In Part 4. of this series (which starts here), I discussed two key ideas: 1. How to get from small stuff (like atoms) to big stuff (like stars and planets), and 2. How this process ultimately yields atoms that are themselves larger and more complex. Here is a table of those atoms (elements):
Elements of course allow chemical properties to emerge. How that emergence fits in with my Model of Everything (thus far) is shown below:
So, to continue building the model, then, it’s necessary to introduce a fantastically-important and not-as-yet-understood process within chemistry–a process that has occurred at least once in our past: abiogenesis.
Abiogenesis is a scary-looking word that simply means getting from the stuff of non-life to the stuff of life–a big step to be sure–and one that represents another level of emergence in my model. In short, it seems that the chemistry responsible for molecules like H2O and amino acids also can yield a molecule that copies. And THAT is a special molecule indeed.
This self-copying, self-replicating molecule is what life needs to get going, and whatever the original variant of this molecule looked like, it was almost certainly different than the replicators central to life today–molecules like RNA and DNA. The originator of replication would have been a simpler version of these and may have gotten its start piggy-backing on shapes constructed by inorganic compounds–such as the crystal lattice of minerals. Repeating crystalline structures are not living things (in any sense we think of), but if naturally-occurring organic molecules hitched a ride on just the right template, one with a particular connectivity, an arrangement that allowed the already-repeating pattern to be picked up by an organic molecule–well that’s just the sort of thing a planet replete with organic compounds can work into something special.
Here’s a molecule making copies now:
And look, it made a “mistake” on copy B–there’s a circle shape where the original had a line:
I can hardly overstate the importance of such infidelity, such faithlessness to the original. This trait is crucial to yielding complexity and “improvement”. Without infidelity we would not be here today (perhaps for some of us in more ways than one). Without infidelity there can be no variation, and without variation, no single copy of “A” will ever be better at making copies than any other.
As a quick aside, I find it interesting that most world religions see our straying from the “straight” and “faithful” path as “sin”, but our natural inability to be “true” is the formula of our success. Imperfection is the engine of creativity; it is the “soul” of life. But let us not push our metaphors too far (at least not yet). The point of this post is really just to get to something like these:
Now maybe they aren’t the most complex examples of life, but our interest is not in complexity–it’s in existence. This property of chemistry is almost too-wonderful, intriguing, amazing–the idea that atoms, if brought together in just the right way, will yield a molecule that copies.