The theory of evolution supposes that the first chordates like pikaia turned into fish over time. But no intermediate-form fossil has been found to substantiate the claims about chordate evolution, therefore, there is no fossil to support any claims of how fish evolved. On the contrary, all classes of fish appear all at once in the fossil record, with no preceding ancestors. The evolutionist paleontologist, Gerald T. Todd, in his article entitled "Evolution of the Lung and the Origin of Bony Fishes," lists the following unanswerable questions that this fact raises: All three subdivisions of bony fishes first appear in the fossil record at approximately the same time. They are already widely divergent morphologically, and are heavily armored. How did they originate? What allowed them to diverge so widely? How did they all come to have heavy armor? And why is there no trace of earlier, intermediate forms? (Gerald T. Todd, "Evolution of the Lung and the Origin of Bony Fishes: A Causal Relationship," American Zoologist, Volume 26, no. 4, 1980, p. 757.)