If evolution was true, why don't we see a mishmash of species?

"If Darwinian evolution held any weight, what we ought to be seeing around us is a mishmash of man-panzees, and man-gutans and not a clearly formed species of each organism. This discontinuity is confounding." This was the dilemma my friend Sharath raised while we were engaged in another of our heated debates on 'nothing-in-particular'.

Intriguing. I thought, but the wonder held only for a moment. My high school biology came flashing back and I had an epiphany of sorts. It goes something like this

'While species(Let's say Ninja turtles) were evolving, the heritable changes happened in the germplasm and not the somatoplasm. One such genetic change, led to a modification of the reproductive anatomy of a few organisms in a species thereby making them reproductively isolated from non-mutants.

In other words,these mutant ninja turtles :) could fruitfully mate only among themselves(mutants) as any cross mating with non-mutant versions would lead to no offspring or a sterile offspring. Now by virtue of this single reproductive mutation, the mutant-ninja turtles mated and evolved into a new branch in the evolutionary tree. Very disparate from their uncle's nephews and nieces. The end product if viewed as a snapshot in time(In the evolutionary timeline our lifetime would be less than a snapshot) ,would be a collection of independent and disparate species with no apparent link to each other. Which is what we see today. Voila...Darwin stands vindicated!!!