The Bible seems to take for granted that there were other humans in the world at the time Adam and Eve were created. Cain, after all, is said to have "built the world's first city." Their third son is Seth, who is the actual progenitor (with Abel dead and Cain banished).

Adam and Eve appear in Chapter 2 of Genesis. The creation narrative in Chapter 1 ends with the creation of humans: "man and woman."

I have often wondered whether we have there a cultural echo, passed down through the millennia, of a time when Homo sapiens and Homo erectus (in the form of Neanderthals, Denisovans, etc.) were living in proximity to one another--and interbreeding, especially sapiens males with erectus females. That would make Adam and Eve the first Homo sapiens--and allow their creation to explain the profound difference between erectus and sapiens: the latter were the result of an intervention by God in the world; the former were the product of the evolutionary process God put in motion with the Big Bang (which should really be called the Phenomenal Flash, given that no medium existed to transmit sound). "Let there be light," eh?