Category Archives: Evolution

Creationist Lawyers, Defenders of Evolution?

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I recently crossed swords on X with whoever (is that you Casey?) runs the Intelligent Design The Future account, a mouthpiece, pun intended, of the Discovery Institute’s Center for Science and Culture, over the spectacle of Lawyers pontificating on scientific subjects.

Here’s how it went:

IDF: In this new interview, an attorney evaluates the evidential strength of the arguments for intelligent design.

Me: Why not ask an electrician or an office manager? Lawyers don’t have any training, as lawyers, in evaluating scientific issues.

IDF: You miss the point of connection. Lawyers don’t need to be trained specifically in scientific matters in order to apply their training in evaluating evidence for scientific claims. In addition, they also have skill in making complex ideas easier to understand.

Me: No, I understand the rhetorical point you’re trying to make, I simply reject it as being merely that, rhetoric. Lawyers are advocates who operate under very different rules than those of scientists. I could go on but I think Genie Scott did a better job than I could in a piece she wrote in 1993 in response to similar arguments made by Phillip Johnson in his book Darwin on Trial (1991) and I would direct those who are interested to read that: Darwin Prosecuted: Review of Johnson’s Darwin on Trial by Eugenie Scott

This little exchange got me thinking.

Creationist lawyers like to style themselves as noble truth-seeking prosecutors working tirelessly to indict the perfidious theory of evolution (or Charles Darwin etc.), for being fraudulent and leading the innocent astray.

But that’s not what they are.

They’re not prosecutors at all. They’re defense attorneys —and not particularly ethical ones— working on behalf of a client who never hired them and would prefer they stop talking: evolution itself (and every other science rejected by creationists).

Now, stay with me here.

Evolution (and I will focus on that since it is my forte) is guilty. Guilty as sin. The evidence against it is overwhelming.  There’s the testimony of the rocks (my apologies to Hugh Miller 1802-1856) i.e. the fossil record, genetics, comparative anatomy, comparative embryology, systematics, biogeography. Every witness for the prosecution points the same way and delivers the same verdict:

Guilty beyond a reasonable doubt — of being the best scientific explanation for the change and diversification of life on Earth through time.

Enter the defense: the creationist attorneys.

They’ll argue almost anything —no matter how absurd or misleading— to get evolution off the hook. They endlessly try to poke superficial holes in the insurmountable evidence again their unwilling client.

They argue that we should ignore the smoking gun of reliable forensic evidence against evolution in favor of hearsay testimonials in ancient texts that an “intelligent designer” (wink, wink) did it through some unknown and unknowable process, for reasons, and in a manner, known only to itself.

And they’ll denounce as “unfair” and “unjust” the scientific rules of evidence, such as a reliance on methodological naturalism, for disallowing their preferred theory of the “crime”, “God did it”, due to a lack of testability.

Sorry, creationist lawyers, only two explanations consistent with the evidence:

A) Evolution really did it.

B) Or God has gone to extraordinary lengths to stage a cosmic frame-up so perfect that mere mortals cannot hope to see through it. Is that the story you want to go with?

Of course, none of their machinations have a prayer of working on a jury of scientific peers, but this is not the true target of creationist lawyers, rather their rhetoric is aimed at two other groups. 1) Those unfamiliar with either the workings of science or the particulars of the evidence in question that they hope to sway to their cause and more importantly, 2) those that care not about science or the evidence, who are already convinced of evolutions innocence and wish to have their prejudices reinforced.

But in all seriousness, history has shown repeatedly that lawyers taking up the antievolution cause get things just as wrong as creationists from other backgrounds. If lawyers really had some special insight into this subject, then history should reflect that, it doesn’t.

My thanks to Wesley Elsberry for some comments and suggestions.

Ken Ham posts dishonestly edited and out of context quotation

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I know, “Dog Bites Man”, but I still feel whenever creationist are caught dishonestly misrepresenting the words of others it should be pointed out and documented.

