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I awoke on the floor in the aisle of my United Airlines flight to Los Angeles, with three unfamiliar men crouched around me, bearing serious expressions as they looked down on my prone body.

I was next to my seat. My daughter was crying inconsolably in her seat next to mine, and my wife was calling to me with an urgent tone from the next seat over.

Gradually, as my confusion faded and the men let go of me (I’d been cursing them out, in mangled words because I had bitten my tongue), I became aware that I was in intense pain, I could not move much, and my wife’s words became clearer:

I’d had a seizure. And so our relaxing family holiday, which had only just begun, ended. And so my waking nightmare began.

Stomach-Churning Rating: 5/10; lots of Anatomy Fail CT/x-ray images and gruesome descriptions, and a photo of some bruising.

I was helped back into my seat as I regained my senses, I noticed blood on me from my tongue, and I learned that we were 2 hours away from L.A. As I was acting more normal, and we were 5/6 of our journey along, there was no need to prematurely land the flight. I had fallen asleep while watching “22 Jump Street”, about 1.5 hrs in, and that’s when my seizure struck– much like the previous two seizures I’d had. Jonah Hill could be ruled out as a culprit, but going to sleep was an enabling factor. I got some over-the-counter painkillers and sat in a daze as time ticked by, we landed, and paramedics boarded the plane to whisk me off to the hospital with my family.

Two gruelling days and nights in a California hospital later, with my first night spent in a haze of clinical tests, begging for painkillers, yelling in pain every time I moved, and otherwise keeping my hospital roommate awake, the story became clearer: my seizure was so intense that I’d dislocated my right shoulder (unfortunately I’d not had much pain relief when the emergency room staff popped it back into my glenoid), probably dislocated my left shoulder too but then relocated it myself admist my thrashing, and done this (cue Anatomy Fail images):

Left shoulder, with the offending greater tubercle/tuberosity of the humerus showing fracture(s).

Left shoulder, with the offending greater tubercle/tuberosity of the humerus showing fracture(s).

Right shoulder x-ray, showing dislocation of the head of the humerus from the glenoid. Compare with above image- humerus has been shifted down. BUT no fractures, yay!

Right shoulder x-ray, showing dislocation of the head of the humerus from the glenoid. Compare with above image- humerus has been shifted down, the shoulder joint is facing you. BUT no fractures, yay!

CT scan axial slice showing my neck (on left), then scapula with fractured coracoid process ("bad") and displaced, fractured greater tubercle of humerus on right side.

CT scan axial slice showing my spine (on left), then scapula with fractured coracoid process (“Bad”) and displaced, fractured greater tubercle of humerus on right side (“V bad”).

So, that explains most of the pain I was in.

What’s amazing is that the fractures most likely occurred purely via my own uncontrolled muscle contractions. All the karate and weight-training I’d been doing certainly had made me stronger in my rotator cuff muscles, which attach to the greater tubercle of the humerus. And with inhibition of my motoneurons turned off during my seizure, and both agonist and antagonist muscles near-maximally turned on, rapid motions of my shoulders by my spasming muscles would have dislocated my shoulders and then wrenched apart some of the bony attachments of those same muscles. I’m glad I don’t remember this happening.

I had also complained of pain in my neck, so they did a CT scan and x-ray there too:

X-ray: No broken neck. This is good.

X-ray: No broken neck. This is good. Just muscle strain, which soon faded.

The left shoulder injuries created a hematoma, or mass of blood beneath my skin, and soon that surfaced and began draining down my arm (via the lymphatic system under gravity’s pull), creating fascinating patterns:

Bruises migrating; no pain associated with these, just superficial drainage of old blood.

Bruises migrating; no pain associated with these, just superficial drainage of old blood. This is tame, tame, tame compared to what my left ribcage looked like. I’ve spared you that.

But then more fundamentally there was the question of, why a seizure? With no clear warning? As I’ve explained before, I’d had a stroke ~12 yrs ago that caused a similar seizure but with no injuries to my postcranial body. So a series of MRI and CT scans ensued (the radiation I’ve had from the latter is good fodder for a superhero/villain origin tale? Marvel, I’ll await your call), and there was no clear damage or bleeding, and hence no stroke evident. Good news.

