4 ms·

I understand what you meant. But here is the thing, nature did create some of the most efficient and marvelous engineering feats we have ever seen and still str

I understand what you meant. But here is the thing, nature did create some of the most efficient and marvelous engineering feats we have ever seen and still struggle to match. Take the knee for example. You would be really hard pressed to make something that has ALL the flexibility and functionality of the knee while being as durable and reliable even using some of the most advanced technology right now. Another example is the bacteria. Some bacteria is so efficient it is literally approaching the limit of thermodynamics. You would need some of the most overengineered heat engine to match that kind of efficiency. And I guarantee you that we are far from able to make such a system as small and reliable as a bacterium. In fact if such a system were to appear right now, we would immediately call it incomprehensible alien technology.

pama 3y ago
I work in related areas but have never heard of such bacteria. Typical evolution starts with barely workable designs and then lots of things get added on top to add robustness or efficiency. Bacterial engines and enzymes are very primitive compared to those in eukaryotic cells. Do you have any pointer to what you mean about their growth efficiency?
- tomohelix 3y ago
  Of course: Source: https://www.nature.com/articles/415454a https://www.nature.com/articles/415454a > Here we show that metabolism by syntrophic associations, in which the degradation of a substrate by one species is thermodynamically possible only through removal of the end product by another species1, can occur at values close to thermodynamic equilibrium (ΔG′ ≈ 0 kJ mol-1) Or this one: https://phys.org/news/2013-08-physicist-coli-replicate-thermodynamic-limits.html https://phys.org/news/2013-08-physicist-coli-replicate-therm... On the second link, you may think that 600% is quite bad but that is the lower estimate of a vastly simplified system. The author himself stated this: More significantly, these calculations also establish that the E. coli bacterium produces an amount of heat less than six times (220npep/42npep) as large as the absolute physical lower bound dictated by its growth rate, internal entropy production, and durability. In light of the fact that the bacterium is a complex sensor of its environment that can very effectively adapt itself to growth in a broad range of different environments, we should not be surprised that it is not perfectly optimized for any given one of them. Rather, it is remarkable that in a single environment, the organism can convert chemical energy into a new copy of itself so efficiently that if it were to produce even a quarter as much heat it would be pushing the limits of what is thermodynamically possible! This is especially the case since we deliberately underestimated the reverse reaction rate with our calculation of phyd, which does not account for the unlikelihood of spontaneously converting carbon dioxide back into oxygen. Thus, a more accurate estimate of the lower bound on β⟨Q⟩ in future may reveal E. coli to be an even more exceptionally well-adapted self-replicator than it currently seems. Basically, for the amount of redundancies and complexity of an entire bacterium, the 600% total estimate is quite impressive. And when you actually get down to the single reactions, you see that it is exactly at the limit of thermodynamics.
  - pama 3y ago
    Thanks. That 600% total estimate is much closer to what I expected. Don’t get me wrong. I admire bacteria but they are nowhere near as efficient as your initial comment suggested.
- ljlolel 3y ago
  Not at all, a bacteria today has evolved the same amount of time as us, billions of years. And has shorter reproductive span so has an immense amount of evolution built in to optimize it for not just myriad environments they are in today but also robustness to handle billions of years of changing environments. A bacterium of a billion years ago would not survive many niches if any. Anything alive today is incredibly complex and efficient in its ability to survive especially with so many eukaryotic and human predators.

pama 3y ago

I work in related areas but have never heard of such bacteria. Typical evolution starts with barely workable designs and then lots of things get added on top to add robustness or efficiency. Bacterial engines and enzymes are very primitive compared to those in eukaryotic cells. Do you have any pointer to what you mean about their growth efficiency?

tomohelix 3y ago
Of course: Source: https://www.nature.com/articles/415454a https://www.nature.com/articles/415454a > Here we show that metabolism by syntrophic associations, in which the degradation of a substrate by one species is thermodynamically possible only through removal of the end product by another species1, can occur at values close to thermodynamic equilibrium (ΔG′ ≈ 0 kJ mol-1) Or this one: https://phys.org/news/2013-08-physicist-coli-replicate-thermodynamic-limits.html https://phys.org/news/2013-08-physicist-coli-replicate-therm... On the second link, you may think that 600% is quite bad but that is the lower estimate of a vastly simplified system. The author himself stated this: More significantly, these calculations also establish that the E. coli bacterium produces an amount of heat less than six times (220npep/42npep) as large as the absolute physical lower bound dictated by its growth rate, internal entropy production, and durability. In light of the fact that the bacterium is a complex sensor of its environment that can very effectively adapt itself to growth in a broad range of different environments, we should not be surprised that it is not perfectly optimized for any given one of them. Rather, it is remarkable that in a single environment, the organism can convert chemical energy into a new copy of itself so efficiently that if it were to produce even a quarter as much heat it would be pushing the limits of what is thermodynamically possible! This is especially the case since we deliberately underestimated the reverse reaction rate with our calculation of phyd, which does not account for the unlikelihood of spontaneously converting carbon dioxide back into oxygen. Thus, a more accurate estimate of the lower bound on β⟨Q⟩ in future may reveal E. coli to be an even more exceptionally well-adapted self-replicator than it currently seems. Basically, for the amount of redundancies and complexity of an entire bacterium, the 600% total estimate is quite impressive. And when you actually get down to the single reactions, you see that it is exactly at the limit of thermodynamics.
- pama 3y ago
  Thanks. That 600% total estimate is much closer to what I expected. Don’t get me wrong. I admire bacteria but they are nowhere near as efficient as your initial comment suggested.
ljlolel 3y ago
Not at all, a bacteria today has evolved the same amount of time as us, billions of years. And has shorter reproductive span so has an immense amount of evolution built in to optimize it for not just myriad environments they are in today but also robustness to handle billions of years of changing environments. A bacterium of a billion years ago would not survive many niches if any. Anything alive today is incredibly complex and efficient in its ability to survive especially with so many eukaryotic and human predators.