In reply to Timmd:
> Fair point about belief in the existence of souls being religious, or one of faith, but I don't know how you'd know to guess he'd say souls were put into humans relatively recently?
It is the standard Catholic position, as enunciated by JP2 and Pius XII. Under Catholic theology, animals evolved as in the usual scheme. But, at some point, God took two "animals" and turned them into humans by putting souls into them. Those two, Adam and Eve, were the first humans.
" if the origin of the human body comes through living matter which existed previously, the spiritual soul is created directly by God ..."
"With man, we find ourselves facing a different ontological order—an ontological leap, we could say."
http://www.ewtn.com/library/PAPALDOC/JP961022.HTM
Also:
"Pope Pius XII stated: "When, however, there is question of another conjectural opinion, namely polygenism, the children of the Church by no means enjoy such liberty. For the faithful cannot embrace that opinion which maintains either that after Adam there existed on this earth true men who did not take their origin through natural generation from him as from the first parents of all, or that Adam represents a certain number of first parents."
http://www.catholic.com/tracts/adam-eve-and-evolution
Admittedly, Francis might disagree and update Catholic theology, but so far he has not done so. His recent statements are entirely in line with JP2.