Monday, August 29, 2016

Why do lizards have blue tails?

I found this little guy hanging on the wall outside my office the other day, and he obliged me with one photo (but then got skittish and ran away).  This is Plestiodon fasciatus,  the five-lined skink, which is extremely common in the eastern U.S.  We have several that live on our porch.  I see them at least once a week.

My lizard friend reminded me of a fantastic study I heard about years ago at an Evolution conference.  The paper was published by Watson et al. in Zoology in 2012.

The basic question is, Why do lizards have blue tails?  One reason animals develop strange colors is for mating.  Another possibility is that they might give  the animal some kind of protection.  The protection idea is especially interesting, since these lizards can blow their tails when attacked.  It's called autotomy, and the tail wiggles around after it detaches.  This wiggly tail presumably gives predators a decoy to distract them while the tail-less lizard gets away.  But why would a tail be blue?

To investigate this, Watson et al. created little clay models of lizards.  They made lizards that were all black, black lizards with blue heads, black lizards with blue bodies, and black lizards with blue tails.  The researchers then put their lizard models along river banks in Texas on twigs and logs where lizards would normally hang out.  The study site also had real lizards and the birds that normally prey on the lizards.

After 48 hours, they inspected their models to see what happened.  Bird attacks would register as claw marks left in the clay.  They found that regardless of the model, the average number of bird attacks was the same, which means that the blue color didn't make the lizard more likely to be attacked by a bird.  There was a significant difference in where the birds attacked, though.  Blue heads had significantly more bird attacks than bodies, and blue tails also had significantly more attacks than bodies.

So it seems like the blue color of the tail attracts bird predators that would already attack anyway.  They see the blue color and go for that instead of the lizard's body.  Since lizards can survive an attack on their tails but not on their bodies, having a blue tail is a great way to avoid death by bird predators.

Ain't creation grand?

Watson et al. 2012. The fitness consequences of the autotomous blue tail in lizards: an empirical test of predator response using clay models.  Zoology 115:339-344.

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Monday, August 22, 2016

I finished another book

Some of you know that I've been writing a textbook over the past year.  It's called Introduction to Science, and it's intended to explain the basic operation of science to high school students.  So I've tried to write very simply, which has been quite a challenge for me (as you might guess).  I keep discovering that my vocabulary has matured considerably since I was in ninth grade.  Go figure.

Anyway, Core Academy just finished printing up a small run of the book for use in two high schools this school year.  I'll use their feedback for more revisions.  Check out the press release from Core Academy, and then visit the Introduction to Science website for a sample chapter.

And now I must begin my class for the morning...  Have a great day!

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Wednesday, August 17, 2016

The Core Academy library is still going strong

When Core Academy launched in 2013, I wasn't sure what to do with the old CORE library.  I knew we had something important in the library.  It was a valuable resource, and it is one of the few such libraries that is publicly accessible.  But I wasn't sure the new Core Academy would be able to support it and keep it growing.

I was very wrong about that.  The library grown substantially in the past three years, both in overall size of the collection and with important new items added. A few of the new things we've acquired:

  • John Reid's scrapbook on the alleged "Triassic shoe" fossil
  • An original English printing of Thomas Burnett's 1684 Sacred Theory of the Earth
  • A first edition of Inherit the Wind signed by playwrights Lawrence and Lee
  • More than thirty original photographs of the Scopes Trial
  • Books and notes originally owned by creationist pioneer Byron C. Nelson
We've also added so many books to the collection that we're literally overflowing our space.  We've never had quite enough room for the library, and we've had to split it up in different rooms for the past ten years.  As Core Academy has grown, the library has become cluttered and hard to use.  Recently, the Lord answered our prayers and made some affordable new space available to us.  At last, we have enough room for the entire library to be relocated to a single location!  You can see our new location in the photo above (we just started moving the journal collection).

You might be wondering exactly what the big deal is.  After all, why would a startup nonprofit bother with the expense of a library?  The reality is that all good research begins at the library.  Every scholar builds on the foundation of scholars that came before.  As we at Core Academy seek to build a better way of understanding science and faith, we rely on the work of hundreds of scholars found in our library.  There we can find out what ancient Christians thought about Cain's wife or just when flood geology really began.  The library is our great cloud of witnesses that cheers us on as we run the race of faith.