There are, however, at least two sizeable calcifications in my brain that are likely to be hardened scar tissue from my stroke. These may or may not have an identifiable affect on me or linkage with the seizure. Brain calcifications can happen for a variety of reasons, sometimes without clear ill effects.

Calcification in ?ventricle? of my cerebrum.

Calcification in parietal lobe of my cerebrum, from axial CT scan slice. But no bleeding (zone of altered density/contrast).

That is the state of the evidence. I’ve since had what semblance of a L.A. family holiday I could manage, benefitting from a touching surge of support from my family, friends and colleagues that has kept me from sinking entirely into despair and has brought quite a few smiles.

The plane flight home was tense. We were in the same seats again and one of the flight attendants recognized us and came to chat, eager to learn what had happened after we left the plane a week ago. He was very nice and the doctors had given me an “OK to fly” letter. But it was an evening flight. I needed to sleep, yet it was clear to me that sleep was no longer the fortress of regenerative sanctity that I was used to it being. Sleep had taken on a certain menace, because it was a state in which I’d now had three seizures. Warily, I drifted off to sleep after having some hearty chuckles at the ending to “22 Jump Street”. And while it was not very restful slumber, it was the friendly kind of slumber that held no convulsive violence within its embrace. We returned home safely.

In a rush, I cancelled my attendance at the Society of Vertebrate Paleontology conference this week, turning over the symposium I’d convened to honour one of my scientific heroes, biomechanist R. McNeill Alexander (who also could not attend due to ill health), to my co-convenors Eric Snively and Andreas Christian (by accounts I heard, all went well). I missed out on a lot of fun and the joy of watching 2 of my PhD students present posters on preliminary results of their research. Thanks to social media and email, however, I’ve been able to catch a lot of the highlights and excitement from that conference in Berlin.That has helped distract me somewhat from other goings-on.

Meanwhile, I’ve been resting, doing a minimal amount of catching up with work, having a lot of meetings with doctors to arrange treatment, and pondering my situation– a lot.

I know this much: I’ve had two violent seizures in a month (the previous one was milder but still bad, and not a story I need to tell here), and so I’m now an epileptic, technically. When and if I’ll have another seizure is totally uncertain, but to boost the odds in my favour I’m on anti-convulsant drugs for a long time now.

In about half of seizure cases, it’s never clear what caused the seizures. What caused my 2002 stroke is somewhat clear, but the mechanism behind that remains a mystery, and my other health problems likewise have a lot of question marks regarding their genesis and mutually causative relationships, if any. The outcome of this new development in my medical history is likely to be: “maybe your brain calcifications and scar tissue helped stimulate your new seizures, but we can’t be sure. The treatment is the same regardless: stay on anti-convulsants for a while, try going off them later, and see if seizures manifest themselves again or not.” Brains are freaking complicated; when they go haywire it can be perplexing why.

As a scientist, I thrill at finding uncertainty in my research topics because that always means there is work left to be done. But in my own life outside of science, stubborn, independent, strong-willed control freak that I can certainly be at times, I am not such a fan of uncertainty. In both cases the goal is to minimize that uncertainty by gathering more information, but in our lives we often encounter unscalable walls of uncertainty that persist because of lack of knowledge regarding a problem that vexes us, especially a medical problem. We then can feel in a helpless state, adrift on the horizon of science, waiting for explorers to push that horizon further and with it advance our treatment or at least our insight into ourselves.

When the subject of that uncertainty is not some detached, objective, unthreatening, exciting research topic but rather ourselves and our own future constitution and mortality, it thus becomes deeply personal and disconcerting. I’m grateful that I don’t have brain cancer or some other clear and present threat to my immediate vitality. Things could be a lot worse; I am here writing this blog after all. I’ll never forget now being in the ambulance and thinking “this may be the end of it all; I might not last much longer”, and choking out a farewell to my wife just in case things took a bad turn. I’m grateful for the amazing things that modern medicine and imaging techniques can do– these have saved my life so many times over, I cannot fathom how to quantify it. And I’m grateful for the people that have helped me through this so far. Fiercely independent as I may be, I can’t face everything alone.

