of 2012.” It all began with a post by Jerry Coyne on his “notablog” Why Evolution is True,

I believe it was William Jennings Bryan who denied during the Scopes trial that man was a mammal. That one statement laid him low, exposing his Bible-ridden ignorance for what it is. Of course we are mammals, and of course Richard is an ape. The Wikipedia definition is as good as any:

Apes are Old World anthropoid mammals, more specifically a clade of tailless catarrhine primates, belonging to the biological superfamily Hominoidea.

Last time I looked, I was also a tailless catarrhine primate, so that makes me an ape as well.

This sparked a thought-provoking essay by anthropologist John Hawks “Humans aren’t monkeys. We aren’t apes, either.”

While I don’t entirely agree with Hawks–in fact I’m on record engaging in just the kind of misguided pedantry that Hawks deplores–he does make some good points. Hawks reminds us that there is no rule that vernacular names need to refer to monophyletic clades or formally recognized systematic groups. Evolutionary biologists that try to insist otherwise against popular usuage are swimming upstream at best, and at worst are probably reinforcing some negative stereotypes of scientists as out-of-touch type-A killjoys.

However Hawks’ advocacy for the paraphyletic “apes” and “monkeys” of everyday speech sparked a backlash. Brian Switek saw Hawks’ “humans aren’t apes” bet and raised him to “humans are fish.” Meanwhile Coyne doubled down on his original statement. Various tweets, retweets and countertweets ensued:

Setting aside for the moment the question of whose definition of “ape” is the correct one, it’s interesting to see the tension that arises when biological nomenclature and the popular vernacular converge and diverge. During this holy season of Lent we can all relate to the devout souls that happily fry up beaver tail and muskrat on Fridays, assured by the Vatican that beavers and muskrats are “fish” and not “meat.” And lest we think such distinctions are merely academic (or parochial), D. Graham Burnett’s Trying Leviathan describes how the question of whether or not whales are “fish” for tax purposes landed in a New York court in the 19th Century.

Of course, every fifth-grader learns that whales are not fish, but mammals. That is, until they get to my history of life class and they have to wrap their heads around the mind-boggling fact that whales are in fact “fish” in the most phylogenetically rigorous sense of the term, just as much as you or an elephant or a trout is.

Hawks finds such evolutionary rebranding of vernacular names distasteful,

We shouldn’t smuggle taxonomic principles into everyday language to make a political argument. That’s what “humans are apes” ultimately is — it’s an argument that we aren’t as great as we think we are.”

But elsewhere in his post Hawks belies that he in fact has his own taxonomically rigid view of what an “ape” and “monkey” properly are, it’s just that his taxonomy is not beholden to cladistic fashions.

My children can tell what an ape is. I work very hard to tell them why apes are different than monkeys. When they see a chimpanzee in a zoo, and other parents are telling their kids, “Look at the monkey!”, my children say, “That’s not a monkey, it’s an ape!”

If we must accept that humans are apes, then we must equally accept that chimpanzees are monkeys, and those awful parents at the zoo are right. I don’t.”

However, Hawks’ favored “correct” definitions for “ape” and “monkey” are actually rather modern constructions. Long before hominoids were known to the English-speaking world “Ape”  was a catchall word used for all primates, until “monkey” came into use around the 16th Century. The two were used rather interchangeably until “ape” began to be restricted to tail-less primates during the 18th Century. Even still, “ape” continued to encompass some tail-deficient primates such as the “Barbary ape,” a macaque that is “properly” now regarded as a monkey and not an ape. If the zoos themselves aren’t consistent I don’t know how we can expect the awful parents to get it right.

The fluid historical meanings of “monkey” and “ape” might be taken as evidence that vernacular taxonomies are inherently arbitrary. But in fact the etymological history reveals that as biological knowledge develops and increases, the vernacular language often changes to reflect. It was naturalists and biologists that emphasized the distinction between monkeys and apes and their taxonomy filtered into the public vocabulary, and eventually to Hawks and his children.

I don’t really think that nudging the English words “ape” and “monkey” into monophyletic compliance, with humans as apes and apes (including humans) as monkeys, is really a political tactic to demote humans. Rather I see it as a conversational tactic to promote evolutionary thinking. That seems to have been Huxley’s intent to convince the curious public that packed his lecture halls.
Alex Wild makes a great point in his post on the perennial “bug” vs. “bug” distinction, a taxonomic stumbling block that comes up within the first twenty minutes of any conversation with an entomologist (who understands “bug” to refer to a member of a specific order of insect possessing sucking mouthparts and hemelytrous wings rather than just, you know, any animal you might want to squash),

Bug” is a common name. What’s more, it is a common name for both the lay public and for insect specialists. That it refers to different organisms in the two cultural contexts does not change the fact that it is vernacular in both spheres.

