Idiocy beyond belief; SHARKS DON’T HAVE WEBBED FEET!

26 07 2007

Update: Many thanks to Chris for reminding me of one of my most favorite SNL sketches;

In March I blogged about a Malaysian woman who claimed to have found a shark with webbed feet, although anyone with even a cursory knowledge of shark anatomy could see that the “webbed feet” were really the paired male reproductive organs indicative of sharks known as claspers. [Not that I expect others to have this understanding, but rather that it’s obvious if you do have that knowledge] Now the story has resurfaced, probably due to it being featured on this blog, and plenty of folks are blathering away about how the shark does or does not support evolution. Apparently this has become the evolution equivalent of the New Zealand “plesiosaur” mix-up, at least among evolution supporters who are woefully uninformed. I was content to keep my mouth shut about this issue, just letting the issue fade away into obscurity, but then I received this comment from “bnutler”;

yeah but the first feet probably were not “feet” either. the process of evolution involves mutations, and this is an example of a mutation could have lead to feet. it would be unintelligent to assume that the first feet were actually intended to be used in the way land animals use them. It would be even more unintelligent to think that something hand designed everything on earth..

This is why the evolution debate frustrates me; even amongst people who support evolution, understanding can be absent. Tetrapods did not evolve their limbs from paired claspers; the bones of our limbs (and the limbs of our ancestors all the way down to the first tetrapods) are homologous with those of fish belonging to the Class Sarcopterygii, an extant example being the Coelacanth. The living coelacanth is not ancestral to us however, as it is too young in age and belongs to the wrong group. The group that led to tetrapods were the Rhipidistia, a subgroup of the Sarcopterygiian fish, and it was the bones in the fleshy fins of these animals that gave rise to the tetrapod limb. Indeed, even though living coelacanths are not our ancestors, they give us a clue as to how fins could have been modified to limbs; in addition to having the proper structure, they can “walk” through the water using their fins, moving them independently. Epaulette Sharks can walk along the bottom as well, using their pectoral and pelvic fins, although their skeletons are a long way from being anything close to that of the Rhipidistians.

Anyway, shark claspers are only found in male sharks, and although they are supported by cartilage they are not otherwise connected to the spine or skeleton. Thus, in order for claspers to be the antecedents to feet, they’d have to become present in all sharks of that species (including females), somehow change their musculature, change their skeletal structure, allow attachment to the rest of the skeleton, and also duplicate themselves in the front part of the skeleton and undergo the same changes (unless you’re going to argue that claspers made the back feet and pectoral fins made the front feet). This is obviously ridiculous, and furthermore what is being suggested by bnutler is a major saltation; a major change from having paired reproductive organs to having feet overnight (it would bring a new meaning to foot-fetishes, I’ll tell you that much). This isn’t even mentioning all the other physiological changes that would have to occur in the body (which we have evidence for in tetrapod evolution, especially in the spine and skull), and overall sharks are an extremely poor candidate for tetrapod ancestors, then or now.

I don’t mean to be so overly harsh, but I simply cannot believe all the back and forth over this picture. If anything, it’s a lesson that it’s not simply enough to get people to agree that evolution has occurred; if they do not understand it no good will come from it. Without understanding, people will have “faith” in evolution rather than knowledge of it, and even if a school isn’t teaching ID or creationism it doesn’t mean that they’re teaching evolution accurately (or at all!). I especially liked bnutler’s ending sentences, wherein he (she?) insinuates that because I don’t agree that the shark claspers are really freaky feet, I must believe that limbs were “intelligently designed” or created for a purpose. I guess they don’t stop by here much, huh?

[Update: Changed some of the language as it was a bit harsh; such comes from blogging out of frustrations. Also I was writing feverishly using the Mac at home, which does not highlight spelling/grammatical errors, which I have now fixed as well.]


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26 07 2007
Chris Harrison

[Scene: A New York apartment. Someone knocks on the door.]
Woman: [not opening the door] Yes?
Voice: (mumbling) Mrs. Arlsburgerhhh?
Woman: What?
Voice: (mumbling) Mrs. Johannesburrrr?
Woman: Who is it?
Voice: [pause] Flowers.
Woman: Flowers for whom?
Voice: [long pause] Plumber, ma’am.
Woman: I don’t need a plumber. You’re that clever shark, aren’t you?
Voice: [pause] Candygram.
Woman: Candygram, my foot. Get out of here before I call the police. You’re the shark, and you know it.
Voice: I’m only a dolphin, ma’am.
Woman: A dolphin? Well…okay. [opens door]
[Huge latex and foam-rubber shark head lunges through open door, chomps down on woman’s head, and drags her out of the apartment, all while the Jaws attack music is playing.]

