The sine qua non
of life is a flow of energy with negative entropy. The current major source is the solar energy/entropy/information from the Sun, but a possible source for the original macromolecules of life are the deep-sea vents of residual cooling energy (or radioactive decay energy) at the bottom of the seas.
In either case, the far-from-equilibrium energy flow is essentially a thermodynamic engine, running between the hot energy source of the Sun and the cool sink of the night sky as the earth rotates. Energy flows lead to material flows in gases and liquids that produce dynamic systems with semi-permanent visible structures like convection cells.
At some moment, a primitive macromolecule replicated itself. To do this, it created new (duplicate) information, so positive entropy equal to or greater than the new negative entropy must have been carried away from the new information structure (for it to be stable).
Mere replication should not yet be seen as life. And anything like metabolism would just be the flow of the low entropy solar photons that get degraded in the process of providing the available energy needed to form the new molecule. But we might anthropomorphize a bit and say that the apparent
purpose of the molecule appears to be replicating itself, increasing its own kind of information structure in the universe.
Now at some point the replication might have been less than perfect (note the critical element of chance
Imagine now that the new molecule might be even more efficient than the original molecule at replicating itself (it has greater reproductive success). Note that the new molecule has more information in it than the original. Now we might say that this is the beginning of Darwinian evolution, which appears
to have a goal or purpose of building richer information structures.
We now have both primitive inheritance (of the information) and a form of variability. Some of these new molecules might not only be more successful replicators, they might have chemical properties that allow them to resist being destroyed by environmental conditions - the energetic extreme ultraviolet photons, for example, or destructive cosmic rays, which might have been the source of the original variations.
The result might be a runaway exponential explosion of the concentration of those molecules (an important characteristic of living systems).
Replication could lead to populations of the molecule that are well beyond the normal populations that would be expected in chemical equilibrium. Chemists might view this as simply an autocatalytic process, in which the molecule catalyzes its own production. But because it is information replicating itself, it is qualitatively different from mere chemical autocatalysis.
At the atomic level, it will be quantum cooperative phenomena that pull the constituent atoms into the desired molecular shape. It is the overall shape (form, information) that produces a dynamical constraint well beyond the mere aggregate of individual atoms interacting.
Grossly speaking, the new, more successful species of molecule have "learned" something, storing the new information internally to pass it on to the next generation.
Origin of Life Links