All the story so far has been 'random events' or 'Proteins From Spaaaace!'. We move to Evolution which is a zillion times faster than random chance. Tell your kiddies that we compress millions of years into the space of a comma.
The main point so far is that we needed some Moly to eat. You can't chop wood with wood. Molies controlled the formation of life, and there may have been times of more or less Molies in the world. The physics of evolution isn't your bbc mushy mushy story by that old guy. It is ruthless, and involves the tiniest change of atomic electron force on a protein. The winners do a happy dance, and losers become sediment.
Moly has a happy home and she wants to have kids. Evolution requires an exact copying method (99%), with some room for error. All her kids will be Moly clones with one weird one. That little guy will either go on to great things or get eaten. Kids can cover their eyes for this one.
We must get an enzyme to reproduce without the whole DNA thing, and it is simple. Just have the RNA peel-off facial mask thing all by itself. Moly's enzyme home just turns to a straight stick, instead of a rolled mess, and attracts a new set of building blocks. Then peel it off, and, voila! a perfect copy, except for one thing. It needs to suck in more Moly, batteries are not included. Chicken and Egg.
Soon, the vent has lots of Moly-babies eating everything in sight. They become bigger, and don't split right away. The easiest formation is a flat shield with a slight curve. This forms a big sphere (relative) to the Moly, and Let the Evolution Games Proceed, with bacteria.
--End--