> it sounds unlikely that a) there really was that single origin cell, and not a few that popped up around the same time (on a geological scale) Why? Life hap

> it sounds unlikely that a) there really was that single origin cell, and not a few that popped up around the same time (on a geological scale) Why? Life happens rarely enough; even in the 'optimal' conditions of the primordial soup, it's still a pretty miraculous occurrence for a cell to spontaneously form. Then consider this: - The first cell was probably not 'good' at surviving, even in those conditions. It probably sucked at it, and was just barely good enough at doing it to reproduce a little and evolve a little. - So, a cell which is actually good at surviving is pretty much guaranteed not to form spontaneously. Meanwhile, the lineage of the first (shitty) one has evolved to be pretty damn good at it. - If a new cell tries to form, even if it's better at surviving than the Original cell, it'll probably get instantly outcompeted by its progeny. Voila, single ancestor cell. > b) no organism has drifted in the millions of years of evolution. Why should they? There's no pressure to.