Page 34 - The Origin of Birds and Flight
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32                   The Origin of Birds and Flight

                    Professor Alan Feduccia, of the North Carolina University Biology
                 Department, recognized as one of the world's most eminent authorities
                 on ornithology, describes the theory as “aerodynamic absurdity.”  11
                    Some 50 years later,  Yale University Professor of Geology John
                 Ostrom proposed a new version of the cursorial theory, suggesting that
                 forearms turned into wings as they attempted to capture insects.
                 According to Ostrom, feathers first emerged for insulation of body heat
                                            12
                 and later extended in length. This “insect theory” came in for criticism
                 on four major grounds, and in 1983 Ostrom was forced to reject his own
                 theory. In one statement, he cites the absence of the intermediate forms
                       13
                 his theory required:
                    No fossil evidence exists of any pro-avis. It is a purely hypothetical pre-
                    bird, but one that must have existed.  14
                    Those eager to continue with the theory after Ostrom suggested that
                 feathered wings developed in order to control the body’s direction dur-
                 ing running and leaping. Like their predecessors, however, these men
                 too came in for criticism.  15  For instance, Professor Jeremy Rayner of
                 University of Leeds calculated that when a living thing in this hypothe-
                 sis jumped up into the air, there would be a 30 to 40% drop in its speed
                 which would cause serious problems in flight. Rayner came to the con-
                 clusion that under such conditions, a considerable amount of energy
                                                                           16
                 would be required which would mean a very low flying speed. Rayner
                 therefore suggested that the model was lacking in the morphological,
                 physiological and behavioral features required for flight, and that it
                 would therefore fail.   17
                    Despite changes brought in, the Museum of Texas Technical
                 University paleontologist Sankar Chatterjee was forced to accept that
                 the cursorial theory was bio-mechanically untenable.  18
                    David E. Fastovsky, a professor of earth sciences and a paleontolo-
                 gist, and the cellular biologist and anatomist David B. Weishampel of
                 the John Hopkins University Medical School, stated that functional
                 morphologists have been unable to satisfactorily model the running-to-
                 flight transition in early birds.  19
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