I am reading The Selfish Gene by Richard Dawkins.
I am on chapter two.
He speaks of the observation of the formation of amino-acids when you simulate environmental conditions of primordial earth.
UV light + water + carbon dioxide + methane + ammonia + a couple of weeks time = amino-acids
I understand that amino acids are an organic compound that serve a lot of important functions in our bodies.
Presumably, they are important to all life, because from the context I can derive, they seem to be somewhat of a precursor to life itself.
Dawkins then says:
Processes analogous to these must have given rise to the 'primeval soup' which biologists and chemists believe constituted the seas some three to four thousand million years ago.
He goes on and eventually states:
At some point a particularly remarkable molecule was formed by accident. We will call it the Replicator. ....
Actually a molecule that makes copies of itself is not as difficult to imagine as it seems at first, and it only had to arise once. Think of the replicator as a mould or template. Imagine it as a large molecule consisting of a complex chain of various sorts of building block molecules. The small building blocks were abundantly available in the soup surrounding the replicator. Now suppose that each building block has an affinity for its own kind. Then whenever a building block from out in the soup lands up next to a part of the replicator for which it has an affinity, it will tend to stick there. The building blocks that attach themselves in this way will automatically be arranged in a sequence that mimics that of the replicator itself. It is easy then to think of them joining up to form a stable chain just as in the formation of the original replicator. This process could continue as a progressive stacking up, layer upon layer. This is how crystals are formed. On the other hand, the two chains might split apart, in which case we have two replicators, each of which can go on to make further copies.
A more complex possibility is that each building block has affinity not for its own kind, but reciprocally for one particular other kind.
Then the replicator would act as a template not for an identical copy, but for a kind of 'negative', which would in its turn re-make an exact copy of the original positive. For our purposes it does not matter whether the original replication process was positive-negative or positive-positive, though it is worth remarking that the modem equivalents of the first replicator, the DNA molecules, use positive- negative replication. What does matter is that suddenly a new kind of 'stability' came into the world. Previously it is probable that no particular kind of complex molecule was very abundant in the soup, because each was dependent on building blocks happening to fall by luck into a particular stable configuration. As soon as the replicator was born it must have spread its copies rapidly throughout the seas, until the smaller building block molecules became a scarce resource, and other larger molecules were formed more and more rarely.
As someone with a limited understanding of Biology and Chemistry, I have a couple of questions.
We have observed that the chemical conditions outlined at the top of this question seem to yield more complex organic compounds with time. Do we know (or have theories) as to why this is, or is it merely something we have observed and re-created?
The theory about replicators suggests that they are like a chain of building-block molecules each with an affinity for either its own kind, or some other kind. (positive-positive vs positive-negative). -- Which ever was the case, you could end up with a big chain of molecules that had a fractal nature, because these building blocks were freely available in the soup surrounding the replicator. -- If the chain split apart, you would get two identical copies and each part could go off and replicate further.
Now, I suppose this question mirrors the first, but why is it that it is so easy to imagine the affinity relationship? What makes molecules want to stick together with other, specific molecules?
Further more, what makes chains of molecules split apart (replicate)?
Can somebody elaborate further on these points, and on what Dawkins is saying here in general, so as to pander to the cravings of someone who is not particularly versed in the parlance?