Common names are particular to individual cultures and local contexts. That is their point. The beauty of common names is their fluidity. They are dynamic, ever-changing, adaptable. Vocabularies arise to suit people’s needs. Entomologists find a narrow meaning for Bug useful. Non-entomologists don’t. And that is fine.

The “traditional” senses of “ape” or “monkey” are not necessarily wrong, but neither should we try to restrict alternative uses. If Hawks still finds the old paraphyletic senses useful, far be it from me to try to exclude them.

Me, I’m on team Huxley.

Icon of evolution knocked from its perch, or, wait…how about “arthropod origins, waters around, muddied?”

10 August 2011

Since its original description six months ago, the fossil lobopod Diania has become one of the most celebrated fossils of all time, inspiring everything from elaborate back tattoos to a trendy sportswear line. This beloved “walking cactus” was championed by scientists as a key player in the origin of the most diverse and successful group of living animals. But startling new research suggests that this icon of evolution, this upstart URthropod, was in fact nothing more than an ordinary lobopod with bad skin.

In a series of brief communications published this week in Nature, two groups present revised analyses of the evolutionary relationships among 520 million year old fossil and its presumed relatives including euarthropods (e.g. insects, arachnids and crustaceans), anomalocarididsvelvet worms, water bears, and a variety of extinct stem-arthropods and lobopods, like the bizarre Hallucigenia. The phylogenetic analysis presented with the original description of Diania by Liu and colleagues found the creature to be closely related to a clade that included living arthropods and the outlaw Bavarian folk hero Schinderhannes, this result, coupled with the armored covered legs of Diania, was taken as an important clue to the origins of the stiff, jointed-appendages that are a hallmark of true arthropods.

However, the new reappraisals find Diania several nodes further removed from arthropod origins, mucking around in a polytomy that includes the tardigrades, onychophorans and extinct lobopodians. If these results are correct, it implies that the armored limbs of Diania are likely irrelevant to the origin of hardened jointed legs among arthropods. In a reply, Liu and company concede the tenuous placement of Diania in the family tree of arthropods and their relatives, but provide some additional support for their original interpretation and argue that further study is required to resolve the debate.

Surely, the question of whether Diania is a close relative of arthropods or not will continue to rock the paleontological community for years to come.

Refs:
Mounce, Ross CP and Matthew A Wills (2011) “Phylogenetic position of Diania challenged” Nature 476:E1 doi:10.1038/nature10266

Legg, David A et al. (2011) “Lobopodian phylogeny reanalysed” Nature 476:E1 doi:10.1038/nature10267

Liu, Jianni et al. (2011) “Reply” Nature 476:E1 doi:10.1038/nature10268

Ours is not to look back. Ours is to continue the crack.

14 May 2010

Our traditionalist is now beginning to worry, but he will grant this one last point pour mieux sauter.  OK, the very first Cambrian fauna included a plethora of alternative possibilities, all equally sensible and none leading to us.  But, surely, once the modern fauna arose in the next phase of the Cambrian, called Atdabanian after another Russian locality, then the boundaries and channels were finally set.  The arrival of trilobites, those familiar symbols of the Cambrian, must mark the end of craziness and the inception of predictability.  Let the good times roll.

This book is quite long enough already, and you do not want a “second verse, same as the first.” I merely point out that the Burgess Shale represents the early and maximal extent of the Atdabanian radiation.  The story of the Burgess Shale is the tale of life itself, not a unique and peculiar episode of possibilities gone wild.SJ Gould Wonderful Life (1989)

Had it in my head, tindered by a typically turgid comment I left over at Jerry Coyne’s blog, to write something about the phantasmic Fezouata fauna. About contingency and determinism and prehistoriography.

The first god had, in his garden, one of these I'm sure. Ordovician marrellomorph from the cover of this week's Nature / Van Roy et al. 2010. A strong contender for my next paleo-ink.

About Wonderful Life and Crucible of Creation. About broken molds and Technicolor films. About checking the guy’s rock record and replaying life’s wobbly mistracked tape.

this is what the late eighties was like

[I biked over the library after Schluter's talk and grabbed some books.  "That's a small book," the librarian remarked about the paperback version of WL, recut into hardback form, "but I'm sure it's filled with big ideas"]

And about GOBE and rocks from space. About evolutionary anachronism and steampunk anomalocaridids and Schinderhannes. About Chengjiang and Emu Bay and Orsten.