Cleaning up and moving a library as big as ours is no small task, though, and we could use some help.  If you are local to Dayton or the surrounding area and you would like to volunteer some time to help us with moving, cataloging, labeling, and shelving our library, please send me an email.  We'll add you to our mailing list of volunteers.  Now that school has started, we'll have a lot more time every week for local work like this, and we could really use the help.  I also want to say thank you to everyone who already helped with this project or who donated money or items to the library.  You are a huge blessing to us and to the future generations of faithful Christian science students that we minister to.

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Monday, August 15, 2016

The Piltdown forgery

A reconstruction of Piltdown
Man, Wikimedia
Headlines all over the world are trumpeting the notion that the Piltdown mystery has finally been solved.  They are all referencing a new study of the Piltdown remains published by De Groote et al. in Royal Society Open Science, in which the authors conduct some new analyses of the most famous fake fossil in the history of science.  Once again, contrary to the hype, they did not solve the mystery.  If you actually read the paper, their conclusion is that one suspect is just "most likely."

In case you're unfamiliar with the strange history of Piltdown Man, here's the story: In 1912, a man named Charles Dawson informed the Natural History Museum in London that he'd found some fossils and stone tools.  The fossils consisted of some skull fragments and a jaw, all of which appeared to be quite old.  The keeper of geology at the NHM, Arthur Smith Woodward, named it Eoanthropus dawsoni "Dawson's dawn man."  For a time, it was a pretty sensational discovery, but its importance was later eclipsed by discoveries in Asia and Africa.  It wasn't until the 1950s that Piltdown man was shown to be a hoax: the jaw of an ape and the skull of a human, all filed and stained to look very old.  The question is: Who is the culprit?

Prior to this study, most of the evidence favored Dawson.  He was the one who first brought these fossils to the public's attention, and he was the only one who had access to a supposed second site, from which he produced additional "fossils" before his death.  He had wanted for years to be recognized for his discoveries in antiquities and maybe even become a Fellow of the Royal Society.  In my estimation, the smoking gun was revealed earlier in this century, when a study of other "antiquities" discovered by Dawson uncovered dozens of other forgeries.  Piltdown was apparently just a crowning achievement on a lifetime of faking and forging antiquities.

So what does this new study add to our knowledge?  New CAT scans of the remains indicate a common modification methodology to all of the Piltdown man discoveries, indicating that they were all very likely the product of a single craftsman.  DNA and morphometric analysis of the jawbone and teeth indicate that they probably came from a single orangutan.  And that's it.  These new findings rule out some of the other suspects, but the overwhelming evidence of Dawson's guilt isn't enhanced very much by these discoveries.  This is reflected by De Groote et al.'s conclusion, where they call Dawson the "most likely" suspect:
The consistency in the MO observed in the specimens, and the use of a limited number of specimens to create both the Piltdown I and Piltdown II material, are indicative of a single forger. This was most likely Charles Dawson—the prime suspect since the fraud was exposed in 1953.
What does the Piltdown story mean for us today?  Honestly, I'm not sure it means all that much.  Some creationists are obsessed with it, but it isn't really all that important.  It's been more than sixty years since it was exposed, and there are hundreds of far more important and legitimate hominin fossils now known.  I guess if there's a lesson to be learned, it might be something like this: Scientists are human, and they can make mistakes just like anyone else.  Even when they make mistakes, though, it is through more scientific study that we can discover those mistakes.  We creationists ought to take note: If we think the evidence for evolution or the ancient earth has been mistakenly interpreted by modern science, then it behooves us to do the scientific research needed to provide some other explanation for that huge body of evidence.

Hey!  I guess that's an important lesson after all.

The article is open access, so you can read the whole thing for free right here:

De Groote et al. 2016. New genetic and morphological evidence suggests a single hoaxer created ‘Piltdown man.’  Royal Society Open Science 3:160328.

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.

