Sky writes:
If there are no limits, then why are there no "sliding scale" series at present?
Start with a population that gets divided in half. Since they now go their separate ways they can diverge from each other genetically. As each changes with time they become different/distinct until they no longer can interbreed etc.
So why aren't there existing variations between them? Why does the ToE predict that there should be?
The sliding scale occurs over time not over space, with the exception of ring species which do both.
There is no connection between the two groups that requires what you demand.
Take the original population and divide into 10 groups. Isolate them. Now we would expect them to become equally divergent one from another, not a gradual gradation from one extreme to another between them.
Is this your thought and objection or something you read w/o thinking about it in creationist literature?