Your argument about Hawaiian Drosophila is fascinating.
You say that the flies are all Drosophila, so no real evolution
has occured. Consider the following. Morphologically, some
of the Hawaiian species are dramatically different from, say,
Drosophila melanogaster. But the real key is genetic. In the last
one million years approximately, the Drosophila species in the
Hawaiian Islands have gone through about 10,000,000 generations.
In the 5 to 7 million years since humans and chimpanzees shared
a common ancestor, fewer than 500,000 generations have passed.
One might therefore expect that the measured genetic distances
(Nei's method or any of the other widely used methods) between
some species of Hawaiian Drosophila would be greater than the
measured genetic distances between humans and chimpanzees.
Thus on both morphological and genetic distance scales, Hawaiian
Drosophila have undergone greater evolutionary changes than that observed
between humans and chimpanzees. If all Hawaiian Drosophila are merely
flies that have undergone no significant evolution, then there is no significant
evolutionary change between humans and chimpanzees. I suggest you look
at Drosophila heteroneura as a start, and see if you still think no evolution
has occurred in Hawaiian Drosophila.
Best wishes, Will Provine