In this case Ken Ham, founder CEO of the young Earth creationist (YEC) organization Answers in Genesis posted to his X account the following:

Is this high school biology textbook definition of science a scientific one?

“Restrict science to a search for natural causes for natural phenomena. Supernatural explanations of natural events are simply outside the bounds of science.”

In other words, “science” (which really means “knowledge”) cannot allow the supernatural. Thus, by this definition, God and his Word are eliminated.

But that’s not a scientific statement—it’s a religious one. Yes, religion is in every single classroom. There’s no avoiding it, and parents must be aware of this and work hard to combat it with truth.

He gives no citation other than a vague reference to a “high school biology textbook”. I was immediately suspicious about the context of this quote, wondering if the original would explain why science was limited to natural explanations for natural phenomena, something that Ham and other creationists avoid like the plague (more on this below).

So I started searching the web for the quote as Ham presented it and initially couldn’t find anything, deepening my suspicions. So I broke the quote down into individual sentences and low and behold a link popped up to the quote coming from an online biology textbook Meridian Technical Charter High School in Meridian, Idaho. And shocker of all shocks my suspicion about the context turned out to be warranted.

So I hopped on to X and replied to Mr. Ham with the following (red text not in original reply):

Oh, look Ken using dishonestly edited and out of context quotations… I am shocked, shocked I tell you.

Here is the full quote, Ken’s quoted parts bracketed ***thusly*** (red text not in original response):

>>The Limitations of Science
Science is powerful, but limited in the kinds of questions it can help answer. Science requires repeatable observations and testable hypotheses. These standards ***restrict science to a search for natural causes for natural phenomena.*** For example, science can neither prove nor disprove that unobservable or supernatural forces cause storms, rainbows, illnesses, or cures of disease. ***Supernatural explanations of natural events are simply outside the bounds of science.*** There is no way to show that such hypotheses are false.<<

Just leave out the parts that tell us why supernatural claims like “God did it” are not scientific, *because they are not testable*. And Ken has the audacity to talk about “truth”.

Source of the quote: bodell.mtchs.org/OnlineBio/BIOC    

So he provides no citation, no context, and not even any ellipses (…) indicating that the sentences were not contiguous in the original source. As I indicated in my response to him, he has a lot of gall to speak of “truth” when pulling these sorts of shenanigans.  

Here is some more relevant context from the textbook, specifically regarding theories like evolution(Ham’s cherry picked quote again in bold red):

The Limitations of Science
Science is powerful, but limited in the kinds of questions it can help answer. Science requires repeatable observations and testable hypotheses. These standards restrict science to a search for natural causes for natural phenomena. For example, science can neither prove nor disprove that unobservable or supernatural forces cause storms, rainbows, illnesses, or cures of disease. Supernatural explanations of natural events are simply outside the bounds of science. There is no way to show that such hypotheses are false.

Although science is “a way of knowing,” keep in mind that it is not the only way. Not everything you “know” is based on science. For example, you know what kind of music you like and what your favorite color is. These personal tastes are not the results of a careful testing of hypotheses. And you know right from wrong. This concept is an ethical value, not a scientific fact. Each human mind develops a unique database of knowledge of many different kinds. Science-based knowledge is the type built from confirmed observations and testable hypotheses.

Theories in Science
Many people think of science mainly as a collection of facts. But collecting facts is not what really defines science. A telephone book is an impressive catalog of factual information, yet it has little to do with science. It is true that factual data provide the raw material for science. But scientists are mostly interested in finding patterns in the data and explaining these patterns. What really advances science is some new theory that ties together a variety of facts that previously seemed unrelated. People like Isaac Newton, Charles Darwin, and Albert Einstein stand out in the history of science because their theories connected so many observations and experimental results.