I am reminded of words I read recently by Baruch Spinoza, “The highest activity a human being can attain is learning for understanding, because to understand is to be free.” To further paraphrase him, we love truth because it is knowledge that enables us to stay alive- without it, we are flying blind and soon will crash. With the freedom it brings, we know the landscape of our own life and where the frontiers of uncertainty lie (“here be dragons”).

here_be_dragons

The past two weeks have been horrendous for me. I’d been feeling healthy and stronger than ever in many ways, and my life as of my birthday a month ago felt pretty damn good. But now everything has come crashing down in disaster, and I have been suffering from the realization, once again, of how vulnerable I am and how little I can control, and the darkness that ushers in as the odds begin to stack up against our future lives. I am acutely aware now of where the “dragons” are.

I am taking one important step forward, though, in wresting life back onto the rails again- this week I undergo surgery to put my left shoulder back together. While that’s scary, to be sliced open and have my rotator cuff and bones carpentered back where they should be, I know I’m in good hands with a top UK shoulder surgeon and methods that are tried-and-true. The risks are small, although the recovery time will be long. There won’t be any hefting of big frozen elephant feet in my research soon, not for me, and so my enjoyable anatomy studies are going to have to change their track for coming months while I regain my strength and rely on others’ help.

(do you know the movie reference?)

(do you know the movie reference? I have a new empathy for Ash.)

Then we’re on to the frightening task of tackling the spasmodic-gorilla-in-the-room with neurologists. We’ll see where that journey leads.

One thing is certain: I’m still me and there’s still a lot of fight left in me, because I have a lot left to fight for, and people and knowledge to aid me in that fight. I can shoulder the burden of uncertainty in my life because I have all that. Off I go…

20 November UPDATE:

I’ve had surgery to put my greater tuberosity back where it belongs. Thanks to a skilled surgeon’s team, some sutures and nickel-titanium staples, I am back closer to my normal morphology and can begin recovering my (currently negligible) shoulder joint’s range of motion via some physiotherapy. Surgery went very well; I was just in hospital for ~30 hours; but the 9 days of recovery since have been brutally hard due to problems switching medications around. Today I got my stitches out and a beautiful x-ray showing plentiful healing; yay!

This is a slightly oblique anterior (front) view of my left shoulder/chest. Fracture callus means healing is working well!  Four surgical staples (bright white thingies on upper RH side of image): forever now a part of my anatomy.

This is a slightly oblique anterior (front) view of my left shoulder/chest. Fracture callus means healing is working well!
Four surgical staples (bright white thingies on upper RH side of image): forever now a part of my anatomy.

Title says it all? Sometimes a spade needs to be called a spade.

From time to time the Structure & Motion Lab at the RVC gets cool videos of animals doing different behaviours, be that slow-mo/high-speed videos, x-ray videos. motion capture or whatever. Actually, we get cool videos pretty much every day but some of them (such as a racehorse galloping on a treadmill) seem mundane to us, much as our visitors are impressed.

Here are some examples of the stuff we’ve filmed recently. It all seems to belong on this blog as an example of anatomy in motion, but has no good home here otherwise and no other cohesive threads uniting the disparate videos.

Hence the title. Enjoy!

The above two videos were made by Renate Weller, Emily Sparkes and others. Looping GIF of the last one, via Marko Bosscher:

X-Ray_Hamster

Shin-Ichi Fujiwara, myself and others made that video some years ago; research yet to be finished.

The above two high-speed videos were captured many moons ago with Alexis Wiktorowicz, Karin Jespers and others; more research yet to be finished.

Ashley Heers made this video for the “Fossil Wonderlands” documentary in 2013-14.

Check us out on BBC2 tonight in Cat Watch, with more videos!

 

Let's play find-the-spandrel!

Let’s play find-the-spandrel!

We just passed the 35th anniversary of the publication of Gould and Lewontin’s classic, highly cited, highly controversial essay (diatribe?), “The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme.” The 21st of September 1979 was the fateful date. Every PhD student in biology should read it (you can find pdfs here– this post assumes some familiarity with it!) and wrestle with it and either love it or hate it- THERE CAN BE NO MIDDLE GROUND! With some 5405 citations according to Google Scholar, it has generated some discussion, to put it lightly. Evolutionary physiologists and behaviourists who were working at the time it came out have told me stories of how it sent (and continues to send) shockwaves through the community. Shockwaves of “oh crap I should have known better” and “Hell yeah man” and “F@$£ you Steve,” more or less.

