Friday, January 08, 2010


Clueless in Seattle

The ever ridiculous Casey Luskin is over at the Discovery Institute's Ministry of Misinformation playing a variation on the ol' "if human beings evolved from monkeys, why are there still monkeys?" gambit. Yes, he really is that clueless ... or hopes his target audience is.

The occasion is the discovery of what appear* to be fossil footprints of true tetrapods that date to as much as 20 million years before Tiktaalik, our best example to date of a transitional form between fish and land animals. Naturally, Luskin is now crying: "Tiktaalik is not a transitional fossil!"

PZ Myers puts it in perspective:
[T]he mix of existing fossils tells us that there were viable, long-lasting niches for a diversity of fish, fishapods, and tetrapods that temporally coexisted for a long period of time; the evolution of these animals was not about a constant linear churn, replacing the old model with the new model every year. Comparing them to cars, it's like there was a prolonged window of time in which horse-drawn buggies, Stanley Steamers, Model Ts, Studebakers, Ford Mustangs, and the Honda Civic were all being manufactured simultaneously and were all competitive with each other in specific markets…and that window lasted for 50 million years. Paleontologists are simply sampling bits and pieces of the model line-up and trying to sort out the relationships and timing of their origin.

This, of course, is nothing new. The same situation occurred with Archaeopteryx, a representative of a species or group of species that were clearly reptilian in origin but had developed a number of birdlike traits, including flight feathers. The fact that we have since found earlier "true" birds does not diminish Archaeopteryx's status as a transitional form ... it is an organism that arose from ancestors inhabiting one environmental niche (land animal) and in the process of entering another (flying animal). Nor is it important whether or not Tiktaalik is a direct ancestor of modern tetrapods or Archaeopteryx is a direct ancestor of modern birds. Given the "bushy" nature of evolution, which tends to throw up a number of forms when some group finds a new niche open to them (witness our own multiple possible ancestors), it wasn't all that likely that Tiktaalik was a direct ancestor of tetrapods. In fact, the animals that made the tracks in Poland are also unlikely to be direct ancestors of modern tetrapods. Its line may well have died out with no modern descendants. So what?

Luskin's "argument" depends on there being one and only one transitional form extant at any one time.

But think of what such situations say about Luskin's God ... opps ... "Designer." Why design all the various proto-tetrapods and proto-birds only to see them go extinct? More importantly, why all the proto-humans and other apes? And what's to say we aren't as ready for "the "Designer's" ash heap as Tiktaalik and Archaeopteryx?


* Read the news stories Luskin links to in order to see how real scientists react to such findings ... with a mix of caution and excitement at the opening up of new avenues to explore ... rather than taking a cue from Luskin, who buries his fingers deeper in his ears, screws his eyes tighter shut and hums "Nearer My God to Thee" even louder.


Update: PZ demolishes Luskin.

I am amused by Luskin's willingness to abandon his normal hyper-skepticism towards fossil evidence, but only when that evidence indicates that our current understanding of evolution is incomplete.

It's a near certainty that if the age of these footprints was supportive of the traditional view of tetrapod evolution, Luskin would be referring to them as "alleged footprints" or disparaging them with some other doubt-inducing phrase.

As it stands, he apparently fully accepts their validity as "unambiguous footprints (with digits) of a full-tetrapod."

Absolutely clueless.
"rather than taking a cue from Luskin, who buries his fingers deeper in his ears, screws his eyes tighter shut and hums "Nearer My God to Thee" even louder."

Part of the sandwich I was chewing on while reading this sentence is in my nasal cavity now. Thanks.

The moment I read PZ explain the findings, I just *knew* the creationists would use this to do to deny that Tiktaalik is a *real* transitional fossil, just as they did with Archaeopteryx. Disappointed to see I was right, though.
Sorry about the sandwich but I really think you have to blame Casey for that. I report, you decide ... to swallow or not.

Creationist6s have never understood ... or, at least, never professed to understand ... the import of transitional fossils. Its never been about tracing the line of descent but about showing how descent could have happened.

Jeremy's point is well taken. Casey's and the DI's disingenuousness is displayed for all to see by how they accept without criticism the results they like and disregard any that they don't.
To be fair to the Creationists (much more so than they deserve), media reports of new fossils often present them as possible new ancestors (climbing that ladder from slime to Europeans) rather than providing the fuzzier picture of cousins, siblings, aunts and uncles.
One of the more counter-intuitive parts of evolutionary theory, I think, is to think of species as populations rather than as 'kinds'. The problem is compounded when one takes into consideration that fossils are always of individuals, except in very rare cases. The scientific understanding of a 'transitional form' is based on the deeper insight that species are populations, not kinds. Most people don't really appreciate this, and creationists have a vested interest in making sure they continue to not appreciate it.
Umm.. what 'earlier "true" birds' did you have in mind?
Umm.. what 'earlier "true" birds' did you have in mind?

Uh oh. I sort of ... um ... winged that. I thought I remembered that there were earlier fossils discovered with, particularly, keeled breastbones and maybe beaks.

Now you're going to point out my swiss-cheeze memory, aren't you?
I need to set myself up a little stand with an electronic marquee scrolling all the blog posts, articles, etc. demolishing this nest of buffoons. They're sullying my city. It'd be nice to cause them some discomfort in turn.
To discomfort someone they need to have some shame.
I sort of ... um ... winged that.

Owch! I'd forgotten that you're in the same league as Wilkins with these word games.

Now you're going to point out my swiss-cheeze memory, aren't you?

Only if you want me to. Unfortunately, "bird" isn't a very precise term, and there's even uncertainty about the meaning of "Aves". Hence, my question.
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