: )

26 07 2007
david

I agree that plenty of cre-evo threads descend into two people arguing about each others miss-interprations of how evolution goes BUT; It doesn’t seem to me like this guy is arguing claspers are what gave rise to feet so much as for a more general acceptance that there is contingency in evoluton.* That if this were a new mutation it might be the sort of thing that could later be seized upon as the raw material for a new adaptation (like bony fins being later used to support weight in the water then on the land). Hand wavey and a little bit strange but not quite as dead wrong as your interpretation (though I have to admit now I’m a little lost somwhere in the logic i contructed for bnutler)

* which sets him appart from most well meaning missinformed crusaders for evolution who tend to be ultra adaptationsits.

26 07 2007
laelaps

David; Perhaps that’s your reading, but I took the sentence ” the process of evolution involves mutations, and this is an example of a mutation could have lead to feet.” as 1) the idea that the sharks claspers were really a mutation, 2) that it was a saltational change, and 3) that such a mutation “could have lead [sic] to feet.” This reflects that the argument of “bnutler” was baseless because not only did they misidentify normal organs as special salatations, but they still maintained that the claspers could have evolved into feet. While they might be correct in an especially general sense (i.e. random mutation = variation or phenotypic change that evolution can work on), I don’t think I was unreasonable in my interpretation of what was said. If I’m entirely wrong, bnutler is welcome to correct me and I’ll amend my analysis, of course.

And Chris; I love the Land Shark sketch, thanks for putting that up (it definitely made me laugh. Now I’ll have to find the YouTube video…)

27 07 2007
Chris Harrison

I’m trying to wrap my head around the size of the mutation(s) needed to go from leglessness –> two fully functional hind legs.
I’d be the hopeful monster of all hopeful monsters!

27 07 2007
laelaps

Chris; especially legs from reproductive organs. You’d need a pretty sophisticated baculum or something to acheive that, although if your parts were being turned into legs I don’t know how you’d reproduce and pass on those changes (it’s be a rather disconcerting macromutation, to say the least)

27 07 2007
Chris Harrison

I’d almost be radical enough to make you believe in an intelligent designer!

27 07 2007
Oldfart

Don’t get all hyper excited about this. You are in danger of becoming an effete intellectual snob. To counter that, since you are still in school, I suggest you take the original article around to students in the physics and chemistry departments and see how well they can identify those appendages. Then take it out on the street amongst all the townies and ask them. The fact is that not everyone is an expert in shark sex. Nor can you expect them to be. If it was that easy to acquire the education you have earned, everyone would be doing it. If you are going to maintain and expand this attitude towards the “great unwashed”, you are not going to serve your specialty very well at all.

27 07 2007
laelaps

Perhaps I was a little harsh in my initial post, and the old adage of catching more flies with honey than vinegar holds, but I don’t think I was being overly unreasonable. I don’t expect everyone to be an expert on shark anatomy or shark sex, but I would like to think that if people saw a fantastical image of a supposed shark with “feet” they’d think twice about it first. Beyond problems with public education (and it’s failure to teach critical thinking skills), I just can’t understand why people don’t use their brains. If this was some super-obscure topic, I could understand why people didn’t get it, but it seems that all too many people took the story at face value as “true” (much like the Oscar the cat story yesterday) without looking further into it. We can’t blame everything on the schools; people either aren’t thinking or expecting the mass media to think for them, and the public’s lack of interest in terms of science & critical thinking is disturbing.

You’re right that I should be careful not to look down my nose at other people; I don’t wish to become a scientific snob, but this case got on my nerves for a few reasons. 1) People accepted the story at face value and starting arguing evolution v. creation on an unsubstantiated, short, old, article, although some did look into it further (hence the links that brought it to my attention). 2) When I went on the post to try and link back to my initial writings on the subject, revealing what was really going on, it was removed for no apparent reason. 3) Even after some people read about the truth behind this story, they still maintained that I must be wrong about it, preferring the more fanciful notion to the scientific explanation.

