[reasonisfaith]

I think one major problem we’re having here is that neither the genetic nor the evolutionary processes of speciation can be precisely described.

[allmendream]

I think one of the major problems you are having is that you don't understand the processes of speciation AT ALL, even after I have described it to you.

I described, precisely, how DNA replication is not 100% accurate, and thus it introduces germline changes. I described to you that these germline changes passed down from parent to child introduce variation into a population. Darwin described, accurately, how natural selection acts upon such variation.

Now if we observe a 0.001% change in a population over 20 years, what is going to stop it from becoming a 1% change in 20,000 years?

If two populations with that rate of change are separated for 20,000 years; why would they not be some 2% different in DNA between them? Why would this 2% difference not be sufficient to call them two different species?