As explained by Behe, a bicycle has nothing that can be modified to become a gasoline tank, for example. Darwinian evolution requires physical pre-cursors. As an example, Denton discusses mammalian hair, and points out that there is no evolutionary pre-cursor. Or consider the metamorphosis of the butterfly. There is no conceivable evolutionary precursor to this astounding event.
Biology is fraught with such problems for evolution.
The Problem of Molecular Isolation Denton also devotes a detailed chapter in his book about the biochemical matrix of organisms. No classes are intermediate or partially inclusive of other classes. Denton believes that this information is so devastating to the theory of evolution, that were it known when the theory of evolution was being developed, the idea of organic evolution would never have been accepted. If evolution were true, we should find a few simple lifeforms in the lowest level of the geologic strata, with a consistent upward progression of lifeforms of a more advanced nature in the next highest strata, etc. But we don't find that at all.