3 ms·

> For it to count as “environment” the organism must be able to survive for at least a time without it. How long can a cell survive without liquid water? It li

> For it to count as “environment” the organism must be able to survive for at least a time without it. How long can a cell survive without liquid water? It literally enables almost all of the chemistry inside the cell. Cell requiring a specific metal to be present is not very different from cell requiring for liquid water to be present. Initially life started in favorable conditions, then spread to less favorable ones. Lack of metal catalyst around was the initial less favorable condition. At some point lack of liquid water was one. But eventually life spread to various very dry or cold places because it found workarounds for environment infeasibilities. Maybe in 5 billion years life that can't survive without liquid water around and can't substitute it with self-made polar solvents and thus is stuck to surfaces of very few, very particular planets is going to be considered proto-life.

randomImmigrant 2mo ago
>How long can a cell survive without liquid water? Depends on the cell, but it’s not instant death. By definition, a cell is a membrane with some water inside it. Sure, move that cell to totally dry conditions and most will die. But not all, by any means. Bacterial endospores last millenia without water. Tardigrades can do years. This isn’t quite the gotcha you think it is. The metal use for multiple catalytic steps is distinct. The paper isn’t wrong about that at all. Trying to prove the closed loop metabolism of modern life is secretly open loop isn’t going to work because it isn’t open like that. An organism can survive without constant contact with any of its components. Sometimes not for very long, but nothing alive today is as dependent on something external as these proto cells were on reduced metal.