Of Pandas and Pigeons

I have had the honor of being invited to join the crew over at Panda’s Thumb, the premier counter creationism blog on the interwebs and have gladly accepted.

Your truly with a Prof. Steve Steve impersonator.

Fear not my minions (all 5 or 6 of you), Playing Chess with Pigeons is not going anywhere! This is will remain the focus of my blogging. Little things here; big things here but cross posted to Panda’s Thumb as well (more traffic, more better!).

Thanks to the Panda’s people for having me, I hope to live up to the honor.

The Carnival of Evolution #50 is up!

That’s right the Carnival of Evolution has reached the big 50 and it’s rarin’ to go with The Teaching Edition!

So go with the flow and go, go, go on over to Marc Srour’s blog Teaching Biology!

The Carnival of Evolution, like a fine wine, gets better with age…

Previous Carnivals of Evolution:

If you missed any of these you’ll definitely want to go check them out!

The Carnival of Evolution #49 is up!

Another month has passed and another Carnival of Evolution(#49) has arrived for your edification. This month it is being hosted by Mousetrap: ecology & evolution footnotes and you NEED to go and absorb ALL the evolutionary knowledge it contains! Fly my minions, fly!!!

[OK, I don’t know where that came from… Maybe too much time spent around P.Z.. But it’s still a good idea!]

Previous Carnivals of Evolution:

If you missed any of these you’ll definitely want to go check them out!

“The silly things those creationists say” – Pharyngula podcast #2

I lucked out and was able to be one of the participants on biologist P.Z. Myers’ Pharyngula video podcast (#2). The subject of this podcast was, as you may have guessed by my post title, creationism. Russell Glasser of The Atheist Experience was also there, as were several other people who, while they were new to me, seemed to be hip to the subject. I really enjoyed it and the time just few by. 

My thanks to the other participants and especially to P.Z. for having me!

In which I yell at everyone on the interwebs

A Facebook friend posted a link to a YouTube video titled “Top Ten Creationist Arguments” by The Thinking Atheist. I had seen it before, it’s slickly produced and OK as far as it goes (though I would have a different list of 10 creationists arguments) but that’s not what got me going. In the video TTA gives a quote from the late Stephen Jay Gould:

This caught my eye because I have been researching stuff to do with philosophy of science, i.e. the testability of evolutionary theory and the difference between the so called experimental sciences and historical sciences. In particular I thought I had remembered reading a essay by Gould on the subject and I thought this quote might give me a lead on it. The problem is TTA doesn’t give a source for the quote. “No problem”, I thought, “I’ll just Google it and it should be a snap to find the source.” Bzzzt! Wrong. Oh if you Google the quote you’ll get a gillion links but none* of them give the source of the quote!

After a half and hour or so of Google mining I finally found a site that gave the source as Gould’s Dinosaur in a Haystack (1995), but it provided no page number! So I pulled my copy off the shelf, blew the dust off the top  (damn dust) and checked the index for references to creationism.

There were a couple and while Gould did say something like this in one part of the book referenced, it wasn’t an exact quote. Finally I went to Amazon.com and found that they allowed one to search the contents of the book, and at last I got the information I was looking for.

The quote appears on page 397 (of the 1st hardback edition) and is not one of the places listed in the index for the term creationism. Here it is with some context:

One tangential point before I leave this elegant study [a genetic study of certain crabs, see below – T.B.]. Creationists critics often charge that evolution cannot be tested, and therefore cannot be viewed as a properly scientific subject at all (see the next essay for a fuller discussion of this important issue). This claim is rhetorical nonsense. How could one ask for a better test, based on a very risky prediction, than this? The counterintuitive link between king and hermit crabs was postulated on the basis of classical evidence from morphology (the arguments detailed previously in this essay as points 1-3). This prediction was then tested by the completely independent data set of DNA sequence comparisons — and confirmed in spades, with even closer propinquity than suspected between king crab and hermit crab lines.

I regard this story of king and hermit crabs as one of the most elegant I have learned of late in evolutionary biology–a lovely combination of a fascinating and counterintuitive tale; a multifaceted, rigorous and convincing pile of supporting data; and a lesson of intriguing generality  (the difference between genealogical propinquity and any functional meaning of similarity–and the overriding importance of propinquity). (Gould 1995, p. 397, emphasis mine)

Great, curiosity satisfied!

So please, please, please, people, don’t just throw quote around willy-nilly. Give proper references. [I’ll make an exception for T-shirts, but that’s it!]

OK, I got that out of my system, end pedantic rant.

[* I didn’t look at every single Google result so this is a rhetorical “none”.]

Reference

Gould, Stephen Jay (1995) Dinosaur in a Haystack, Harmony Books, NY, 1st hardback edition

The Carnival of Evolution #48 is up and it has been Pharyngulated!

