Ben,
Thanks for the feedback.
So it is up to me to disprove my hypothesis of dramatic mutation outside of natural mutation and selection is what creates species. If my hypothesis were false, then I would propose that we should be able to witness some speciation today due to the number of species that exist on the planet.
Researching this point further, I see that it is suggested that finches on the Galapagos islands have been witnessed to form a new species, theoretically by cross-breeding with a land species that flew onto the islands. The physical differences in the beaks are cited. However, if it is a new species, they should not be able to create viable off-spring and yet they can.
So it remains, where and how can we witness a species breeding and creating a mutation such that it becomes a unique species that can no longer inter-breed and create viable offspring with the original species? Perhaps you have to look at a birth of finches from different genetic pools (land finch cross-breeds with an island finch) and then in the same nest male and female offspring are hatched can only breed among each other. Then you have a new species. If this were witnessed, then it would indicate that the hypothesis is false.
If it has not been witnessed, then why not? The only reason that would disprove the hypothesis is if the odds of this happening in one species on our planet during our life time is so low? I think not but admit I don’t know the odds.
You state that physical changes are often the basis of speciation, and we should stick to populations instead. I’m not sure I understand. Certainly a Chihuahua and a Great Dane have different physical characteristics, but still are dogs. They would not naturally inter-breed but if they did they would be successful at producing viable offspring. We have to have one definition of species do we not? What is yours?
Finally, you say DNA evidence does not support my hypothesis. But does it disprove my hypothesis?