More birdlike behavior in theropod dinosaurs

March 19, 2009 • 8:43 am

In WEIT I describe and show a picture of birdlike sleeping behavior in theropod dinosaurs: a fossil was discovered of a therpod sleeping with its head tucked underneath its forelimb (and tail curled around), a posture nearly identical to the sleeping posture of modern birds. Now an article has appeared in PLoS (Public Library of Science) showing even more birdlike behavior of theropods: “Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace,” by Andrew R. C. Milner, Jerald D. Harris, Martin G. Lockley, James I. Kirkland, and Neffra A. Matthews, which you can find here.

It turns out that Milner et al. uncovered several sets of theropod tracks from fine Utah sandstone about 198 million years old. They show the impressions of theropods of the species Eubrontes gigante and Dilophosaurus wetherilli walking (and dragging their tails), as well as resting on both hind AND front legs. (Front-leg impressions are rare in theropods since they were obligately bipedal.) When the beast rested, it brought its hindlimbs (manus) together symmetrically (in line) and rested its forlimbs (pes) on the ground, with the hands pointing inwards (see the impressions in the original article showing handprints). The authors conclude that theropod hands always faced inwards when the arms were stretched out–a configuration identical to that of modern birds. Apparently the palms-in position evolved very early in the theropods, presumably to help them grasp prey.

The more we learn about theropods, the more we see that many of the features that were later co-opted in flight were “pre-adaptations”–that is, traits evolved for one use in the theropods that were later hijacked for flying by their bird descendants. Another such feature is feathers, which we’ll discuss tomorrow. Clearly, the evolution of birds from dinosaurs was not as mysterious and maladaptive as touted by creationists. As is usual in evolution, new adaptations are simply old ones that have been refashioned.

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Reconstruction of the theropod Dilophosaurus wetherilli resting after having walked on mud. Note inward-facing palms. See original paper for the tracks that led to this reconstruction. Drawing taken from Milner et al. paper.

Holiday snap: the Jesus Christ lizard

March 18, 2009 • 2:43 pm

This is a green basilisk lizard (Basiliscus plumifrons) that I saw on my recent “lecture cruise” to the Caribbean.  This specimen was in the vegetation lining the Tortuguero Canal near Puerto Limon, Costa Rica.  These basilisks are endearing because, with their striking crests, they look for all the world like little dinosaurs.  They are called “Jesus Christ lizards” because they can actually run over the surface of water for up to 5 meters at amazing speed. They do this by slapping their splayed, filamentous feet hard against the water surface, which creates air pockets that keep them from sinking. I have seen them do this, and it’s incredible.  Another marvel of evolution!

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Here’s a great slow-motion video of another species of basilisk running on the water. Pretty amazing. . .

Domestication of horses: a New York Times editorial

March 18, 2009 • 8:08 am

Today’s New York Times has an odd opinion piece which begins, correctly, with the recent discovery that horses were domesticated about a thousand years earlier than previously suspected, since findings of pottery containing traces of horse milk from 3500 B.C., as well as horse skeletons from Asia, suggest (see original paper in Science magazine) that the inhabitants of central Asia had modified the skeleton of wild horses through domestication, making it less robust, and also were using mare’s milk as food. Preumptive bit wear on the ancient horses’ teeth also suggest domestication. All well and good, and an excellent example of forensic archaeology. However, the Times goes on to say this:

This discovery pushes back the date for a hugely important technological change in human existence. But it’s also a reminder that domestication isn’t just the conquering of one species by another. It’s the willing collaboration between two species, a sharing of benefits. There is something in the equine nature — genetic or social — that allowed it to partner with humans, just as there was in the character of dogs.

Well, of course there was something in the nature of horses that enabled them (unlike many other wild animals) to be successfully domesticated. But what on earth suggests that the domestication was “willing” and a “collaboration”? What do the horses get out of it? Maybe some food, but to me it looks more like animal slavery–indeed “the conquering of one species by another.” Let’s not kid ourselves.

Philip Skell’s creationism disowned by his own family

March 18, 2009 • 6:20 am

In an earlier post, I discussed chemist Philip Skell’s attack on evolutionary biology and my own defense of it in Forbes magazine.  Now a member of his own family has written in disowning Skell’s ludicrous ideas.  Here is  a response to Skell’s post I  just received from one of his relatives (n.b. Skell is a member of The National Academy of Sciences, which apparently doesn’t require members to evince a general ability to evaluate evidence!)

