Evolution and Christianity and Salvation

[Yonadav]

i raised this issue on a Catholic forum recently and I was surprised how little it bothered people.  I claim that Catholicism and Evolution are not compatible, based on the following: 

Consider that it is a fundamental tenant of Christianity that ALL human beings, every one alive today, MUST trace their linage back to a single man (or woman) that committed the grave sin of rejecting God.  If you think this was Adam and Eve in the Garden of Eden, fine - you don't believe in Evolution and you can downgrade to other discussions on the topic. However, the general consensus of science-based Christians (including Cardinal Ratzinger) is that, if you want to rationalize evolution with Christian dogma, you must assume that ONE human being (and only one), at some time in our past, was 'injected' with a soul.  This was the first human being with a soul, perhaps 50,000 years ago (or 6,000 who knows).  This soul-endowed human then rejected God in some manner, committing the first sin, and henceforth all his progeny carry that burden forward throughout all of history.  Hence the need for salvation, and Jesus and the Resurrection, and so forth.  I have talked with many Catholics on this and this is not in dispute.  This is how you rationalize evolution with Christian dogma.

So...here was my point:   If you subscribe to the above Christian rationalization of Christianity, you MUST accept the following:

1) There was a large population of "soulless" people
2) The one person with a soul had parents that had no souls, and perhaps siblings with no souls
3) The one person lived in a world filled with contemporary people that had no souls
4) All genetic lines EXCEPT the one with the souled person died out, so for generations, many people continued to live and be born as human beings without souls until their lines all died.

The above is not my opinion.  This is what you MUST believe if you rationalize Christianity and Evolution.  This is foundation, and the essence of salvation.
Am I missing something?  In many ways I respect those that are Creationists, as at least that position is logically consistent.

One thing that has bothered me with religion is not so much that it can be false, but what you MUST accept if it were true.

Understood in that particular way, then all of the lines without souls did not have to die out; they merely have to have mixed with the line that has souls. The only way that it would be possible for any line to not have souls after many generations would be for a line originating from someone with no soul to exclusively mate with others with no soul for generation after generation. As lines with no soul become less and less common, the chances of a member of a line with no soul mating with the member of another line with no soul becomes less and less likely.