That is, what sustains today’s life prevents new proto-life for forming. You need to have the fancy gadgets life has today to continue to survive and replicate on Earth.
Note though, it was other life forms that contributed to the great oxygenation event, too. This is all a continuous web.
Do you think complex life could develop (perhaps by moving backwards) in a way that they rely on an anaerobic metal-rich environment?
I guess the oxidation event maybe was necessary for life to develop enzymes (since there wasn't sufficient evolutionary advantage for it to develop in an anaerobic environment?) but maybe something could go backwards? I'm just curious if there might be advantages for live in that sort of environment.
> Just curious, are there lifeforms today that rely on these metals to live in anaerobic environments? Maybe the hydrothermal vents that are talked about?
There are actually quite a few environments on Earth that are time capsules / have little ship bottles of very different life inside of them. For example, the Movile cave, https://en.wikipedia.org/wiki/Movile_Cave
Life in the cave has been separated from the outside for the past 5.5 million years and it is based completely on chemosynthesis. Due to its extreme environment, access to Movile Cave is strictly controlled, and a limited number of researchers have permission to study its conditions.
[1] https://en.wikipedia.org/wiki/Dissimilatory_metal-reducing_m...
[2] https://en.wikipedia.org/wiki/Sulfate-reducing_microorganism
What proto life did, it seems, was completely depend on metal surfaces to speed up some reactions. But that’s messy. The same metal can’t distinguish different components, so there would be competition for these surfaces, even within the same “cell”. That’s not ideal.
Enzymes are much more specific. You can actually sequester different reactions. And once you have life that’s learned to do that, it will out compete any proto life like matter that may access such environments.
Anaerobic microbes have enzymes also. So don’t think that reducing conditions mean no enzymes. It’s merely that in reduced conditions, you have metal that’s not oxidized available for early life -like goo to make use of. Over time, once this life learns to make newer and newer enzymes, the need to be metal dependent went away.
Somewhat separately, you also had some of this lineage learn to photosynthesize, and that lead to bulk oxygen in the atmosphere, and that was initially catastrophic, then highly beneficial because oxygen based chemistry is way more energetic than anaerobic chemistry.
It would be wrong to think of either condition as “better” though. They’re different. They force different tradeoffs. And both demand fine balance and dependence on the environment, eventually.
The surfaces of clay particles in these lakes have been dubbed "the primordial sandwich".
The early protocells were 'alive', they were self-replicating, but they required nutrients and metabolic processes that only existed near mineral surfaces and would starve if they drifted away. They had to evolve new enzymes to become 'free-living'.
So it looks like the LUCA was one of these early protocells with an incomplete metabolism.
It's possible OoL requires some exponentially unlikely step. We wouldn't realize that because of observer selection: had the step not occurred, we wouldn't be here to be thinking about it. There's a huge complexity gap between the stuff produced in OoL experiments and the simplest known life.
It's also possible OoL requires conditions that no longer exist on Earth, or that only existed in the early Earth (or wherever life got started in the Solar System). For example, if it depended on the existence of short lived radioactive isotopes or free ammonia.
Indeed, all species branch out from that one universal common ancestor that was the first free living successful cell.
Put another way: forming life isn’t easy at all. And once it forms it changes conditions to suit its continuation, not to allow new life to form.
Probably this. How would we know what such 'proto-life' (perhaps even just some self-replicating soup of chemicals, no cell wall) would look like? Where to find it? How rare its occurence? Etc etc.
Scientists might not even recognise it if happened right in front of them.
I'd put my money on coming up with a more general definition of "life", and then looking for short(est) pathways from "soup of random chemicals" to "something in there that replicates (parts of) itself".
Doesn't need to look like life as we know it, as long as some elements of "self-organising structures, something being replicated" are there.
And life may have arisen from a very low probability set of circumstances ... there's no reason to expect it to be happening all the time.
The fact that it doesn't is a pretty simple solution to the Fermi Paradox.
Anything that's so agreeable to abiogenesis that life might spontaneously manifest, is actually pretty tasty for things already alive. They swoop in and eat it before it gets started. So, I suspect that even what the article says isn't that they both arose in the same place, but in different places separated by distance, time, and/or environmental barriers.