Faulk Jr.
Posted March 17, 2009 at 8:55 pm | Permalink (Edit)

While natural selection and evolution are different matters, if they truly are, that does not change the fact that things have the ability to adapt and change as they are exposed and that the only way they can do that is by changing the manner in which they are structured. I find it hard to believe that appendages that look like vestigial arms and the like were put there because a higher being thought they would be useful, even though they are quite useless. If everything were developed by a supremely intelligent being then there would be nothing extra that was without a cause. All beings would be streamlined, sleek, strong, fast and perfect. Pick any animal you want and there are obvious errors with it. It is not simply enough to say that evolution isn’t valid and therefore creationism is. What you need to do, Mats, is prove that things in fact didn’t evolve but were designed by a creator. When there is scientific proof of this then the creationists will be left alone. And it is worth noting that Skell is the only person in the family who actually holds these values. The rest of us think it is absolutely absurd.
-Thorin Faulk

WEIT reviewed in Christian Science Monitor

March 16, 2009 • 2:45 pm

by Greg Mayer

Why Evolution is True receives a favorable review today in the Christian Science Monitor from Todd Wilkinson.  Money quote:weit-cover1

Coyne methodically lays out the complete trail of evidence supporting evolution, ranging from the fossil record of dinosaur bones to sophisticated DNA analysis, and many decades of rigorous peer-reviewed scrutiny in between.

In this 200th anniversary year of Darwin’s birth, “Why Evolution Is True” ranks among the best of new titles flooding bookstores….

He makes the case for evolution in a way that is eminently understandable, colorfully articulated, and relevant to our time.

Update: Jerry and I were apparently writing posts on this review simultaneously, so I didn’t see his post till mine went up.  If I knew how to delete a whole post I would, but I don’t know how!

WEIT reviewed in Christian Science Monitor and Nature

March 16, 2009 • 1:39 pm

This past week two reviews of WEIT have appeared, one in the Christian Science Monitor, which includes an attached podcast (click under the cover icon), and one by Eugenie Scott in the scientific journal Nature. Both are pretty positive, I think, though, that the Nature review is quite tepid. I suspect that one reason for this is that I have angered the National Center for Science Education (Genie Scott is its executive director) by claiming that science and faith are largely incompatible. The purported compatibility of these areas is a keystone of the NCSE’s strategy for selling evolution in the public schools, and the organization has a history of being diffident towards scientists who question such religious accommodationism, either in principle or as a tactic for getting evolution into the schools. The NCSE even has a “faith project” for demonstrating that faith and religion are compatible. My own view is that an organization designed to defend the teaching evolution should do just that and only that, and should stay away from religion completely.

There is one issue Genie Scott brings up that I want to respond to. She says this in her review:

A book for the public must simplify, but there lurks the possibility of subsequent distortion. Many people misunderstand evolution as a great chain in which simple forms evolve into more complex ones, rather than the branching and extinction of lineages. Amphibians did not evolve into reptiles, and reptiles did not evolve into mammals and birds. Rather, a population of early tetrapods — four-legged vertebrates — gave rise to a diverse group of organisms that included ancestors of modern frogs and salamanders, and to a separate branch characterized by having an amniotic egg. A primitive amniote gave rise to reptiles and birds on one branch, and mammals on another. Given that the branch leading to mammals preceded that leading to reptiles, it is misleading for Coyne to use the outmoded term ‘mammal-like reptiles’ instead of ‘non-mammalian synapsids’.

Well, this is a dispute about whether the common ancestor of mammals and reptiles could be considered a reptile, which many cladists don’t since the group “reptiles” must include ALL the descendants of a common ancestor. But if the common ancestor has many diagnostic characters of a reptile, then why not call it one? If you followed Scott’s line of reasoning, you could not say that the ancestor of modern amphibians was a fish, since the category “fish” must include the ancestral fish and ALL of its descendants. But everybody calls early lobe-finned fish “fish.” This criticism, I think, is pretty trivial.

Videos from WEIT collected in one place

March 16, 2009 • 1:24 pm

The author of the blog “Evangelical Agnosticism” has kindly collected most of the videos that I referenced in WEIT and put links to them in one place. Several of them, I think, are must-sees, including the water chevrotain, the gliding ants, and the honeybees cooking an Asian wasp to death. They are all given in the “notes” at the end of my book, but rather than copying in the links, you can just click on them here.ll