The Squidmiester himself, P-Zed Myers, who inscribes his electronic tome of iniquity (a blog) from atop a throne of humans skulls (a ordinary office chair), ensconced in his deep sea fortress of doom (the University of Minnesota Morris), is hosting the 48th Carnival of Evolution at his retched hive of scum and atheistic villainy, Pharyngula!!! You are not going to want to be late for this one, because the lucky ones will be eaten first!!!

Welcome your new Cephalopod overlord! I think he likes you…

Bwahahahahaha!!!

Praise be to Cthulhu for this invisible line break! Pain in the ass html…

Previous Carnivals of Evolution:

If you missed any of these you’ll definitely want to go check them out!

Call it, “blog security”

Gallup has issued the results of yet another poll on American’s views on evolution; human evolution to be specific (and that all most people care about). And the results are unfortunately in the same ballpark they’ve been in for decades. Roughly half (46%) of people in the U.S. believe that humans were created by God in the present form within the last 10,000 years.

The “good” news is that 32% of people polled accept that humans evolved over millions of years, but that God was involved in some way (though that is down from 38%!). To be sure that is not a scientifically defensible position but at least it isn’t an overtly science denying one. Combined with 15% who accept evolution, without adding any unscientific extras, that brings the total of evolution acceptors in the U.S. to 47%; which gives us a whopping 1% lead over the hard core creationists.

Hurray?

I guess it’s back to work then…

[Hat tip to Ed Brayton at Dispatches from the Culture Wars.]

“Gill slits” by any other name…

Charles Darwin once said that he thought the evidence from the comparative anatomy of embryos was “by far the strongest single class of facts” in favor of common descent (Darwin, 1860) and while it has since been eclipsed by genetics, it remains one of most compelling subsets of evidence for evolution. And perhaps the single most striking detail in the comparative embryology of vertebrates, are the structures colloquially known as “gill slits”.  

Embryonic “gill slits” or “branchial clefts” (branchia is Greek for gill) or more properly pharyngeal clefts (grooves, folds, etc.) are part of what is called the “pharyngeal apparatus” found in front (ventral) and sides (lateral) of the head/neck region of all vertebrates in the “pharyngula stage” of development. In “fish”, and the larva of amphibians, these develop into respiratory organs used to extract oxygen from water while in amniotes (“reptiles”, birds and mammals) they are modified into other structures.

Before I go on, a brief digression about “fish”. Throughout this article I will often use “fish” in the generic sense; but it should be noted that the term as it is commonly used—to refer to any vertebrate that swims in the water, has fins and gills—is not a valid scientific classification. This is because the three main types of animals commonly called “fish” —the Chondrichthyes (sharks, rays, skates and chimaeras), the Actinopterygii (ray fined fish, which constitutes the majority of living fishes), and the Sarcopterygii (lobe fined fish, the group from which four legged land animals, i.e. tetrapods, evolved)—are not a monophyletic group. That is they are not very closely related to each other despite some of their outward similarities (like gills). For example the living Sarcopterygii, lung fish and coelacanths share a more recent common ancestor with us (and all tetrapods) than with the other “fishes”.

OK, so the “pharyngeal apparatus” consists of a series of paired pharyngeal arches and fissures which develop on the exterior with a corresponding set of pharyngeal pouches on the inside of the throat, separated from the external fissures by a thin membrane (more on the details in a moment). And in fact the possession of these structures at some point in development, along with a hollow dorsal nerve cord, a notochord and a post anal tail, are the defining characteristics of the phylum chordata to which we and all other vertebrates belong.

Copyright © 1999 McGraw-Hill Companies, Inc.

Please note that the above illustration is diagrammatic and not intended to be photographically accurate (I have to say that lest I be accused by creationists of conveying a fraud). Below are actual photographs of both a skate embryo and a human embryo for comparison. Also note: the gill structures in the embryos of Elasmobranch fishes—the subdivision of Chondrichthyes which contains sharks, rays and skates—are much less derived than in other “fishes” and therefore generally more similar to those of amniote embryos than the corresponding structures in the bony “fishes” (which are significantly modified).

(Gillis et al 2009, p.5721)

The first of the arches, the mandibular arch, forms the jaw in all jawed vertebrates (Gnathostomes). Most vertebrates develop a total of six arches but the full complement is usually only retained into adulthood by hexanchiform sharks. Hexanchiformes are very plesiomorphic which means that they are more like earlier types of sharks.  Some species of hexanchiformes even develop a seventh arch. Likewise the extant jaw-less vertebrate, the lamprey, also have seven gill openings.

Read on»

leetle devil frog!

[Hat tip to Mom (she clips anything evolution related out of the paper for me).]

Extra! Extra! The Carnival of Evolution #47 is up!

Read all about it at Evolving Thoughts, blog of eccentric Australian philosophy mogul John Wilkins!


Previous Carnivals of Evolution:

If you missed any of these you’ll definitely want to go check them out!