I am among those who love “The Spandrels Paper“. I love it despite its many flaws that people have pointed out to seemingly no end- the inaccurate architectural spandrel analogy, the Gouldian discursive (overly parenthetical [I’m a recovering victim of reading too much Gould as an undergrad]) writing style, the perhaps excessive usage of “Look at some classic non-scientific literature I can quote”, the straw men and so on. I won’t belabour those; again your favourite literature search engine can be your guide through that dense bibliography of critiques. I love it because it is so daringly iconoclastic, and because I think it is still an accurate criticism of what a LOT of scientists who do research overlapping with evolutionary biology (that is, much of biology itself) do.

The aspects of The Spandrels Paper that I still think about the most are:

(1) scientists seldom test hypotheses of adaptation; they are quick to label something that is useful to an animal as an adaptation and then move on after rhapsodizing about how cool of an adaptation it is; and

(2) thus alternatives to adaptation, which might be very exciting topics to study in their own right, get less attention or none.

True for #2, evo-devo has flourished by raising the flag of constraint (genetic/developmental/other factors that prevent evolution from going in a certain direction, or even accelerate it in less random directions). That’s good, and there are other examples (genetic drift, we’ve heard about that sometimes), but option #1 still often tends to be the course researchers take. To some degree, labelling something as an adaptation is used as hype, to make it more exciting, I think, in plenty of instances.

Truth be told, much as Gould and Lewontin admitted in their 1979 paper and later ones, natural selection surely forges lineages that have loads of adaptations (even in the strictest sense of the word), and a lot of useful traits of organisms are thus indeed adaptations by any stripe. But the tendency seems to be to assume that this presumptive commonality of adaptations means that we are justified to quickly label traits as adaptations.

Or maybe some researchers just don’t care about rigorous tests of adaptation as they’re keen to do other things. Standards vary. What I wanted to raise in this post is how I tend to think about adaptation:

I think adaptations are totally cool products of evolution that we should be joyous to imagine, document, test and discover. But that means they should be Special. Precious. A cause for celebration, to carefully document by scientific criteria that something is an adaptation in the strictest sense, and not a plesiomorphy/exaptation (i.e. an adaptation at a different level in the evolutionary hierarchy; or an old one put to new uses), spandrel/byproduct, or other alternatives to adaptation-for-current-biological-role.

But that special-ness means testing a hypothesis of adaptation is hard. As many authors waving the flag of The Modern Comparative Method (TMCM) have contended, sciencing truth-to-adaptationist-power by the rules of TMCM takes a lot of work! George Lauder’s 1996 commentary in the great Adaptation book (pdf of the chapter here) outlined a lengthy procedure of  “The Argument from Design“; i.e., testing adaptation hypotheses. At its strictest implementation it could take a career (biomechanics experiments, field studies, fitness measurements, heritability studies, etc.) to test for one adaptation.

Who has time for all that?

The latter question seems maladaptive, placing cart and horse bass-ackwards. If one agrees that adaptations are Special, then one should be patient in testing them. Within the constraints of the practical, to some degree, and different fields would be forced to have different comfort levels of hypothesis testing (e.g. with fossils you can’t ever measure fitness or other components of adaptation directly; that does not mean that we cannot indirectly test for adaptations– with the vast time spans available, one would expect palaeo could do a very good job of it, actually!).

I find that, in my spheres of research, biomechanists in particular tend to be fast to call things they study adaptations, and plenty of palaeontologists do too. I feel like over-usage of the label “adaptation” cheapens the concept, making the discovery of one of the most revered and crucial concepts in all of evolutionary biology seem cheapened and trite. Things that are so easy to discover don’t seem as precious. When everything is awesome, nothing is…

I’ve always hesitated, thanks in part to The Spandrels Paper’s indoctrination, from calling features of animals adaptations, especially in my main research. I nominally do study major ?adaptations? such as terrestrial locomotion at giant body sizes, or the evolution of dinosaurian bipedalism. I searched through my ~80 serious scientific papers lately and found about 50 mentions of “adapt” in an adaptationist, evolutionary context. That’s not much considering how vital the concept is (or I think it is) to my research, but it’s still some mentions that slipped through, most of them cautiously considered– but plenty more times I very deliberately avoided using the term. So I’m no model of best practice, and perhaps I’m too wedded to semantics and pedantry on this issue, but I still find it interesting to think about, and I’ve gradually been headed in the direction of aspect #2 (above in bold) in my research, looking more and more for alternative hypotheses to adaptation that can be tested.