How is a theory different from a hypothesis? In science, a theory is a well-tested explanation that makes sense of a great variety of scientific observations. It gives rise to many hypotheses that can be tested. This definition contrasts with the everyday use of theory to mean a speculation, as in “It’s only a theory.” Compared to a hypothesis, a theory is much broader in scope. This is a hypothesis: “Mimicking poisonous snakes is an adaptation that protects nonpoisonous snakes from predators.” But this is a theory: “Adaptations such as mimicry evolve by natural selection.” The theory of natural selection explains the evolution of the many cases of mimicry, as well as a variety of other adaptations of organisms to their environments.

Theories, such as the theory of natural selection, only become widely accepted in science when they are supported by an extensive body of evidence. That evidence also provides a framework for further research and predictions. If new evidence that contradicts a theory is uncovered, scientists first verify the evidence many times. They then modify or discard the theory accordingly.

Of course Ken left out all of this which explains why scientific explanations exclude supernatural explanations (their lack of testability) and how scientific theories, like evolution are “well-tested”. This isn’t dogmatic atheistic limitation on science, as Ken would have his readers believe, rather testability is a practical limitation of science because it is the only way to demark fanciful speculations and religious myths from potentially valid explanations.

But Ken and other creationists can’t have this because their particular theology demands a particular interpretation of their scripture that is incomputable with not only evolutionary biology but with the findings of much of the rest of science (which they falsely label as “evolutionist science” or similar). For YEC, whose beliefs require the Earth and universe to be young (6000 to 10,000 years old), whenever they posit a testable hypothesis, such as the fossil record being explainable as the actions of a single event, in this case the Noachian Flood described in the book of Genesis, these hypotheses have been falsified. In the case of Flood geology in innumerable ways, something known to late 18th and early 19th century creationist geologists long before evolutionary theory was accepted.

This, by the way, is what led to the development of so called “Intelligent Design theory” (ID). ID creationists wanted to rid themselves of having to defend already falsified hypotheses, and of making direct references to Genesis, so as to avoid both scientific and First Amendment objections to their ideas being taught in public school science classrooms.  

Once Flood geology and a few other potentially testable creationist hypotheses have been ruled out by science (or deliberately left out by ID proponents) all they have is “God did it” (or the “Intelligent Designer did it”) which is not testable against the empirical evidence. An omnipotent creator could create anything, in any way, making any possible observation of the facts potentially compatible with God having done it.

So, anyway, more evidence (as if it were needed) that Ken Ham is not an honest interlocutor.  

Mendacious creationists won’t fess up

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First some context. Back in 2012 I wrote an article on yet another benighted creationist attack on 19th century zoologist Ernst Haeckel, written by The Institute for Creation Research’s (hereafter ICR) Dr. Brian Thomas, (Thomas 2012) implying that Haeckel—and some comparative embryology plates from the 3rd edition of his book The Evolution of Man (1874)—are responsible for the idea that the embryos of tetrapods (terrestrial vertebrates) at one point in their development posses structures often commonly referred to as “gill slits”, more properly pharyngeal clefts and pouches.

This is of course utter nonsense, as I have written on this extensively in other posts (see related links below); however embryological pharyngeal structures are not the real point here. Rather it is a quote, or I should say misquote, cited by Thomas, from a textbook, Biology (2007), authored by Sylvia Mader and a “correction” ICR has made in an editor’s note since added to his article.

In his article Thomas uses the “quote” in question—and Mader’s use of comparative embryo illustrations based, at least in part, on Haeckel’s—to imply that Mader is A) unjustifiably interpreting embryological evidence as being supportive of evolutionary theory, and B) That she isn’t up to date on the true state of comparative vertebrate embryology and Haeckel’s “discredited” illustrations.

