The criticism by creationists and IDers that we do not find transitional forms in the fossil record is, to them, one of the most damaging arguments against evolution by natural selection. I suggest that the expression - ‘transitional form’ - derives from trying to impose on Nature, man-made abstractions that are meaningless to her. Nature does not think in terms of evolution from one (sign-post) SPECIE to a new (sign-post) SPECIE. The SPECIE - gray wolf - of today may be a different SPECIE from the ancestral one of 30,000 years ago, and that one may be a different SPECIE from the one of 60,000 years ago, but what about the ancestral SPECIES of 10,000 years ago, or 20,000 years ago? Just as the 30,000 year old SPECIE might be infertile relative to today’s, could the 10,000 year old SPECIE also be infertile with respect to that of today? Suppose that it is not, but that the SPECIE of 15,000 years ago is. What great significance is there to this? I could have chosen my two SPECIES of comparison as, one at 15,000, and, one at 30,000, years ago, respectively, assuming that that at 15,000 and that at 30,000 are relatively infertile. So, is not the time interval rather arbitrary, and, is not the point of departure not also inconsequential? I could have started 2,000 years ago instead of today. Clearly, there are well established SPECIES at the IN-BETWEEN POINTS! My conclusion is that the concept, SPECIE, is a fabricated one that we use due to our wired need to abstract. Now, with respect to the fossil record, any morphological differences that we could expect to see are likely not to happen except as they occur at the large time intervals of real excavation. In other words, we should not expect to find two specimens separated by small intervals of time! Thus we should not expect to find sufficiently small morphological differences which the other side could claim are in A TRANSITIONAL RELATION!
just a few reminders from the local taxonomist: 1. The word 'Species' is singular and plural. 'Specie', means nothing. 2. You are correct in identifying the gradualness of speciation. 3. Welcome to EvC!