It’s surprising because they would be the only organisms on Earth to do this. There are many metabolic processes that go in the forward direction and the reverse direction. That is something that life uses quite a bit just to be more efficient with our enzymes. But the idea that your respiration — what you breathe, what you get energy from — that you could, under different circumstances, get energy from running that reaction in reverse, that’s much more controversial.
The reason this is not fully accepted is that it is really hard to study. It’s hard to study things within the thermodynamic edge. It’s hard to be really certain that you have a pure culture.
How about the microbes that may live for thousands or millions of years? What do you know about those?
This is another inference, but all evidence points to the fact that a lot of these organisms just don’t experience enough energy at a rate fast enough to ever appreciably undergo cell division. Which is a little weird when you think about bacteria. The ones that make us sick grow fast. But the ones in the subsurface, deeply buried in places where not much happens, can’t [grow fast]. And so the implication of that is that individual cells can be alive for thousands of years, tens of thousands of years, maybe hundreds of thousands of years, without ever making a new cell. Just repairing broken parts, metabolizing, sending out conversational molecules to talk with their neighbors. Doing ecology, but not making a new cell and then dying.
You have to say, well, how do you evolve for that? We know that you can evolve to be dormant for a season because waiting a few months for the sun to come back to get energy, for plants, and food, for everybody else — that makes sense. But that is easy to think about because our lives are long enough to span that time.
Source link