[I Googled.]

About Caratacus and the Ordovices and predictable outcomes. About the Cincinnati arch and Creation Museum atop it. About how those that ignore history are doomed to not worry about it too much, along the way.

[I read.]

And yes about the other big and massively under-celebrated early Paleozoic news this week: Cambrian Bryozoans (!) and Gondwanan echinoderms.

[I typed.]

And ultimately about how, really, all of this maybe shows not so much about the fickle nature of history or the inevitability of intelligence or even about foolish it is to draw deep philosophical lessons from a crappy fossil record.  But that, well, the Earth was a really weird place 550, 450, 250, 50, 5 million years ago and that we have a lot more surprises in store and a lot more to learn.  But we will, in fits and starts, and what we do discover will change our picture of our place in the universe.  Or maybe it won’t.

[I hit delete.]

Because it’s Friday afternoon, and that all sounds pretty damn pretentious and sappy and inconclusive.  Why not throw together a link-heavy meta-post [I thought], then sit back and watch the links decay over the years until all that’s left is an ambiguous smear that’s difficult to make any sense of.

Then I remembered that it’s post a Fall song on your blog day.

WWTD (what would Tufte do?)

16 March 2010

In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Light will be thrown on the origin of man and his history. - some dude.

We are a dreadfully narcissistic lot.  Perhaps nothing in the Origin has inspired more reflection or revulsion than Darwin’s passing reference to the promise that his ideas had to illuminate the origins of our own species.  Creationists might bloviate about bacterial flagella or blood-clotting proteins, but most are surprisingly willing to concede the fairly obvious genetic relations between, say, camels and llamas separated by two oceans and millions (or in the case of YECers maybe six thousand) years.  They even have a wonky pseudoscience, baraminology, that more or less admits that yes sister taxa have a common origin…up to a point.

But when it comes to one particular species, they invariably draw the line.  Of course as Darwin rightly anticipated, much has been learned in the last century and a half about the origins of our own species–it’s not my intention to review the history of these discoveries here, but I highly recommend Brian Switek’s comprehensive historical analysis as a great place to start.  But while much light has been thrown, perhaps an equal measure of ink has been shed in an attempt to visualize the evolutionary history of Homo sapiens.

Darwin’s own back of the envelope attempt seems, perhaps surprisingly, among the most straightforward of the lot, despite the bet-hedging and scratchouts:

It’s mostly been uphill from there, but often up the wrong the hill.  Like a teenager flexing in the mirror, then agonizing for an hour over a newly discovered blackhead.

I was reminded of all of this by this recent post by John Wilkins that reproduced this figure:

As they go, this diagram is not particularly bad, though as Wilkins notes the form does seem a bit dated.  However, I think that the discussion in the comments to that post reveal why this diagram is perhaps at least as confusing as it is revealing: are those truncated side-branches based on fossil data or just hypothetical?  Is the light brownish region supposed to be denoting some area of uncertainty and if so how?  Is there a 3rd dispersal out of Africa implied?  What exatly do those “?”s mean? (To be fair, I haven’t seen the figure caption which may address some or all of these questions.)

So, here then, gleaned from google are various other diagrams each ostensibly depicting more or less the same events: 5 million years of ape evolution in Africa plus some things that came after.  Feel free to leave your Tuftian critiques in the comments, bonus points for dropping fashionable jargon like “chart junk” “data-ink-ratio” &c.

A Trustworthy Pistosaur

8 March 2010

Just to prove that I am, in fact, working:

So it was possible to make a reconstruction of this skeleton with the skull of Pistosaurus.  It has the length of about 3 meters.  There is no doubt, that it represents a primitive Plesiosaur, the same result is also given by the details of the skull.  With exception of interclavicle and clavicle the whole skeleton is drawn from a single individual, the “Strunz skeleton”; the skull is drawn from Pistosaurus longaevus. It is possible that the “Strunz skeleton” is specifically different from the “Geissler skeleton” of which interclavicle and clavicle are taken, but both are Plesiosaurs, and so are both of the same described skulls.  An [sic] eventual difference will be small.  Therefore the reconstruction is a trustworthy Pistosaurus. — Von Huene 1948

Don’t know that I would trust him to give my kids a ride to school….