I don’t consider the people I mentioned about to be “lesser” or “worse” than I am, but my frustration stems from the lack of critical thinking. There are lots of smart people out there, lots of people who could do a lot of good and foster a lot of understanding if they really tried, but I feel that all too many people are intellectually lazy, and I get frustrated when not only the public education system fails students, but also when people maintain fanciful explanations even when they’re presented with the right answer. I went a bit off the handle in the post, but in the vast majority of my writing I try to make science as interesting and accessible as I can; I want people to understand science, but some initiative has to come from them, too.

27 07 2007
Oldfart

I apologize for getting “snippy”. I’m not called Oldfart for nothing….
After months of beating my head against a right wing wall of ignorance I have discovered that (1) they don’t listen and (2) the left wing has their own wall of ignorance. I recently received an email idolizing some sheriff in Arizona who is supposed to be really tough on prisoners. The facts didn’t bear that out so I did a little essay on him and sent it back. The result……….dead silence. A few weeks or months from now I will get the same email again. The same is true for the creationists vs. the evolutionists. The vast majority of the people fighting this fight are “believers” not scientists. When the creationists come out with something ridiculous about evolution the quickest counter punchers are going to be the evolutionists (for lack of a better term). Most of the evolutionists (such as myself) are people who were “taught” evolution in high school and continued their belief later on in life but who are not technically proficient in the technical details of the science of evolution. You use terms in your response to the whole issue that are unknown to me and I’m on your side. (What the hell is a baculum???) I have trouble understanding Afarensis sometimes also when he waxes technical. That is not your fault and not his fault. Keep it up. Maybe I’ll actually learn something. Meantime, there are limits to critical thinking. Sharks should not have legs……..but…….most of us know very little about sharks and even less about mutations.

27 07 2007
laelaps

Thanks for the honest response and breath of fresh air. The trouble with blogs (or at least mine) is that I write what is essentially going on in my head, and not everything in my head merits being included for one reason or another. Still, I should do my best to take what I’ve thought as the “Carl Sagan approach” to talking about science; making it accessible but not being demeaning. People’s beliefs may be wrong, but they are often sincerely held (although I make an exception for the Discovery Institute, hah).

And thanks for pointing out my need to be clearer when I use unfamiliar terms; I’ve had other people I know personally tell me that my blog looks interesting, but some of the words want to make them run away. Perhaps this can’t be helped (at least in terms of fear of technical jargon), but I should at least try harder to explain things that are unfamiliar. And to answer your quesiton, a baculum is a “penis bone” found in most mammals (as far as primates go, only us and one or two species or monkey lack one). It’s a support structure that helps maintain rigidity, although it seems that evolution has solved the problem another way for humans.

27 07 2007
Kevin Z

Certainly science communication is of utmost importance in this modern world. I would just like to point out that, in my own opinion, I feel it is wrong to refer to evolution as a belief. A belief connotates a sort of “faith” in something. As Mark Twain said “Faith is believing what you know ain’t so”. We actually do know some things about the several theories of evolution. These are theories, such as natural selection, genetic drift etc. that have supporting empirical evidence. Stating evolution as a belief puts it on par with religion or philosophy in general. Which, almost by definition, can’t be supported empirically but can only inferred, such as the rationalist approach. Rationalism argues that everything doesn’t need to be proven, but can be demonstrated by logic. Of course, this doesn’t mean one’s logic is always valid…

27 07 2007
laelaps

I agree Kevin; that’s why I try to be very careful not to say “believe in evolution” (I try to use terms like “agree” or “recognize” instead; I also abhor the term “Darwinism”). I think that’s the major problem we’re having with evolution these days; everyone’s heard of it, but I would wager that not too many people understand it outside of the concept of “change over time” (the “fact” of evolution), the theories of evolution being mostly unknown by the scientifically uninitiated. Hopefully I’ll be able to change some of that via this blog, but I imagine most people who will agree with me are already inclined to do so.

