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The Origin and Evolution of Birds. Alan Feduccia. xii + 420 pp. Yale University Press, 1996. $55.
The popular press seems perpetually confused by the intense debate over how birds and their flight evolved. Did birds originate within small carnivorous dinosaurs or from an as yet unknown, more distant reptilian group? Did they climb trees and glide on the way to flight, or did they run and jump from the ground, extending their leaps by flapping their incipiently feathered forelimbs? Is there any real evidence bearing on these questions, or are they just matters of acrimonious debate among scientists, each with part of the puzzle? Is any progress being made?
In fact, this problem is not different from most others in science, and the solution is the same. Science depends not on authoritarianism, not on hegemony of single fields, and not on majority votes, but on method. Progress is made not only as more evidence accumulates, but also as methods of analyzing evidence are developed, tested and standardized. The difficulty of the present debate is that the methods used by the rest of the community are not used by a few who still object not only to those methods but to their results. In their place, however, the dissenters offer no methods and no opposing theory that can be tested; their theory amounts to an objection to the accepted theory. So it is very difficult for the rest of the community to evaluate or test these objections. But to those not familiar with the evidence and methods, the whole issue can appear to be only a pointless squabble.
In The Age of Birds (Harvard University Press, 1980), Alan Feduccia first laid out his arguments that birds did not descend from theropod dinosaurs, as commonly accepted, and that flight must have evolved from the trees down. In The Origin and Evolution of Birds Feduccia fights hard against accepted relationships and the methodologies used to reach them-now generally preferred by the systematic community, including reviewers for the systematic division of the National Science Foundation. How well he succeeds may depend on how much the individual reader knows about the issues and methods to begin with.
The book can be seen in three parts: the origin of birds...