First Thomas’s mangled quote of Mader:

Thomas: Mader wrote:

At some time during development all vertebrates have a postanal tail [spinal cord-like scaffold] and exhibit paired pharyngeal pouches… In humans, the first pair of pouches becomes the tonsils, while the third and fourth pairs become the thymus and parathyroid glands. Why should terrestrial vertebrates develop and then modify such structures like pharyngeal pouches that have lost their original function? The most likely explanation is that fishes are ancestral to other vertebrate groups.3

But how does Mader know that the pouches “lost original function?” She doesn’t—she makes the statement on the basis of evolutionary belief, not on scientific observation. She even lists the pouches’ critical functions for human development. Since the pouches are tissues organized into folds and have known functions, then there is no scientific reason to even suspect that they reflect any evolutionary past.3

Now Mader’s quote with some context and significant parts mysteriously missing or altered from Thomas’s version (the parts of significance missing/altered in Thomas’ version in boldface):

The homology shared by vertebrates extends to their embryological development (Fig. 17.16). At some time during development, all vertebrates have a postanal tail and exhibit paired pharyngeal pouches. In fishes and amphibian larvae, these pouches develop into functioning gills. In humans, the first pair of pouches becomes the cavity of the middle ear and the auditory tube. The second pair becomes the tonsils, while the third and fourth pairs become the thymus and parathy­roid glands. Why should terrestrial vertebrates develop and then modify structures like pharyngeal pouches that have lost their original function? The most likely explanation is that fishes are ancestral to other vertebrate groups. (Mader 2007, p. 296)

As I noted in my previous post on Thomas’s article, he replaces Mader’s reference to the fact that the pharyngeal apparatus of vertebrate embryos develop into functioning gills in not only fish but also the larva of amphibians as well, with three little dots (beware creationists bearing ellipses…!). I think it is fair to speculate that Thomas does this due to the fact that these functioning gills in amphibians inconveniently bridges a gap between gilled fish and fully terrestrial, air breathing, vertebrates; something he would rather not have his readers contemplate.

This omission, as we will see, is not mentioned in the more recently added editor’s note.

In the second boldfaced part of the correct Mader quote we see that Thomas somehow altered the quote to make Mader wrongly say that the first pair of pharyngeal pouches are modified during development to become tonsils, rather than the middle ear and auditory tube (eustachian tube). On the other hand it is in fact the second pharyngeal pouches that gets modified into the tonsils.

All this has been merely the backdrop for the quote from Mader’s Biology (2007), Thomas’s mangling of said quote and ICR’s “correction” of Thomas’s mangle. Somehow in the intervening year since I pointed out the problems with Thomas quote or Mader—and I don’t know if it was my pointing it out that caused it—an editor of the ICR’s website became aware of Dr. Thomas’s little oopsie on which pharyngeal pouch becomes what, and decided to add a face saving note correcting the error, however the devil is in the details of this “correction”:

Editor’s note: Updated embryology specifies that the first pair of embryo pouches develops into the middle ear, not the tonsils as the above Mader quote states. “The first pair of pharyngeal pouches become the auditory cavities of the middle ear and the associated eustachian tubes. The second pair of pouches gives rise to the walls of the tonsils.” (Gilbert, S. 2014. Developmental Biology, 10th ed. Sunderland, MA: Sinauer Associates, Inc., 478.)5

Here we learn that “Updated embryology” has created a need to correct misinformation stated in the “Mader quote” on the developmental destiny of the first pharyngeal pouches. That would be the quote where Mader provided accurate information in her textbook which was then mangled by Thomas while conveying it to his audience.

It’s not Thomas’s fault you see, it is because Mader needed to be “updated”.

How contemptible do you have to be to first butcher a quote from a scholar and then when your malfeasance is pointed out to imply that it is the scholar’s information that is at issue rather than your honesty and/or competency?

Update: Having gone back and looked at Thomas’s article I realized that despite the editor’s note correcting the misinformation about the first pharyngeal pouch (arch?), the misquote of Mader has not been corrected. This leads me to speculate that they (whomever at ICR added the note) haven’t actually figured out that Thomas screwed up the quote.

Top notch stuff.