I like talking about The Spandrels Paper and I like some of the criticism of it- that’s healthy. It’s a fun paper to argue about and maybe we should move on, but I still come back to it and wonder how much of the resistance to its core points is truly scientific. I’m entering into teaching time, and I always teach my undergrads a few nuggets of The Spandrels Paper to get them thinking about what lies beyond adaptation in organismal design.

 What do other scientists think? What does adaptation mean (in terms of standards required to test it) to you? I’m curious how much personal/disciplinary standards vary. How much should they?

For the non-scientists, try this on for size: when our beloved Sir David Attenborough (or any science communicator) speaks in a nature documentary about how the otter is “perfectly adapted” to swim after prey underwater, do you buy into that or question it? Should you? (I get documentaries pushing me *all the time* to make statements like this, with a nudge and a wink when I resist) Aren’t scientists funny creatures anyway?

MysteryCT12
Here’s an image that struck me as cool and possibly perplexing. And so we have another Mystery Anatomy post! Brought to you by some free time on my current trip to Gondwanaland.

Stomach-Churning Rating: 1/10; simple CT scan slice… of something.

Mystery Anatomy 2014same rules as before; remember that the scoreboard has been reset.

Identify the animal in the CT slice shown above, as specifically as you can. No special rules.

Difficulty: Plenty.

Begin!

 

I’ll let the poll (prior post) run for a while but as it winds down I wanted to explain why I posted it:

In the past, I’ve often run into scientists who, when defending their published or other research, respond something like this:

“Yeah those data (or methods) might be wrong but the conclusions are right regardless, so don’t worry.”

And I’ve said things like that before. However, I’ve since realized that this is a dangerous attitude, and in many contexts it is wrong.

If the data are guesses, as in the example I gave, then we might worry about them and want to improve them. The “data are guesses” context that I set the prior post in comes from Garland’s 1983 paper on the maximal speeds of mammals– you can download a pdf here if this link works (or Google it). Basically the analysis shows that, as mammals get bigger, they don’t speed up as a simple linear analysis might show you. Rather, at a moderate size of around 50-100kg body mass or so, they hit a plateau of maximal speed, then bigger mammals tend to move more slowly. However, all but a few of the data points in that paper are guesses, many coming from old literature. The elephant data points are excessively fast in the case of African elephants, and on a little blog-ish webpage from the early 2000s we chronicled the history of these data– it’s a fun read, I think. The most important, influential data plot from that paper by Garland is below, and I love it– this plot says a lot:

Garland1983

I’ve worried about the accuracy of those data points for a long time, especially as analyses keep re-using them– e.g. this paper, this one, and this one, by different authors. I’ve talked to several people about this paper over the past 20 years or so. The general feeling has been in agreement with Scientist 1 in the poll, or the quote above– it’s hard to imagine how the main conclusions of the paper would truly be wrong, despite the unavoidable flaws in the data. I’d agree with that statement still: I love that Garland paper after many years and many reads. It is a paper that is strongly related to hypotheses that my own research seeks out to test. I’ve also tried to fill in some real empirical data on maximal speeds for mammals (mainly elephants; others have been less attainable), to improve data that could be put into or compared with such an analysis. But it is very hard to get good data on even near-maximal speeds for most non-domesticated, non-trained species. So the situation seems to be tolerable. Not ideal, but tolerable. Since 1983, science seems to be moving slowly toward better understanding of the real-life patterns that the Garland paper first inferred, and that is good.

But…

My poll wasn’t really about that Garland paper. I could defend that paper- it makes the best of a tough situation, and it has stimulated a lot of research (197 citations according to Google; seems low actually, considering the influence I feel the paper has had).

I decided to do the poll because thinking about the Garland paper’s “(educated) guesses as data” led me to think of another context in which someone might say “Yeah those data might be wrong but the conclusions are right regardless, so don’t worry.” They might say it to defend their own work, such as to deflect concerns that the paper might be based on flawed data or methods that should be formally corrected. I’ve heard people say this a lot about their own work, and sometimes it might be defensible. But I think we should think harder about why we would say such things, and if we are justified in doing so.

