Birds are dinosaurs: Simple answer to a complex problem

Auk, The, Oct 2002 by Feduccia, Alan

One thing is certain, if one begins to "cherry-pick" characters within the advanced groups of theropods to establish bird origins, then the door is open for the same procedure in other groups as well. Dodson (2000:504) rightly emphasizes that,

Cladistics systematically excludes data from stratigraphy, embryology, ecology, and biogeography that could otherwise be employed to bring maximum evolutionary coherence to biological data. Darwin would have convinced no one if he had been so restrictive in his theory of evolution.

Phylogenetic systematics stands alone in the sciences in demanding that critics of a particular phylogenetic hypothesis not criticize the hypothesis without proposing an "explicit alternative hypothesis" (Prum 2002:1). Another way of stating that philosophy is that, "a flawed hypothesis is better than no hypothesis at all." That approach does not conform to any standards of science. There are times when there is insufficient evidence to make the formulation of a hypothesis feasible.

According to Dingus and Rowe (1998:194), ". . . birds are avialian, maniraptoran, tetanurine, theropod, saurischian dinosaurs." However, as Bock (1999:568) recently cautioned, "it is best to consider birds as part of the great archosaurian radiation without being more specific, as has been agreed by zoologists for more than a century." Thomas and Garner (1998:130) question why the debate over the phylogenetic position of birds seems far from any conclusion, and note that the reason may be, "Perhaps because where natural selection meets the strict constraints of biomechanics, convergence is inevitable, and separating common inheritance from common function may be near-impossible in a system so highly derived."

Acknowledgements.-For discussion and clarification on important scientific issues I thank W. J. Hillenius, L.-H. Hou, T. D. Jones, M. Kundrat, T. Lingham-Soliar, P. E A. Maderson, L. D. Martin, S. L. Olson, J. Ruben, and Z. Zhou. S. Whitfield helped with preparation of the illustrations, and T. Lingham-Soliar provided illustrations for Figure 5. DinoData can be accessed online at www.dinodata. net.

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