Did Life Emerge In Ponds Rather Than Ocean Vents? 97
ananyo writes "The prevailing scientific view holds that life began in hydrothermal vents in the deep sea. But a controversial study (abstract) suggests that inland pools of condensed and cooled geothermal vapor have the ideal characteristics for the origin of life. The study hinges on the observation that the composition of the cytoplasm of modern cells is very different to that of seawater. On the other hand, the mix of metal ions in cytoplasm is (almost exclusively) found where where hot hydrothermal fluid brings the ions to the surface — places such as geysers and mud pots. There are a number of problems with the study, however — for instance, a lack of land 4 billion years ago would have made it difficult for life to start in such pools."
Prevailing View? (Score:5, Interesting)
This is actually a bit surprising to me. Years ago, which admittedly was the last time I payed any attention to such things, the theory that life first formed in little pools was the common explanation. Up near the surface is where a lot of the energy was from sources such as the sun, volcanos, lightning, etc. I could be wrong in remembering this, but the primordial soup was always depicted as fairly shallow pools (though, perhaps, saltwater tide pools).
Re:Interesting. (Score:5, Interesting)
Does this mean that life on exoplanets without deep seas and hydrothermal vents is still possible?
Perhaps a more arid world, where water isn't quite as common as on Earth.
I'm interested to see what implications this has for the search for life. It could expand the possible amount of planets that are likely to evolve life.
Sure. So far we (seem) to have only one data point for conditions that allow for biological activity. We can postulate many others but until we get probes on Mars, Arcturus and other heavenly bodies, it's just a guess.
As, of course, is TFA. Interesting theory - that current ion concentrations within the cell more or less faithfully represent the ion concentrations of some ancient ancestor due to the inherent conservation bias found in living organisms (if it works, it works, keep it around). The big problem with that idea, IMHO, is that it can just as easily be postulated that very early life was unable to keep ion gradients within the cell (because they did not have an established, complicated cell membrane) but didn't need to because, well, because they were barely conscious pond scum and didn't need the ion gradient (or whatever) found inside modern cells because they were dumb and primitive and did nothing besides make a couple more copies of themselves. Perhaps the folding and unfolding of the primitive nucleic acid (likely RNA or something similar [wikipedia.org] to it) was more tolerant to ion fluxes than the complicated machinery we have now.
Interesting however. Much better than the typical PR piece.
Thus, they may have evolved anywhere where conditions were favorable for the primordial pond scum, be it hydrothermal vents or whatnot.
Re:Prevailing View? (Score:5, Interesting)
There are, as usual, competing ideas. Ever since hydrothermal vents were discovered to be full of living things in supposedly inhospitable conditions (which really isn't true, there is plenty of life in an abyssal plain surrounding a hydrothermal vent, it just isn't as photogenic as it's glopping around in the mud) it has been thought that perhaps these structures were candidates for nurturing very early life forms. Such vents were likely to occur as soon as water precipitated. So you have water (of some unknown ionic concentration, likely fairly anoxic), dissolved metal ions, dissolved bits of clay (both useful as a catalysts) and energy. Next thing you know kids are texting and doing drugs....
I could wave my flippers and postulate that there were micro environments in the vents that were also ion rich but that's just speculation ...
Huh? (Score:5, Interesting)
Why is this idea that life happened *once*? Precursor reactions invariably happened many times all over the place. Who knows how many time it almost began and didn't quite make it, or began and got wiped out. Eventually, obviously, it happened and life fanned out from there. But I'm guessing it happened all over the place and not just one time in one place. The odds would seem to be against that.
Re:My grandpa wasn't a monkey, or pond scum! (Score:4, Interesting)
3 scientific degrees from Ivy league universities, and a job at NASA doesn't mean you're batshitproof, alas.