We may not just be making the best of a tough situation in our own research. Yes, indeed, science is normally wrong to some degree. A more disconcerting situation is that our wrongs may be mistakes that others will proliferate in the future. Part of the reasoning for being strict stewards of our own data is this: It’s our responsibility as scientists to protect the integrity of the scientific record, particularly of our own published research because we may know that best. We’re not funded (by whatever source, unless we’re independently wealthy) just to further our own careers, although that’s important too, as we’re not robots. We’re funded to generate useful knowledge (including data) that others can use, for the benefit of the society/institution that funds us. All the more reason to share our critical data as we publish papers, but I won’t go off on that important tangent right now.

In the context described in the latter paragraph and the overly simplistic poll, I’d tend to favour data over conclusions, especially if forced to answer the question as phrased. The poll reveals that, like me, most (~58%) respondents also would tend to favour data over conclusions (yes, biased audience, perhaps- social media users might tend to be more savvy about data issues in science today? Small sample size, sure,  that too!). Whereas very few (~10%) would favour conclusions, in the context of the poll. The many excellent comments on the poll post reveal the trickier nuances behind the poll’s overly simplistic question, and why many (~32%) did not favour one answer over the other.

If you’ve followed this blog for a while, you may be familiar with a post in which I ruminated over my own responsibilities and conundrums we face in work-life balance, personal happiness, and our desires to protect ourselves or judge/shame others. And if you’ve closely followed me on Twitter or Facebook, you may have noticed we corrected a paper recently and retracted another. So I’ve stuck by my guns lately, as I long have, to correct my team’s work when I’m aware of problems. But along the way I’ve learned a lot, too, about myself, science, collaboration, humanity, how to improve research practice or scrutiny, and the pain of errors vs. the satisfaction of doing the right thing. I’ve had some excellent advice from senior management at the RVC along the way, which I am thankful for.

I’ve been realizing I should minimize my own usage of the phrase “The science may be flawed but the conclusions are right.” That can be a more-or-less valid defence, as in the case of the classic Garland paper. But it can also be a mask (unintentional or not) that hides fear that past science might have real problems (or even just minor ones that nonetheless deserve fixing) that could distract one away from the pressing issues of current science. Science doesn’t appreciate the “pay no attention to the person behind the curtain” defence, however. And we owe it to future science to tidy up past messes, ensuring the soundness of science’s data.

We’re used to moving forward in science, not backward. Indeed, the idea of moving backward, undoing one’s own efforts, can be terrifying to a scientist– especially an early career researcher, who may feel they have more at risk. But it is at the very core of science’s ethos to undo itself, to fix itself, and then to move on forward again.

I hope that this blog post inspires other scientists to think about their own research and how they balance the priorities of keeping their research chugging along but also looking backwards and reassessing it as they proceed. It should become less common to say “Yeah those data might be wrong but the conclusions are right regardless, so don’t worry.” Or it might more common to politely question such a response in others. As I wrote before, there often are no simple, one-size-fits-all answers for how to best do science. Yet that means we should be wary of letting our own simple answers slip out, lest they blind us or others.

Maybe this is all bloody obvious or tedious to blog readers but I found it interesting to think about, so I’m sharing it. I’d enjoy hearing your thoughts.

Coming soon: more Mystery Anatomy, and a Richard Owen post I’ve long intended to do.

A short post that guest-tweeting at the  Biotweeps account on Twitter got me thinking about– featuring a poll.

Imagine this: two scientists (colleagues, if you’re a scientist) are arguing thusly. Say it’s an argument about a classic paper in which much of the data subjected to detailed statistical analyses are quantitative guesses, not hard measurements. This could be in any field of science.

Scientist 1: “Conclusions are what matter most in science. If the data are guesses, but still roughly right, we shouldn’t worry much. The conclusions will still be sound regardless. That’s the high priority, because science advances by ideas gleaned from conclusions, inspiring other scientists.”

Scientist 2: “Data are what matter most in science. If the data are guesses, or flawed in some other way, this is a big problem and scientists must fix it. That’s the high priority, because science advances by data that lead to conclusions, or to more science.”

