So Is Archaeopteryx a Transitional Form, Or Not?
An international team set out to determine if the skull features of Archaeopteryx, the famous fossil bird, indicated whether it was capable of flight. The answer reported in Nature1 was affirmative:
Here we show the reconstruction of the braincase from which we derived endocasts of the brain and inner ear. These suggest that Archaeopteryx closely resembled modern birds in the dominance of the sense of vision and in the possession of expanded auditory and spatial sensory perception in the ear. We conclude that Archaeopteryx had acquired the derived neurological and structural adaptations necessary for flight. An enlarged forebrain suggests that it had also developed enhanced somatosensory integration with these special senses demanded by a lifestyle involving flying ability.
Everything they measured was within the range of characteristics for modern flying birds. For instance, they say: “Birds with the same body mass as Archaeopteryx have from one-third (for example, galliforms and columbiforms) to five times (for example, psittaciforms and passeriforms) bigger brains. However, the brain of Archaeopteryx is about three times the volume of those of non-avian reptiles of equivalent size.” The scientists say nothing about transitional forms, and only make this one indeterminate statement about evolution: “it has remained contentious whether brain size increase was tied to the evolution of flight, arboreality, or other environmental influences,” hardly an affirmation that birds evolved from reptiles.
A very different conclusion was reached by reviewer Lawrence Witmer (Ohio U), who calls Archaeopteryx “the near perfect transitional form.” Since Darwin’s Origin of Species was published, he says, “it has been a compelling example in the case for evolution.” Witmer understands that the requirements for flight are pretty demanding: “But flight isn’t just about wings, rudders and flaps,” he says; ”It’s also about the pilot and on-board computer, and those are the missing elements that this new study provides for Archaeopteryx.” Nevertheless, he concludes, “This latest in a long line of papers on Archaeopteryx affirms the iconic status of this fossil” (i.e., as a classic transitional form between reptiles and birds).
See also the MSNBC and National Geographic slants on this story.
1Patricio Domínguez Alonso et al., “The avian nature of the brain and inner ear of Archaeopteryx,” Nature 430, 666 – 669 (05 August 2004); doi:10.1038/nature02706.
2Lawrence M. Witmer, “Palaeontology: Inside the oldest bird brain,” Nature 430, 619 – 620 (05 August 2004); doi:10.1038/430619a.
A more shameless example of spin doctoring by a Darwin Party hack could hardly be found. The evidence showed that Archaeopteryx not only had the wings of a bird, but it had the skull of a bird, the eyes of a bird, and the pilot and onboard computer of a bird. And he has the audacity to say this confirms it as a near-perfect transitional form between reptiles and birds! Speaking of icons, Witmer needs to read ch. 6 of Icons of Evolution, where Jonathan Wells puts this fossil in its place. (Click here and here for summaries of his arguments; TrueOrigin has an article by Ashby Camp on Archaeopteryx and the supposed evolution of birds from reptiles.)