Quagga, Zebra, donkeys and horses are all Equine's.
"Equine" is not a species.
Equus, which you may be thinking of, is a
genus, containing the different species you've mentioned above.
Claiming this to be some sort of empirical evidence of transspecific evolution is like using a German Shepherd and a wolf in the same way in the bag of evidence.
Right. German Shepards and Gray Wolves are two different species. The fact that one evolved from the other is proof of what you call "transspecific evolution." What else would the evolution of one species from another be expected to prove?
Evolutionary biologists are not content, however, on merely explaining how variations occur, but aspire to answer a much broader question. They seek to explain how all of life began in the first place.
No, they really don't. The origins of life is the province of biochemists, because the origin on life is a chemical problem.
Evolutionary biologists study the history and diversity of species on Earth.
How is it that individuals who pride themselves on their pragmatism and empiricism, continue to follow such an unempirical theory?
Isn't that a pretty powerful indication that you're wrong about evolution? That the evidentiary basis for the theory you dismiss is considerably better developed than you're prepared to admit?
Undoubtedly, there are powerful alliances with a vested, interest in the propulsion of this untenable theory.
Ah, right. Conspiracy theories.
That's always a convincing argument.
Take for example the canine family.
Canidae is a family that contains wolves, dogs, foxes, and jackals. It's a very ancient family that has grown to include a large number of species that cannot possibly interbreed, thus providing a handy proof of macroevolution and the power of random mutation and natural selection to result in completely new species.
Likewise, botanists have breed many different types of roses, varying in size, shape, and color; but, as the saying goes, ”a rose is still a rose by any other name.’
Which disproves the idea of using common names as a basis for species identification. But for some reason, you persist in doing so. You will not understand how evolution is possible until you understand the organization of living things, and you cannot do that merely by looking at what organisms are
called.