Pigeonholing the “Dino-birds”

Abstract

One of the central claims of the intelligent design movement is that certain features of biological organisms are “irreducibly complex,” with such tightly integrated components that removal of any one part renders the system incapable of functioning. The existence of irreducibly complex structures has been repeatedly put forth as evidence against evolution via natural selection, on the grounds that such a system could not be assembled incrementally over time. Although most irreducible complexity arguments deal with the molecular and cellular levels, such as the vertebrate blood-clotting response or the bacterial flagellum, a common organismal-level target has been the evolution of feathers and flight in birds. Those who accept the existence of “dino-birds” need little convincing that the avian flight apparatus is not irreducibly complex. This chapter uses the close relationship between theropod dinosaurs and birds as a framework to discuss how systems of classification profoundly affect our views of the relationships between organisms.