REF: Friedrich von Huene “Pistosaurus, a middle Triassic plesiosaur” American Journal of Science (January 1948), 246(1):46-52

Hypselorhachis sues National Geographic for Defamation of Character

5 March 2010

In a surprising move, the extinct archosaur Hypselorhachis filed an unprecedented post-mortem lawsuit against the National Geographic Society on Friday.  The enigmatic Triassic reptile was offended by being mistakenly labeled a “dinosaur” in an article that appeared on the National Geographic Website earlier this week (“Dinosaurs Ten Million Years Older Than Thought” March, 3, 2010 National Geographic News).

The focus of the article was the recent description of another non-dinosaur, Asilisaurus, a close dinosaur relative in the latest issue of the scientific journal Nature (Nesbitt et al. 2010 “Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira” Nature 464, 95-98doi:10.1038/nature08718).

In a statement released today Hypselorhachis asserts that the passing reference to “an early sail-backed dinosaur” in the caption of an illustration that accompanied the article was, “an underhanded attempt to smear my character and associate me with unsavory elements.”

“I just don’t understand.  They could have called me a ‘ctenosauriscid‘ a ‘poposaur‘ a ‘rauisuchian‘ a ‘pseudosuchian‘ a ‘crurotarsan‘  even an ‘archosaur’ without dragging my name through the gutter like this.  Hell, I would even have been fine with ‘hellasaur.’  But ‘dinosaur‘?  That’s just not right.  Someone has to put a stop to this sort of thing.”

Strange Bedfellows

The crusade has attracted some surprising allies.  Dimetrodon, a sail-backed synapsid from the Permian, has previously accused Hypselorhachis of being an “imposter,” a “total ripoff” and “less-original than Spinosaurus, really.”

Tensions between the two extinct animals flared last summer when Kanye  West interrupted Dimetrodon’s acceptance speech at the “Virgin Teen’s Choice Awards” for the category “Best Backbone.”  West grabbed the microphone saying, “Congratulations D’meet and I’mma let you finish, but Hypselorhachis had the best elongated neural arches of ALL TIME.”

In spite of the rivalry, Dimetrodon defends the merits of the lawsuit.  “As a frequent victim of false-dinosaur defamation, I wholeheartedly support Hypselorhachis on this one.  We non-dinosaurs have to stick together.”  Dimetrodon says that it will donate the proceeds from sales of its popular T-shirt to the Hypselorhachis legal defense fund.

Several pterosaurs and marine reptiles have also voiced their support for Hypselorhachis. National Geographic was not available for comment.

[um. yeah.  sorry.]

Permanent Ink

24 January 2010

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Which reminds me…

I meant to write about this when it was news.  Now it’s olds, which suits me fine.

Copy of Pearce's restoration of Belemnotheutis, re-drawn by Colin Stuart from Donovan and Crane (1992).

I.  The drawing above is of the extinct Jurassic cephalopod Belemnotheutis antiquus. In fact, it’s a fairly exact replica of a drawing made by Joseph Chaning Pearce who first named the genus in 1842 (shown at left).  Pearce may have intended to name the fossil Belemnoteuthis (teuthis=Gr. squid as in teuthology study of cephalopods), or he may have intentionally used a variant spelling.  Either way, Donovan and Crane 1992[pdf] argue that the original published spelling should stand according to the rules of taxonomic nomenclature.  Historically, Belemnoteuthis(sic) has been widely used and Richard Cowen has described Pearce’s original spelling as “barbarism.” Nevertheless there it stands: a possible typo enshrined into taxonomic priority.

II.  Engineering icon Isambard Kingdom Brunel, was the vision behind the construction of the Great Western Railway which linked London by rail to south west England (including the Jurassic Coast) and Wales during the 1830s and 40s.  Around 1840, rail workers constructing a line near the village of Christian Malford stumbled across incredibly well preserved fossils some of which were collected and studied by Pearce.  The site was eventually flooded and forgotten for more than a century and a half before it was rediscovered by British scientists just a few years ago.

III.  Which, the focus on all those new reports about that featured this drawing wasn’t mainly on the historical quirks surrounding the image or name at all but concerned instead the historical quirks surrounding the origin of the ink which is: FREAKING BELEMNITE INK!

Ink from a well-preserved Belemnotheutis, dead for 165 million years or so, was reconstituted and used to draw a copy of one of Pearce’s original drawings.

IV.  Which is really cool, but not nearly as unique as you might expect.

Joel Segal Books Blog does a nice job of putting fossil cephalopod ink into proper historical context, borrowing an image from my sidebar, a painting of Ichthyosaurus made by Henry De la Beche in 1834 using FREAKING BELEMNITE INK!