Related Links

“Creationist foists “fraudulent” embryo picture on his readers” (2012) by Troy Britain

“Gill slits” by any other name…” (2012) by Troy Britain

“Responding to a comment on my article: “Gill slits” by any other name…” (2016) by Troy Britain

“Haeckel’s ABC of evolution and development” (2002) by Michael Richardson & Gerhard Keuck

“Ernst haeckel’s ontogenetic recapitulation: irritation and incentive from 1866 to our time” (2002) by Klaus Sander

“Pictures of Evolution and Charges of Fraud Ernst Haeckel’s Embryological Illustrations” (2006) by Nick Hopwood

“Accuracy in embryo illustrations” (2008) by the National Center for Science Education

“Haeckel’s embryos: fraud not proven” (2009) by Robert J. Richards

References

Haeckel, Ernst (1874) The Evolution of Man

Mader, Sylvia S. (2007) Biology (9th ed.), McGraw-Hill

Thomas, Brian (2012) Do People Have ‘Gill Slits’ in the Womb?, ICR website accessed on 3-17-2024

Discussing Natural Selection

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I was invited to participate in a livestream discussion about natural selection. In this case it was for The Crucible livestream on the Promethean Secular Frontier Network on YouTube. This episode of The Crucible was hosted by Sunny Shell and my fellow panelists were Aron Ra, the prolific YouTube defender of evolution, and Brit Garner, science educator and host of the Nature League YouTube channel. I had a lot of fun doing it, hopefully I will get a chance to do more of this new fangled moving pictures technology. My thanks to Sunny and Wes (the producer) for having me on and to Phil Calderone for suggesting me to them (Phil invited me a few years ago to join him in a debate against a couple of creationists).

Give it a watch:

So I was on a panel discussion about micro vs. macroevolution…

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Several weeks back I get an email from Phil Calderone, a member of one of the local atheist/agnostic/freethought groups (I.E.A.A.), asking if I would like to act as a fill in on a (then) upcoming “believers vs. non-believers” panel discussion on the subject of micro vs. macroevolution. Apparently, one of the persons originally invited was not going to be able to participate and he needed a fill in and was pointed towards me by Dr. Brad Hughes, who many years ago I had helped (along with others) prepare for a debate with “Dr.” Kent Hovind.

After some trepidation—due to having never done any public speaking before—I agreed to participate as long as it was understood that I was unlettered and neither a paleontologist or biologist but rather a mere amateur naturalist who has had a bit of experience in the creation/evolution debate. 

The format of the discussion was meant to be a relatively informal back and forth between four people with two on each side. One the “believers” side there was a gentleman named Kelly Clemensen, of something called the Areopagus Project, and Dr. Paul Giem of Loma Linda University (see also Giem’s web page here). On the non-believers side was myself and Phil Calderone who was to moderate but had to fill in the second non-believers chair for another person who couldn’t make it.

I will not go into any more description of the event as it was recorded on video and you can watch the proceedings for yourself below. However, truth and honesty before all I will be addressing at least two places where I know I screwed up in the discussion below the video.

Please feel free to point out any other mistakes I made, or address the many points made by the creationists that went unaddressed by either Phil or me during the discussion. I know there are whole bunches of things that our opponents said that was missed or deserved more in depth dissection.

Now that you have, hopefully, watched the video there are two places that I realized I messed up pretty much right after the debate. One was minor memory failure, misattribution about punctuated equilibrium. The other was a more significant—at least in my opinion—point were I brought up a group of fossil organisms that was really something of a red-herring—though I committed the fallacy out of partial ignorance—and should have known better from other statements I myself had made at other points in the same discussion!

Read on»

Is “The Imminent Demise of Evolution” still imminent?

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Ten years ago, in 2006, intelligent design creationist William Dembski predicted that in a decade evolution would be toast:

LOUISVILLE, Ky. (AP) – To William Dembski, all the debate in this country over evolution won’t matter in a decade.

By then, he says, the theory of evolution put forth by Charles Darwin 150 years ago will be “dead.”

