[js1138]

You don't usually need to wait on random mutation. Most populations maintain a significant amount of variation at any one time, and thus can respond, often on time scales of a few years or less, to sufficiently extreme selective pressures.

Some populations more than others. DNA studies indicate that dog breeds are less than 300-400 years old. If all you had of dogs were multi-million year old fossils, you would be amazed at the rapid "evolution" of dogs. Quite enough to be labeled separate species.

Suppose all you had were fossils of wolf and Chihuahua. There would be a huge gap in a geologic eyeblink.

[onewhowatches]

Suppose all you had were fossils of wolf and Chihuahua. There would be a huge gap in a geologic eyeblink.

=======

Wolf mating a Chihuahua! Now that's a stretch!