Joined: Jan. 2007
Glad I found this thread.
OOL research is a fascinating topic area for me.
I think there are numerous directions from which to approach it that could offer incite. Incite might be our best we can hope for in the short term since we do lack the exact details of the primary chemistries on the early earth. Fortunately, incite can offer great directionality to further inquiry if that incite stimulates curiosity to the point of goading a researcher into following a line of inquiry long enough for it to bear fruit.
In considering OOL, since we are dealing with unknown processes and conditions, we are essentially working in the abstract. We are basically attempting to ferret out the nature of the pre-cellular material processing. When we talk of specifics - what reaction kinetics are necessary for a specific molecular species to predominate in a solution, for instance - we need expert knowledge of chemistry. However, at this point, even the chemistry experts are looking for a guide in the form of a plausibility argument for how the transition to cellular life occurred. In this process of creative guessing, anyone with the ability to combine the basic capabilities of chemical species - get longer, get shorter, fold, match shapes, make reactions easier, make reactions harder, prefer reacting with some other chemicals, be stable, be unstable, among others - in, perhaps uncharacteristic, tinker toy kinds of ways, potentially has the ability to offer incite into the origin of life. So, to those of you who have prefaced your posts with self-deprecating comments about your understanding of chemistry or the current state of OOL research I say start looking at it in a more creative, more abstract way. The current state of OOL research is more about looking for a way to proceed than it is about discovering the answer. Realistically, the spark that illuminates the most promising path forward may well be ignited by observing soap bubbles or watching a kite line entangled in a tree.
The sciences like chemistry and physics have demonstrated for us that the chemistry of living things is not distinct from the chemistry of non-living things. This provides us with all the reason we need to pursue the earthly - as opposed to pre-existing life riding to earth on a comet - origin of life as a legitimate discipline with hope of success. That progress toward the goal of understanding the OOL on this planet might be slow can be understood and accepted when we consider how ill-prepared we still are, even in the scientific community, to deal with the level of complexity associated with living things. When I say complexity, I simply mean the capacity to simultaneously account for the behavior of a large number interacting entities.
The difficulty of predicting behaviors becomes apparent when we look at three-atom water, for instance. Water is composed of one oxygen bonded to two hydrogen atoms. The characteristics of water are "emergent" properties of the combining of those three atoms in that exact way. The properties of molecular water are very different from those of molecular hydrogen, very different from those of molecular oxygen, and very different from any mixture of the two. Then, too, the specific configurations of the atomic species in water itself make for still different emergent properties of water as a gas, as a liquid or as a solid.
Just as water is an emergent property of oxygen combined with hydrogen in exact proportions under specific conditions, life, too, is a product of emergence - emergence at many levels. At the atomic level, life depends on the emergent properties of sodium and calcium ions interacting with water. At the molecular level life depends on characteristics of water, amino acids, nucleic acids, and glucose to name a few. At the macromolecular level lipids, DNA, RNA, and proteins for instance, all exhibit properties quite distinct from their component sub units. Emergence continues through the sub-cellular, organelle, cellular, organ, organ system, organism, society, and ecosystem levels.
To me, this is a fascinating topic and I hope others find it as engaging as I do.
For the purposes of discussion, here, what do we consider life? Are self-replicating molecular species alive? Is a cell wall required? Can any series of reactions be considered living if they are not enclosed in a cell wall but still result in the production of a specific molecule? Are we looking for literal inheritability in that a "parent" creates a duplicate "daughter" genetic molecule and passes it to its progeny? Is a microsphere alive if it reproduces simply by swelling and breaking in half?
Which comes first metabolism or inheritability? Can they be the same thing?