28 07 2007
Oldfart

Very treacherous ground. The average creationist and evolutionist “believes” because they do not have that sophisticated grounding in the technical science. And scientists, as a rule, “believe” in the scientific method. When I say I believe in evolution I really mean I believe in the application of logic and the scientific method and the reams of data that support the conclusions of evolutionists. Since I am not well educated in this matter, I “believe” or “trust” the researchers. It is not uncommon for my right wing friends (??) to accuse me of worshiping godless science. If you understand what I am struggling to say here and know of any books on the subject, please let me know.

28 07 2007
laelaps

Indeed, “believe” can be a tricky term, but I generally know what people mean when they say they “believe” in evolution; it’s not much different from saying “I believe that the earth will keep rotating in orbit as it has so the sun appears to come up in the morning.” (not the most comfortable statement, but more “accurate” than sunrise, I suppose). Part of the problem is the language of science and it’s need to be tentative; anything worth saying usually takes a long time to say, or at least requires a little bit of explanation. That’s why “Gish Gallop” in creationism (spouting off lots of kooky claims in succession really fast) seems to be so effective; it appeals to belief without having to explain much of anything at all.

I can’t think of any books of the top of my head that address the issue of explaining the “belief” or “trust” in science, and while I know what you mean when you say “believe in evolution,” I try to discourage its use because the term “believe” can be easily misunderstood/misconstrued. The way you explained it (as in trusting the process of science which requires observation, testing, revision, peer-review, and an overall cumulative build up of understanding vs. dogmatism) seems pretty good, but I know that many conservatives or fundamentalists will be unsatisfied with such an answer because you’re putting the “knowledge of man above the wisdom of God,” so you just can’t win. My usual response to this is that if we knew nothing of the Bible, God’s intervention in the natural world should be more than apparent, but over the past several centuries especially we’ve found that this is not the case; nature defies the contradictory Genesis stories, and unless one takes a very liberal or allegorical standpoint, what we see in nature and Genesis as a historically-accurate piece of literature cannot be reconciled. This is counter to what we’re told to expect in the Bible, even the verses where we’re told the whole of Creation testifies to God’s work, and over time creationists have softened their positions and had to change their views to acknoweldge science (not so long ago speciation was considered not to occur, fossils being “tricks of the Devil” meant to confuse or mislead those uppity scientists, and now creationists recognize fossils are real and that natural selection/speciation does occur, even though they go to even greater lengths to try and fit this into their interpretation of the Bible).

Anyway, while I read it about this time last year and not since, Niles Eldredge’s book The Triumph of Evolution and the Failure of Creationism is a good primer for this debate, especially since the last chapter deals with evolution as fact and theory, as well as the fact that evolution is not a belief system (not should it be one). It might not be exactly what you’re looking for, but it’ll probably help a great deal.

Anyway, I “believe” and “trust” researchers too; as a student I can’t go out and do all the experiments I would like, and so I have to rely on various books and papers. The advantage, however, is that each of these (in most cases anyway) had to undergo peer review, and not all scientists agree on any given issue; I have the ability to look at other perspectives on the same issue, and even bring in research from other fields that might be related but were not necessarily considered. There’s an overall cumulative effect where intertwining modes of evidence are required for theories to stand; without agreement from geology, biology, and even chemistry & physics, evolution simply could not stand, but it’s strength is that everything from the ages of sediments & paleontology to cell biology and studies of disease confirm evolution; the reality of it is inescapable.

I’m sorry to have rambled on for so long, but it is indeed difficult to be short/clear without using some terms that might easily be misunderstood. Time and attention are precious commodities, and part of the problem with the understanding of science is that it requires both. You obviously are willing to put in that time and attention, but those who are not (those who would, as Stephen Colbert would put it, go with their “gut” rather than their brain) will have a hard time understanding anything beyond the superficial. This is the battle that must be fought (and why I wrote the initial post that started this thread in the first place), and it is something that is exceedingly hard to resolve. If I think of any other resources outside of Eldredge’s book, I will certainly let you know (Ken Miller’s Finding Darwin’s God might be a good resource for you as well, even if Miller does play “God of the Gaps” towards the end in terms of physics).

2 09 2007
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[…] See also, Idiocy beyond belief; SHARKS DON’T HAVE WEBBED FEET! […]

21 02 2010
John

Basically all you’ve done is erected a rather large straw man argument. At no point did the person claim that this mutation is what lead to tetrapod’s feet.

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