From Clary (2003)

Credit where it’s due: I nicked the picture from the doctoral dissertation of Renee M. Clary (2003) which explores the pioneering role De la Beche played in using imaginative visual aids to convey geological and paleobiological information.  Mandatory reading for anyone interested in the history of geology, the use of illustration in the earth sciences or the development “paleoart.”

Preserved ink sacs of fossil cephalopods - from William Buckland's Geology and Mineralogy with respect to Natural Theology (1836).

In fact, De la Beche was just one of a number of 19th century scholars and artists that messed around with reconstituted fossil ink.  In his “Bridgewater Treatise” Geology and Mineralogy with respect to Natural Theology (1836) William Buckland illustrated (so far as I know, with conventional ink),  the well-preserved ink sacs from several fossil cephalopods.  In that same work, Buckland gives an account of one of the earliest artistic experiments using fossil cephalopod ink:

Elizabeth Philpot, the often forgotten friend and associate of Mary Anning who is a central character in Tracy Cevalier’s recently published novel Remarkable Creatures, is also said to have painted with “fossil sepia” and sometimes credited with being the first to do so.  Other enterprising residents of Lyme are said to have followed suit painting  in an effort to cater to the burgeoning tourist industry fueled by Victorian fossil fever and the construction of the Great Western Railway.

I’m not sure whether any of the illustrations made by Chantrey, Philpot or their followers have survived, I haven’t been able to turn any up aside from De la Beche’s ichthyosaur.  Unlike the De la Beche drawing, other vintage fossil ink works might not be clearly labeled as such and could easily be sitting in a private collection or a museum forgotten and unrecognized.  Philpot’s or Chantrey’s original works, most likely long gone, would be priceless historical gems of the finest order.

V. Fossil ink makes literary cameos in the work of Jules Verne and the poet Martin Farquhar Tupper.  It also turns up in one of my favorite essays of all time, Thomas Henry Huxley’s “On the Method of Zadig”:

“No amount of physiological reasoning could enable any one to say whether the animal which fabricated the Belemnite was more like Nautilus, or more like Spirula. But the accidental discovery of Belemnites in due connection with black elongated masses which were: certainly fossilised ink-bags, inasmuch as the ink could be ground up and used for painting as well as if it were recent sepia, settled the question; and it became perfectly safe to prophesy that the creature which fabricated the Belemnite was a two-gilled cephalopod with suckers on its arms, and with all the other essential features of our living squids, cuttle-fishes, and Spirulæ. The palæontologist was, by this time, able to speak as confidently about the animal of the Belemnite, as Zadig was respecting the queen’s spaniel. He could give a very fair description of its external appearance, and even enter pretty fully into the details of its internal organisation, and yet could declare that neither he, nor any one else, had ever seen one.”  Thomas Henry Huxley “On the Method of Zadig” (1880)

VI.  Pigments, paints, dyes and inks come either from dead organisms or minerals, and so all have some biological or geological story to tell.  The case at hand straddles both categories, which seems unique until you remember the ubiquity of “synthetic” inks distilled from petroleum that is the remnants of marine organisms, dead and buried for millions of years.  That might include some of the ink used to run the Belemnotheutis newspaper stories, unless British newspaper printers have all switched to soy-based inks like their U.S. counterparts.  Your keyboard and mouse are probably made from sea animals.  If you print this post out (which I can’t imagine why but just go with me here) the ink you use, and perhaps the energy to do it, are quite possibly the byproducts of long dead phytoplankton.

VII.  And as long as we’re talking autochthonous/authigenic art, I have to mention Matt Celeskey’s work with 200+ million year old Triassic charcoal.  Matt, in turn, turned me on to Alexis Rockman whose “field drawings” use site-specific pigments themed around of both living and fossil ecosystems ranging from the Burgess Shale and La Brea Tar Pits to Fresh Kills landfill.

VIII.  Here then for almost no reason except that I like the picture is Brunel, posed beside the launching chains of the SS Great Eastern, whom Brunel affectionately called the “Great Babe.”  The ship will experience a steam explosion, killing 5, before being repaired, sent across the Atlantic as a passenger vessel half-a-dozen times nearly sinking once before being converted to cable laying ship and laying the first Trans-Atlantic telegraph cable, later converted into a floating music hall and promotional gimmick and eventually broken up and sold for scrap.  Which has nothing to do with anything.  Like I said, I just like the picture.

And if you made it this far without being tempted by at least one of those hyperlinks, I can’t help you.

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