In addition, many dogs cannot produce viable offspring if mated with a wolf. I would say my Shitzu is not the same species as a dog.
As for man, the bigger you get, the longer it takes. And, if you think that Austrailian aboriginese and Swedish people don't show the results of geographic isolation - you're on a different planet.
Furthermore, many dog breeders destroy "non conforming" traits within the breed - they are trying to weed out the genes that would cause change.
It doesn't matter if, say, a shoe salesman or an Oom Paul Kruger believes the world is flat or doesn't believe in evolution.
In our free society he can even argue with a scientist. It is a waste of time if the scientist argues back.