No, they say it because population geneticists do not have a problem with it. Also because we have good evidence now that the earliest eukarayotes developed in a form of communal coming togehter of once free living bacteria - mitochondria and chloroplasts, and even some ciliate structures, show this clear signature.<quoted text>
Last time I checked, it was over 50,000! But never mind the lab work - what about the number of "theoretical" generatons since the "time" bacteria first "evolved"?
How could any "sane" evolutionist believe that bacteria could ever evolve into anything other than bacteria? They will just say it did because that's what the theory says and that's a fact and it can never be demonstrated or observed but still it happened because its a fact and we say so.