Yeah, well…

Meanwhile I stumbled upon this today (dated 11-17-2016) from young Earth creationist Richard William Nelson:

Despite a flood of challenges since the publication of The Origin of Species in 1859 by Charles Darwin and more than 150 years of unprecedented scientific efforts in the history of mankind to prove otherwise, the evidence examined in nature tooled with unprecedented technology continues to be compatible with the Genesis record written by Moses…

…Evolution, once a theory in crisis, is now in crisis without even a cohesive unifying theory.

Biological evolution exists only as a philosophy, not a science.

For a long list of creationists predicting the death of evolution see this following:

The Imminent Demise of Evolution: The Longest Running Falsehood in Creationism by Glen Morton

Jack Chick is dead…

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image_1477796812_44571917I can’t believe I hadn’t heard about this already but apparently the infamous Jack Chick, author of those vile little sooo bad they’re almost good cartoon religious tacts that you would sometimes find stucked under a windshield wiper on your car, or laying in a parking lot after someone pulled it out from under their windshield wiper and threw it on the ground… Yeah those, died last Sunday (10-23-2016) at the age of 92.

There were so many “great” tracts, like Dark Dungeons that attacked the game Dungeons and Dragons and in which Chick claimed that D&D could lead you to practicing actual, for reals, black magic.

0046_05

But of course for me the pièce de résistance was his antievolution tract, Big Daddy, wherein we read the story of an intrepid young creationist student who schools his teacher on how foolish and wrong evolution is, concluding with the teacher leaving head hung low in disgrace. Hilarious!prof-quits

Ah well, bye Jack, Big Daddy will always hold a special place in my… in my… ah, well, bye Jack and my condolences to his loved ones.

Responding to a comment on my article: “Gill slits” by any other name…

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I have decided to move this up from the comments section (cuz why not?) of my article “Gill slits by any other name…

Andy: Hi Troy, I read your post, and it is very well argued.

Thanks. [He said knowing that a “but” was coming.]

Andy: At the moment, I am a biology student at a local university, and one of my personal headaches is the promotion of either creation-ism or evolution-ism. To be honest with you and with all due respect, I really don’t care for either explanation.

Andy, with all due respect, you should know that for someone like me who has been in the “trenches” debating people pushing pseudoscience for years, the fact that you would refer to evolutionary theory as “evolutionism” is a large red flag that would strongly lead me to suspect that your understanding of evolutionary theory and science itself is likely wanting.

Unfortunately, your next sentence does little to disabuse me of my suspicion. Creationism is set of theological beliefs regarding a creation story written down in the 6th or 5th century B.C.E., accepted on faith and in the face of contravening facts by a tiny minority of people with any scientific background. Its mechanisms (God did it) are untestable and to the extent that it makes claims testable against the empirical world it has been falsified a thousand times over.

On the other hand evolutionary theory is a scientific explanation for a vast number of facts that is testable against further observations of the empirical world and used by the vast majority of the relevant scientific community as a guide to further research…whether you “care” for it or not.

That you would casually place them on the same level is yet another huge red flag.

Andy: As a student, the only thing that I am concerned about is true scientific facts that have been tested at a laboratory to the molecular level.

We are only three sentences in and we have three red flags. In my experience people who use terms such as “true scientific facts” (as opposed to what, “false scientific facts”?) tend to not to be particularly familiar with either the facts or what counts as scientific.

However, that is a nit compared to the philosophical problems with your above statement. Why on Earth would you limit yourself to what is testable in a laboratory at a molecular level? Better yet, why should anyone else take your narrow limits as to what to be concerned with seriously? Using your bizarre limitations, we would be throwing out vast swaths of empirical data, and not just in biology.

Molecules are great but they are not a perfect path to knowledge nor are they the only path.

Furthermore, the point of science is not simply collecting random facts, rather it is about explaining the facts that we observe [insert Darwin quote about collecting pebbles here]. In this case, we have detailed anatomical, physiological and genetic similarities between the pharyngeal structures of terrestrial vertebrate (hereafter “amniotes“) embryos and non-amniote vertebrates (amphibians and “fish”), set against a particular paleontological backdrop that needs a coherent explanation.