Who’s right? Have your say in this anonymous poll (please vote first before viewing results!):

link: http://poll.fm/4xf5e

[Wordpress is not showing the poll on all browsers so you may have to click the link]

And if you have more to say and don’t mind being non-anonymous, say more in the Comments- can you convince others of your answer? Or figure out what you think by ruminating in the comments?

I’m genuinely curious what people think. I have my own opinion, which has changed a lot over the past year. And I think it is a very important question scientists should think about, and discuss. I’m not just interested in scientists’ views though; anyone science-interested should join in.

[This is the original, unedited text of my shorter, tighter (and I think actually better) News & Views piece for Nature, on the paper described below)

Ambitious experimental and morphological studies of a modern fish show how a flexible phenotype may have helped early “fishapods” to make the long transition from finned aquatic animals into tetrapods able to walk on land.

Stomach-Churning Rating: 1/10. Cute fish. Good science. Happy stomachs!

Photo by Antoine Morin, showing Polypterus on land.

Photo by Antoine Morin, showing Polypterus on land.

Napoleon Bonaparte’s military excursions into Egypt in 1798-1799 led a young French naturalist, Ètienne Geoffroy Saint-Hilaire, to cross paths with a strange fish that had paired lungs and could “walk” across land on its stubby, lobelike fins. In 1802, he dubbed this fish “Polyptère bichir”1, today known as the Nile bichir, Polypterus bichir La Cepède 1803. The bichir’s mélange of primitive and advanced traits helped to catapult Geoffroy into scholarly conflict with the reigning naturalist Georges Cuvier back in France and to establish Ètienne as a leading anatomist, embryologist and early evolutionary researcher of repute even today2. Now, on their own excursion under the very “evo-devo” flag that the discoverer of Polypterus helped raise, Canadian scientists Standen et al.3 suggest how the remarkable plasticity of the skeleton of Polypterus (the smaller west African relative of P. bichir, P. senegalus or “Cuvier’s bichir”) reveals a key part of the mechanism that might have facilitated the gradual transition from water to land and thus from “fishapods” to tetrapods (four-limbed vertebrates).

In a bold experiment, the authors raised 149 young bichirs on land and in water for eight months, then studied how they moved on land vs. in water, and also how the ultimate shape of the skeletal elements of the paired front fin bases differed between the land- and water-raised bichirs. Standen et al.3 discovered that both the form and function of the fins’ foundations transformed to better satisfy the constraints of moving on land. Land-acclimated bichirs took faster steps on land, their fins slipped across the substrate less, they held their fins closer to their body, their noses stayed more aloft and their tails undulated less, with less variable motions overall—behaviours that the authors had predicted should appear to enhance walking abilities on land. In turn, the bones of the neck and shoulder region altered their shape to produce a more mobile fin base with greater independence of fin from neck motion, along with improved bracing of the ventral “collarbone” region. These environmentally-induced traits should have fostered the locomotor changes observed in “terrestrialized” fish and aided the animals in resisting gravity, and they represent a common biological phenomenon termed developmental plasticity4,5. Interestingly, the land-reared fish could still swim about as well as the wholly aquatic cohort, so there was not a clear trade-off between being a good swimmer and a good walker, which is surprising.

Considered alone, the developmental plasticity of bichir form and function shows how impressive these amphibious fish are. But Standen et al.’s study3  ventured further, to apply the lessons learned from bichir ontogeny to a phylogenetic context and macroevolutionary question. The phenotypic plasticity during bichir development, they infer, could have been harnessed during the evolutionary transformation of fins for swimming into limbs for walking, in the “fishapod” ancestors of tetrapods. Indeed, bichirs are close to the base of the family tree of fishes6, and other living relatives of tetrapods have reduced or lost their fins (lungfishes) or adapted to strange deep-sea swimming lifestyles, never walking on land (coelacanths). Thus perhaps bichirs and the “fishapod” lineage share what Geoffroy would have called “unity of type”, today termed homology, of their developmental plasticity in response to a land environment. Surveying the fossil record of early “fishapods” and tetrapods, Standen et al.3 found that the macroevolutionary changes of neck and shoulder anatomy in these gradually more land-adapted animals parallel those they observed in terrestrialized Polypterus, providing ancillary support for their hypothesis.

