Re:First Support for a Physics Theory of Life
by saalweachter on Wednesday July 26, 2017 @10:13PM
(#14862150)
I was going to post something similar to xenadu02's, but logged back on to find his post already there, so let me tackle a different point.
The simplest bacteria today are amazing organisms. They have cell membranes, which separate the protoplasm of the cell from the outside the world, and only selectively let some molecules through. They contain a blueprint to produce catalysts for a variety of chemical pathways; they can store energy in chemical form and use that energy to catalyze these reactions. The can break down complex molecules into simpler molecules and reuse these building blocks for their own purpose. They can move, to seek out new food sources. They can produce toxins that interfere with the chemical pathways of other cells, killing them.
But when we talk about abiogenesis, we aren't talking about the spontaneous generation of a cell. We're talking about the spontaneous generation of a single molecule, or a small set of molecules, probably proteins (amino acid chains) that, in the presence of proper raw material (amino acids) will tend to act as a catalyst for the formation of more of itself.
That's it; the reaction does not even have to be fast or obvious, even. If it takes years for the molecule to catalyze its replication, that's fine. Everything on top of that comes down to evolution, the slow development of a new trait - cell ways, a genome separate from the cell machinery, the ability to metabolize organic molecules into raw materials, locomotion - over millions of years.
So in addition to xenadu's point, there's also this: the abiogenesis of new self-replicating molecules could still be happening today, and we'd probably never know. The objects in question are too small, and the time scales involved are too large.
The simplest bacteria today are amazing organisms. They have cell membranes, which separate the protoplasm of the cell from the outside the world, and only selectively let some molecules through. They contain a blueprint to produce catalysts for a variety of chemical pathways; they can store energy in chemical form and use that energy to catalyze these reactions. The can break down complex molecules into simpler molecules and reuse these building blocks for their own purpose. They can move, to seek out new food sources. They can produce toxins that interfere with the chemical pathways of other cells, killing them.
But when we talk about abiogenesis, we aren't talking about the spontaneous generation of a cell. We're talking about the spontaneous generation of a single molecule, or a small set of molecules, probably proteins (amino acid chains) that, in the presence of proper raw material (amino acids) will tend to act as a catalyst for the formation of more of itself.
That's it; the reaction does not even have to be fast or obvious, even. If it takes years for the molecule to catalyze its replication, that's fine. Everything on top of that comes down to evolution, the slow development of a new trait - cell ways, a genome separate from the cell machinery, the ability to metabolize organic molecules into raw materials, locomotion - over millions of years.
So in addition to xenadu's point, there's also this: the abiogenesis of new self-replicating molecules could still be happening today, and we'd probably never know. The objects in question are too small, and the time scales involved are too large.