You do not like creationism, great. That should be a given and I am with you. However if you do not like evolutionary theory, then what is your better explanation for the gill-like appearance of the pharyngeal structures of amniote embryos (and everything else evolution explains)?

You cannot just sit back and say, “I don’t buy any of it” and expect to be taken seriously, especially in face of the apparent success of evolutionary theory.

Andy: My teacher presented this same example about the gill slits during a microbial genetics lecture.

I am not sure how the “gill slits” of vertebrate embryos are relevant to the genetics of microbes but OK…

Andy: I was just exhausted of listening, so, I raised my hand and said that the information was outdated and more up-to-date data has been collected explaining that they are no longer gill slits, and they are pharyngeal pouches.

Huh, did you read my article to which you are supposedly responding? You are literally arguing semantics here. Regardless of what we call these structures in the embryos of amniotes, they exist, they resemble—in detail—the developing gills of non-terrestrial vertebrates, and we want to understand why this would be so.

Andy: He asked what was my source, and my reply was, with all due respect, professor, but your source is 150 years old and newer information was out that did not concentrate on a belief based teaching. He stopped and said he will do some more research and get back to us. He continued with the lecture as it was intended.

I am sorry but “your source is 150 years old”, even if true, is not an argument; old ≠ incorrect. FA = -FB (for every action there is an equal and opposite reaction) gets robotic probes to Mars despite the fact that Newton came up with the formula over three hundred years ago.

Furthermore, what is this “belief based teaching” to which you refer? Once again, if you read my article you would know that referring to these structures as “gill-slits” is not dependant on a belief in either creation or evolution as is evidenced by the fact that pre-Darwin creationists called them this.

Oh, and what is your source Andy?

Andy: I agree; they look like gills until you dissect it, and then they look like pouches. I know in biology we name a lot of things base on morphological characteristics, and that is a great easy way to remember things.

No, no, no, again did you even read my article? Here, look at this diagram again:

Source bionalogy.com, with modifications.

Source bionalogy.com, with modifications.

There are clefts (or grooves) on the outside of the pharynx (red arrows) with corresponding pouches on the inside (blue arrows). These clefts and pouches are each separated by membranes that, in mammals, normally remain unperforated with the first (tympanic) membrane forming the so-called eardrum. Some of the post tympanic membranes do normally perforate and then reclose in some birds and reptiles embryos. They also temporarily perforate in the gill-bearing larvae of some amphibians and, of course, in fish they stay perforated and become gills.

Since I know some people are queasy about diagrams here are a few photographs of coronal sections done on various mammal embryos. First, an electron microscope picture of what I think is a stage 13 human embryo (Etchevers, 2008)(blue arrow points to the pharyngeal pouch and red to the corresponding cleft).

(Etchevers, 2008)

For comparison, here are some stained sections from a mouse (left, Zhang et al. 2005) and a pig (right, Shone & Graham 2014) at a similar point of development; once again blue arrows for pouches and red for clefts. Also, note in these photos that the aortic arches—the blood vessels—are visible within the pharyngeal arches (green arrows).

(Left, Zhang et al. 2005 – right, Shone & Graham 2014)

These are not just “pouches”! There are arteries (the blood vessels shown above), muscles, nerves and cartilaginous structures found on either side of the cleft/pouch pairs in the embryonic gills of “fish” and the corresponding pharyngeal arches of amniote embryos.

How do you get from this to, “they look like gills until you dissect it, and then they look like pouches” without ignoring all of these observable facts? These things exist and you need to explain them Andy.

Andy: The only thing that really gets to me is that either creationist or evolutionist keeps trying to push the subject in school.

The reason a competent science teacher (i.e. one who teaches evolutionary theory) would bring them up is because they are structures that have interested biologists since they were first discovered and whose existence is elegantly explained by descent from a common ancestor (evolution).