Monday, August 8, 2016

Darrow statue is not another raging debate

Yesterday, the Chattanooga Times Free Press published a piece on the effort to erect a statue of Scopes trial defense attorney Clarence Darrow on the courthouse lawn in Dayton, TN, where I live.  The headline is In 'Scopes Monkey Trial' Home, an Evolution Debate Rages on.  When I first read that headline, I thought, "Oh no, what did I miss?"  Then I realized that it was the article on the Darrow statue that I'd already heard about.  So what is this debate that "rages on?"

Let me set some context here.  In 2005, Bryan College celebrated its 75th anniversary, and part of that celebration was the commissioning of a statue of their namesake William Jennings Bryan.  The statue was sculpted by Chattanooga artist Cessna Decosimo, and as far as I know, it was paid for by the college.  The county agreed to allow it to be erected on the courthouse lawn.  Even at the time, I remember mutterings about, "What happens if someone wants to erect a statue of Darrow?"  The answer I heard then was, "We let them."

Ten years later, a group calling itself the Committee to Honor Clarence Darrow finally decided to do just that.  The new statue is being designed by Zenos Frudakis, and the Committee is trying to raise the necessary money to put it on the courthouse lawn across from the Bryan statue.  Who is this committee?  Inaugural members come from the American Humanist Association, the Freedom from Religion Foundation, the Americans United for the Separation of Church and State, and the Freethought Society.  So not exactly folks I agree with.

Our local Rhea County Historical and Genealogical Society first considered the request to erect the statue in early 2015, and Society president Tom Davis said that in the interest of fairness and recognition of what happened at the trial, we should let them put up the statue.  After all, it was the conflict between Darrow and Bryan, two outspoken and passionate advocates of very different positions, that brought such notoriety to the trial.  It makes sense to honor both of them.

That attitude is the same that you'll find in the Scopes Trial Museum at the courthouse.  I remember my first time visiting the museum (years ago) and how impressed I was at the fairness with which Darrow was treated.  There's a huge display panel about him just like there's a huge display panel about Bryan.  Both of their positions are given reasonable and honest treatment.

In fact, fair and reasonable treatment has been a recurring theme over the years as I've interacted with various folks on the "other side" of the evolution debate when they talk about their time in Dayton.  Just a few weeks ago, Randy Moore and Susan Epperson were both here at the Scopes Trial Play and Festival, and they apparently had a great time.  From the things he's said, I take it that Randy is very fond of this town (he visits often), even though he's a firm opponent of creationism.

With all that in mind, what kind of debate is now raging, according to the Chattanooga Times Free Press?  I'm not sure.  The article almost undercuts its own headline.  Local newspaper editor Reed Johnson put the Darrow statue on the front page back in February:

But apparently that hasn't stirred up much fuss, according to the Times Free Press:
One might expect a town that reveres Bryan to resist efforts to memorialize his antagonist, but Reed Johnson, managing editor of The Herald-News in Dayton, said that vocal resistance hasn't materialized. He doesn't recall angry letters to the editor.
But wait!  There's at least a seed of potential controversy:
County Commissioner Bill Hollin said he doesn't think many people are aware of the effort, but he's against it and thinks others will join him.
OK, there you go.  What does Historical Society president Tom Davis think about this?  Same thing he said in the local article from February (and the same thing he told me in 2005):  If we accept a statue of Bryan, we'll have to accept a statue of Darrow some day to be fair.

What a raging debate!  Remember everyone: Headlines are designed to get you to read the article.  This one is almost comical in how much different the headline is from the reality that the article itself describes.

So what do I think?  Honestly, I think it's a great idea.  Here's another quote from Tom Davis that the Times Free Press didn't pick up (it's from the Herald-News article):
We don't want to stir up controversy or continue the battle from the 1920s, but rather just recognize it as a major part of our history.  I think it will be a unique feature for Dayton and a good idea to have both [Darrow] and Bryan represented.  We're not advocating a position.  We are simply trying to accurately tell the story.
Well said, sir.  Darrow was just as important to history as Bryan.  When he arrived in Dayton for the trial in 1925, he was met with a crowd at the train station and treated to a special banquet just like Bryan.  That is the Dayton I know: welcoming even to people on the other side of ideological divides.  We welcomed Darrow then, and we can welcome him now.

Feedback? Email me at toddcharleswood [at] gmail [dot] com. If you enjoyed this article, please consider a contribution to Core Academy of Science. Thank you.