Genetic Upper Class: Could the Human Race Split?

The Upper-world people might once have been the favoured aristocracy, and the Morlocks their mechanical servants: but that had long since passed away. The two species that had resulted from the evolution of man were sliding down towards, or had already arrived at, an altogether new relationship. The Eloi, like the Carolingian kings, had decayed to a mere beautiful futility. They still possessed the earth on sufferance: since the Morlocks, subterranean for innumerable generations, had come at last to find the daylit surface intolerable... Ages ago, thousands of generations ago, man had thrust his brother man out of the ease and the sunshine. And now that brother was coming back changed... So, in the end, above ground you must have the Haves, pursuing pleasure and comfort and beauty, and below ground the Have-nots, the Workers getting continually adapted to the conditions of their labour... Such of them as were so constituted as to be miserable and rebellious would die; and, in the end, the balance being permanent, the survivors would become as well adapted to the conditions of underground life, and as happy in their way, as the Upper-world people were to theirs. As it seemed to me, the refined beauty and the etiolated pallor followed naturally enough. ...The too-perfect security of the Upper-worlders had led them to a slow movement of degeneration, to a general dwindling in size, strength, and intelligence. That I could see clearly enough already. What had happened to the Under-grounders I did not yet suspect; but from what I had seen of the Morlocks--that, by the by, was the name by which these creatures were called--I could imagine that the modification of the human type was even far more profound than among the "Eloi," the beautiful race that I already knew. (From The Time Machine [H.G. Wells, 1898])