A further test of the application of Polypterus’s plasticity to fossil tetrapods is naturally difficult. However, the “fishapod” lineage has some exceptional examples of fossil preservation. With sufficient sample sizes (e.g. fossil beds that reveal growth series, such as the Late Devonian Miguasha site in Canada7) and palaeoenvironmental gradients in fish or tetrapods, one could imagine performing a rigorous indirect test. Even small samples could be helpful– for example, the early tetrapod Ichthyostega exhibits some developmental changes in its forelimb suggesting that it became more terrestrial as it grew, whereas the related Acanthostega does not evidence such changes8– this hints at some developmental plasticity in the former animal.

During the Devonian period (~360-420 million years ago), were the “fishapod” ancestors of tetrapods floundering about on land now and then, gradually shifting from anatomy and behaviours that were more developmentally plastic (as in bichirs) to ones that were more canalized into the terrestrialized forms and functions that more land-adapted tetrapods retained? An attractive possibility is that the developmental plasticity could have led to fixation (reduction of plasticity), an evolutionary phenomenon called genetic assimilation, which another intellectual descendant of Geoffroy, Conrad Hal Waddington, promoted from the 1950s onwards9, a concept that now enjoys numerous cases of empirical support10 that this one may eventually join.

The nature of the genetic and developmental mechanism that bichirs use to achieve the observed developmental plasticity is still unclear. If it has a high enough degree of heritability, then it could be selected for in cross-generational experiments with bichirs. With sufficient time and luck raising these unusual fish, the hypothesis that their plastic response to a terrestrial environment can become genetically assimilated could be directly tested. This study could thus become an epic exemplar of how genetic assimilation can contribute not only to microevolutionary change but also to major macroevolutionary events, as was presciently suggested in a seminal review of developmental plasticity4.

This genetic assimilation is the Polypterus study’s reasonable speculation, and one that Geoffroy likely would have applauded, all the more for involving his beloved bichirs. Much as Napoleon’s landfall in Egypt was not a lasting success, bichirs never left wholly terrestrial descendants despite their malleable locomotor system. But the same type of plastic developmental mechanism that bichirs use today to make tentative, floppy incursions of the terrestrial realm might have been harnessed by our own “fishapod” forebears, leaving a far more revolutionary dynasty upon the Earth.

 

References

  1.  Geoffroy, E. (1802). Histoire naturelle et description anatomique d’un nouveau genre de poisson du Nil, nommé polyptère. Annales du Muséum d’Histoire Naturelle 1:57-68.
  2. Le Guyader, H., & Grene, M. (2004) Geoffroy Saint-Hilaire: A Visionary Naturalist. Univ. Chicago Press.
  3. Standen, E. M., Du, T. Y., & Larsson, H. C. E. (2014). Developmental plasticity and the origin of tetrapods. Nature, published online.
  4. West-Eberhard, M. J. (1989). Phenotypic plasticity and the origins of diversity. Annual Review of Ecology and Systematics 20:249-278.
  5. Pigliucci, M., Murren, C. J., & Schlichting, C. D. (2006). Phenotypic plasticity and evolution by genetic assimilation. Journal of Experimental Biology 209(12):2362-2367.
  6. Near, T. J., Dornburg, A., Tokita, M., Suzuki, D., Brandley, M. C., & Friedman, M. (2014). Boom and bust: ancient and recent diversification in bichirs (Polypteridae: Actinopterygii), a relictual lineage of ray‐finned fishes. Evolution 68:1014-1026.
  7. Cloutier, R. (2013). Great Canadian Lagerstätten 4. The Devonian Miguasha Biota (Québec): UNESCO World Heritage Site and a Time Capsule in the Early History of Vertebrates.Geoscience Canada40:149-163.
  8. Callier, V., Clack, J. A., & Ahlberg, P. E. (2009). Contrasting developmental trajectories in the earliest known tetrapod forelimbs.Science324:364-367.
  9. Waddington, C. H. (1953). Genetic assimilation of an acquired character. Evolution 7:118-126.
  10. Crispo, E. (2007). The Baldwin effect and genetic assimilation: revisiting two mechanisms of evolutionary change mediated by phenotypic plasticity. Evolution 61:2469-2479.
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