Andy: Honestly, I paid for one of my books close to $300. I feel that my book should be filled with up-to-date information that has been tested, and that is going to help me in the future and not filled with propaganda of any kind.

The pharyngeal structures of amniote embryos are not propaganda. They exist and are observable by anyone with eyes to see. For example, please note that the photographs of the pharyngeal sections of mouse and pig embryos I reproduced above were both taken from papers published within the twenty-first century. Any modern textbook on vertebrate developmental biology is likely to have similar photos or diagrams of these structures.

Andy: I guess it is easier to print the old stuff than to update the books to what they are intended to do, and that is to provide useful information that can help us treat diseases and give our patients a fighting chance.

Sorry Andy regardless of whether it comes from an older source or a current one, pharyngeal clefts, or “gill slits” exist in amniote embryos whether or not you want to accept the facts or the current best explanation for them, so please spare us the overwrought “won’t someone think of the ill people?!” shtick.

Andy: To this day, I haven’t seen a mermaid or an angel either in nature or in a lab, so, I will have to dismiss both claims as pending research and proper laboratory testing.

53435573

Yeah so at this point, I am starting to have doubts that you are for real Andy and not just a troll looking for attention. What the hell does a mermaid have to do with anything Andy? Please tell me you are not seriously suggesting that evolutionary theory somehow supports the existence of mermaids [Hint: the exact opposite is the case]. Because if you think it does, you may want to rethink your career path—perhaps something in the arts?

Andy: Please don’t take this the wrong way. I am a paying student who is discordant with the never-ending stories.

As I said, after the mermaid comment I am no longer sure how to take you Andy. Perhaps your response or lack thereof will clarify that question.

Regardless I want to thank you Andy. Formulating my response to you has made me consider adding a few things to my “gill-slit” article that I think could use some expansion or clarification. So anyway, Poe, troll or sincere, something positive has come from your comment, thanks.

References

Etchevers, Heather (2008) Development of the branchial arches (slide presentation downloaded on 10-29-16)

Shone, Victoria & Graham, Anthony (2014) Endodermal/ectodermal interfaces during pharyngeal segmentation in vertebrates, Journal of Anatomy, 225(5):479-91

Zhang, Zhen et al. (2005) Tbx1 expression in pharyngeal epithelia is necessary for pharyngeal arch artery development, Development, 132:5307-5315

Playing Chess with Pigeons on Facebook

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While I have had a link to my personal Facebook page in the sidebar for some time, I don’t know if I have ever mentioned here that Playing Chess with Pigeons has its own Facebook page… Well, now I have.

I generally post cartoons and news stories directly related to CvE as well as links to science news stories that I think are interesting and/or obliquely related to the CvE debate.

Anyway, have a look, like, subscribe, share…

Consilience and whale evolution

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Way, waaay back in December of 2005 (ye gods has been ten years already?!) I wrote a Feedback response on the Talk Origins Archive to a question about the vestigial pelvic bones found in modern whales. In this case the questioner did not believe them to be truly vestigial, no doubt due to holding erroneous beliefs regarding the subject. In my response I of course took the time to correct their faulty views, however I also used the opportunity to talk about the concept of consilience wherein multiple independent lines of evidence converge on a single explanation, giving us greatly increased confidence that those explanations (hypothesis/theories) are likely to be accurate reflections of reality, i.e. “true”. 

I have now and again thought of going back and using that post as a spring-board for a more detailed examination of this subject and who knows, I may still do so someday. In the meantime however, here is a great video from Stated Clearly that I ran across on Facebook recently that uses the same topic—whales—to essentially do the same thing I did all those years ago; make a point about the consilience of evidence pointing to a pretty definite conclusion with regards to not just the ancestry of cetaceans but the evolution of life in general. Better they include more details than I did and it has animations.

Check it out:

I miss answering the feedback question on Talk Origins…