Re: 2nd law clarifications

On 1/3/2025 6:24 AM, MarkE wrote:

On 3/01/2025 5:13 am, Ernest Major wrote:

On 02/01/2025 06:53, MarkE wrote:

Are these statements correct? Could they be better expressed?
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Local entropy can decrease in an open system with an input of free energy.
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Free energy alone is not sufficient to maintain or further decrease low local entropy: an energy capture and transformation mechanism is also needed.
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Extant life *maintains* low local entropy through its organisation and processes.
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Evolving life *decreases* low local entropy through the ratcheting mechanism natural selection acting on random mutations in instances where that evolution increases functional complexity and organisation.
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There is no other known mechanism apart from natural selection that does this. For example, neutral drift alone increases entropy.
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It is difficult to operationalise the concept of irreducible complexity, as that necessitates a principled definition of system, part and function. But if you pass over that point, there are at least three classes of paths (exaption, scaffolding, coevolution) whereby irreducibly complex systems can evolve. I suspect that the last is the most frequent, and that it can be driven by drift as well as by selection. If you are equating an increase in functional complexity and organisation with a decrease in entropy, then this would negate a claim that neutral drift always increases entropy.
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 What I would say more confidently is, "For example, neutral drift alone increases disorder."
 More precisely, if a population fixes neutral and near-neutral mutations over time through drift, with no selection acting, the net effect over time will be devolution, i.e. a loss of information and functional complexity. The end state will be extinction.
 Does this necessarily mean entropy will increase? It would seem so.
 

It would be non neutral drift that would likely be associated with increased disorder.  Even if something is selected against it can still be fixed in a small population by factors not directly affecting the trait under selection.  90% of a population might be wiped out by some disease and the survivors may just, by chance, have a high frequency of some deleterious allele that might get fixed by random chance.
Neutral drift is just neutral changes, it shouldn't result in any increase in disorder because those changes are selected against.  Look at the coelacanth it has been adapted to a specific environment for hundreds of millions of years, and has changed very little, and yet genetic drift in their DNA sequence and physical features invisible to the environment have changed, but the outward physical appearance has not degenerated.  Drift has occurred even as the morphology has been maintained.  The skull may make nearly identical fossil impressions, but when you look at the skull you observe that all the bones that make up the skull have very different sizes and shapes, but still make the same overall skull shape.  This is neutral drift.
Drift can result in loss of gene functions that are no longer needed in certain environments.  The eyes in cave fish are an example, and even that isn't neutral drift because the loss of eye function has selective advantage because of the energy consumption of tissue that is no longer needed.  Pigmentation loss in caves may be a better example, but watching the nature shows and observing all the deep sea fish that retain their eyes and bright colorations make me think twice about it.
Ron Okimoto