Certain Personal Matters by H.G. Wells — Read

It is part of the excessive egotism of the human animal that the bare idea of its extinction seems incredible to it. "A world without _us_! " it says, as a heady young Cephalaspis might have said it in the old Silurian sea. But since the Cephalaspis and the Coccosteus many a fine animal has increased and multiplied upon the earth, lorded it over land or sea without a rival, and passed at last into the night. Surely it is not so unreasonable to ask why man should be an exception to the rule. From the scientific standpoint at least any reason for such exception is hard to find.

No doubt man is undisputed master at the present time -- at least of most of the land surface; but so it has been before with other animals. Let us consider what light geology has to throw upon this. The great land and sea reptiles of the Mesozoic period, for instance, seem to have been as secure as humanity is now in their pre-eminence. But they passed away and left no descendants when the new orders of the mammals emerged from their obscurity. So, too, the huge Titanotheria of the American continent, and all the powerful mammals of Pleistocene South America, the sabre-toothed lion, for instance, and the Machrauchenia suddenly came to a finish when they were still almost at the zenith of their rule.