[snarks_when_bored]

I'll guess 1.2 trillion

At least, DS. I think of it this way (perhaps you have a better way). Life has been around about 3.5 billion years, so if organisms on average lived for a year, that would be 3.5 billion generations. But, of course, for almost 3 billion years, only microbial life existed here, and microbes live only about a half hour or so. Let's say an hour, to be generous. Then, considering microbial generations, we have to multiply 3.5 billion by 365 and multiply the resulting product by 24, no, let's say by 15, since the day was shorter billions of years ago. So we get well over 19 trillion generations of microbes.

Now imagine each genome of each microbe trying to faithfully reproduce itself over 19 trillion generations through asteroid hits, comet hits, vulcanism on a colossal scale, changes in the atmospheric gas composition, cosmic ray bombardment, etc., etc. Not going to happen. And we mustn't forget that in, say, a gram of soil, there are something like 10 million microbes. So not only is the number of generations astronomical, so, too, is the number of individuals reproducing.

Holy cow. What might be produced from such a process? (Where's my mirror?)

[snarks_when_bored]

That last post was written quickly. I should've upped the number of days in the year, since I dropped the average number of hours in the day. But we're within an order of magnitude, so it ought to suffice.

[PatrickHenry]

... well over 19 trillion generations of microbes.

Your error is that you've ignored the Flood. You have only a few thousand years to work with.
</creationism mode>

[VadeRetro]

Then, considering microbial generations, we have to multiply 3.5 billion by 365 and multiply the resulting product by 24, no, let's say by 15, since the day was shorter billions of years ago.

If you aren't going to put more days in the year (the Earth's orbit around the Sun being about the same), you might as well leave it at 24-hour days.