Sudden appearence? You think too highly of evolution.
As far as I know, T Preservans is a mutation.
And it's a piece of crap, really. :)
I could outprogram that even in the version it was designed for!
And I'm definately not a biologist. I think we should first understand how real cells do it. That, or just dive in, and say, "Forget how nature does it, this is just an Artificial Life Sim, not an actual perfect simulator!"
Unfortunately, we seem to be doing both, and yet neither. As far as I've seen, everyone except me wants it to be a really good simulation of life, but unfortunately, not many people seem to know much at all about how actual cells use enzymes, proteins, and all the other stuff they use.
This might be due to the fact that half of us are programmers, and the other half are biologists, or something on that level.
(I know only the basics of biology, but I'm a pretty darned good programmer. Go ahead and look at Duo Minimalis for proof; it's not as good as Deathgrip, or even DIN, but I take pride in how little energy it uses.)
I'd much prefer a simple system (well, simple in the way Assembly Language is simple) over a realistic one. :P