I don’t really have anything to say about the larger debate here (haven’t seen “Expelled,” I like Ben Stein, seems like a nice guy, but it sounds like he might be in a little bit over his head here, i.e. he’s not trained in the sciences, mainstream or otherwise) or about any finer points of theological thought (except that the first papal support of evolution as a valid scientific theory not at odds with Catholicism when it applies to strictly biological matters came in 1950, in Pius XII’s encyclical Humani Generis, which is certainly pre-Vatican II).
Instead, I just have to address the recurring argument against evolution that asks “where are the transitional fossils?” They are everywhere. Literally. There is not a patch of fossil-bearing earth that does not contain, in some form, a fossil that represents a transitional form of some kind. The only difference between “macroevolution” and “microevolution” is geologic time. Small changes become, under the right circumstances and with enough time, big changes - changes large enough to separate species from their forebears. The “where are the transitional fossils” argument always devolves into a hair-splitting exercise. Example: Scientists theorize, due to shared characteristics, that birds evolved from reptile ancestors. A fossil is found that blends reptilian and avian characteristics, providing a snapshot of this change. For most people, this would count as evidence for that particular theory, especially as more and more of this sort of fossil, and others like it, are found. The “macroevolution” argument then shoots back, “Yeah? Well, where are the transitional fossils between Species A and Species B?”
Again, everywhere. The fossil record is a collection of scattered portraits that requires paleontologists to piece together history like a collage, but every once in a while they are lucky enough to find a place where it runs more like a filmstrip, showing every step of the process. Case in point: shark teeth are the most numerous vertebrate fossils on the planet, due to their continued production in a shark’s mouth, their durability, and the presence of sharks on this planet for 400 million years or so. In several places on earth (South Carolina, Peru, Morocco, Kazakhstan, the Chesapeake Bay) there are sedimentary deposits that seamlessly represent 10-50 million years of seabed stacked in nice, orderly layers. In these layers are teeth that show the tiny, at times imperceptible changes that eventually result in speciation. A Late Pliocene shark, Isurus hastalis (and I am entering controversial waters here, as some prefer the genus name Cosmopolitodus, some Carcharodon, but anyway) starts developing small nicks along the sides of its broad, smooth-edged teeth late in the Pliocene. These irregular nicks become larger and more regular as the teeth move upwards through time, until finally around the Pliocene/Pleistocene border these teeth have become recognizably Carcharodon carcharias, the modern Great White, with its large, complete, regular serrations. What to call the intermediary teeth, with the irregular serrations? They have been labeled Isurus escheri, but trying to figure whether a tooth is a somewhat jagged hastalis or a smoother that usual escheri becomes difficult. This phenomena is not limited to this one transition, either; the decent of dozens of genera and scores of individual species can be traced, in a seamless and continuous fashion, in these sediments, and the uniform and undisturbed sedimentary deposits that yield them make it possible to see the individual teeths’ relative position to other teeth that came before or after very simple. These deposits also hold portraits of ray, whale, dugong, crocodile, and invertebrate evolution as well.
Basically, even ignoring genetics, biogeography, and comparative anatomy, one could make a remarkably strong case for one species becoming another one or more species based on paleontology alone. Either sharks somehow operate outside of the rules that govern the rest of life, or these rules apply to life universally.
Does this have anything to do with the fact that Christ dies for our sins, and through him all mankind can enjoy eternal life? Nope, not at all.
No “continuous discussion,” because there has been nothing to discuss.