First, there are not mountains of evidence for evolution. There are mountains of fossils, but precious little evidence for evolution beyond microevolution. No transitory fossils at all. All those so far claimed to be transitory have turned out to be frauds or like Archaeopteryx a full blown flying bird. The fossil had fully developed flight feathers, nothing transitory about it.
Secondly, it only requires a leap of faith if you believe that we are alone in the universe or at least the most advanced creatures in the universe.
First of all, this is where you have overeached your expertise. I am a geologist, and am published in the Journal of Paleontology. I read as man issues as I can afford, which is quite a lot. In the 1990s, three of my colleagues and I discovered 8 new species of extinct Mississippian-aged crinoids, which were described over the coarse of several years, and then published in 2000. Along with those newly described species, where dozens of species for which only a handful, and in a few cases, only one other known extent specimen.
And we not only decribed new species, but an entirely unknown faunal collection (some 30 genera, and 72 ne species in a colection of nearly 450 speciments) insitu, enclosed in sedimentary structures in the limestone that demonstrated that the collection consisted of a local reef that had been subjected to numerous huge storms (the sedimentological term for rocks that contain these structures is "tempestites") over a period of hundreds of thousands of years. And this reef is now considered to be one of the most diverse crinoid reefs ever found. The diversity includes all three classes of crnoids, which is itself unique, because crinoids are classified based partially on the energy of the environment in which they can sustain themselves. Crinoids are filter feeders, and so have certain current requirements in order to feed. What's more, their strucures are such that some crinoids can only survive in a slow current due to their fragile nature. Others can withstand very intense currents and even ocean floor scouring at storm wave base. Then there is a transitional class that is less delicate than some, more stout than others, and yet can survive in all but the worst currents.
What was unique is that all three classes were found in a location that experienced very strong currents and even large, likely hurricane force currents. This had never been seen before, and even more interesting is that in this environment, all three classes thrived, many attaining very large sizes. This can only have occurred if there had not been ongoing adaptation to the environment in which they had been subjected, because it is clear that many of these fragile animals have never been seen in such environmental conditions. What was found was that they had adapted in a way that prevented either their calyxes from easily being ripped off the stems, or their holdfasts were more robust that was seen elsewhere. This is a classic example of evolution on both microevolutionary and macroevolutionary scales. For there are indeed trasition species in this collection, and those species are all inadunates, which is what would be expected, since they are the generalists of the three classes.
That said, the fact is that all species are, by the very nature of evolving, transitional species.
