Whatever process that created life on Earth... Is it still happening today?

Title says it all.

Basically what I’m asking is there still new life being created today? How would we know?

On your first question, it’s hard to say, because nobody knows for sure how it happened in the first place.

On your second question, biologists seem to be pretty good at identifying genetic relationships between different species. I am not a biologist, but I suppose one clue that a species might have come into being directly through abiogenesis would be if biologists couldn’t identify any relationships with extant species.

The big problem is that anything that’s vaguely sort of life-ish, is probably edible to some form of existing life. So any such process couldn’t get past the starting gate.

Oh, and we do know that all life that exists nowadays uses the same genetic code, even though there are a combinatorically-large number of possible genetic codes that would all work equally well (without even getting into the vague, difficult-to-quantify possibility of life based on some other genetic molecule than DNA). That’s extremely strong evidence that all life that exists now is related. It’s still possible that life arose multiple times, but if so, one of those lineages managed to drive all of the others to extinction.

I’m guessing this is the right answer. It probably does still happen but gets eaten pretty much instantly.

Agreed. And I’d bet it happens in thermal vents and areas with geysers.

My first interpretation of this post is: as soon as some new form of life is discovered, it is immediately eaten by the biologist, thus destroying the evidence.
Now I know that wasn’t what you meant at all.

This seems like it would work as an argument for the improbability of exotic species establishing themselves in new habitats. Something that has happened frequently.

The difference is that these invasive species have had a chance to evolve to be successful in their earlier environment, and these survival techniques may be well adapted for the new environment. Throwing spontaneously generated life into this arrangement is like throwing a new born baby into a ring with highly trained mixed martial arts fighters.

Even ignoring that, we don’t know how easy it is for ambiogenisis to kick off. It may be something that over the entire planet only happens one every billion years or so.

Another point is that Earth is a very different place than it was when abiogenesis took place. In particular, the primordial atmosphere had a completely different composition from the modern atmosphere. The air we breath today has been drastically altered by life itself.

IANAbiochemist, but I know enough chemistry to know that while we think of oxygen as wholesome and refreshing, it’s actually quite nasty stuff–we’re so used to it, we don’t even think about what a corrosive, destructive sort of element free molecular oxygen (O[sub]2[/sub]) really is; to us it’s normal that metals rust and things burst into flame, but billions of years ago that sort of thing just didn’t happen. In addition to the notion that any budding proto-life would be quickly eaten by some fully-living critter (shaped by 3 billion+ years of ruthless selection), our oxygen-rich environment may also be hostile to the sorts of chemical processes needed to spontaneously produce whatever complex molecules originally kicked off the cycle of reproduction and natural selection that eventually produced all the living things that now creep and crawl and swim and walk and fly all over our planet.

Short answer is no, it does not appear to be occurring. No, we don’t know why, we can only guess. We know that no other life is extant because of shared genetic code of all life as well as neutral similarities in genetic code. All life we have discovered has a single common ancestor. A single celled lifeform from about 3.5 billion years ago. One supposes it’s possible that some life we have not sequenced has arisen separately, but there is no evidence to suggest such.

This is the answer.

I have often wondered how many of the climate change deniers – especially the “it’s not us but rather a normal geologic event” apologists – are aware of the Oxygen Catastrophe. It triggered one of the great die-offs which ultimately lead to a much greater diversification of life (including us) but for the obligate anaerobes, not so much.

“Life as we know it” is ubiquitous on Earth. From the surface both up and down as far as we can sample, we find life and thus far, it’s all “as we know it.” The chirality alone is enough to support the “winner take all” version of why. Moderately convincing evidence on the chirality of molecular clouds very far away from earth seems to support the idea that even pre life chemistry went one way a long long time ago. Distance and everything being as vast as it is, there is enough room for sterile technique to apply to somewhere, but it is necessarily far away, for very large values of far.

Tris


Drakes equation predicts billions of planets with intelligent life. Current observations provide enough room to keep them millions of light years apart, and millions of years out of sync.

“New life” (nonliving matter forming a living system) is enormously more likely (essentially 100% certain in terms of probability) to be simple, because it’s the product of random events. So even if there were places where this can still happen, the problem is that new life is going to just get eaten by creatures with 3.5 billions years worth of sophisticated mechanisms.

We can absolutely model this and the numbers overwhelmingly show that this is what will happen, it’s not a guess. Also there are experiments that can be done in the lab with RNA strands that hint at what some of the early life was like.

My problem with this argument is the 3.5 billion years. It’s quite reasonable to say that one particular RNA-ish entity was eaten by competitors. It becomes much more difficult to believe that every single one of these proto-lifeforms for the past 3.5 billion years was eaten by more sophisticated life, especially given that we have some pretty simplistic life right now that seems to have survived. Prokaryotes emerged almost nearly as soon as life did and prokaryotes are still around today and manage to survive. If the process were still on-going, it becomes nearly unbelievable to think that something else couldn’t survive in 3.5 billion years. I think the ‘conditions have changed’ argument is stronger, but it has its own issues.

Your mistake there is in thinking that prokaryotes are “simple”. Try making one from scratch, and then come back and tell us how simple it is.

Right. Prokaryotes aren’t simple. They use DNA, they use ribosomes, countless intricate proteins and logic switches. The probability of a new prokaryote-class lifeform falling together by chance is so small it is not expected to happen even once in the lifetime of our universe, anywhere.

Prokaryotes aren’t thought to be the first life - the first life had to be much, much cruder. Current theories are something like a soap bubble of a membrane that formed spontaneously and some self-catalyzing chemistry but obviously this can’t be known with certainty. Even self-catalyzing RNA, which seems to be able to form into functional systems that can copy itself, is amazingly advanced compared to what the earliest life must have been.

Anyways, even if the conditions still exist somewhere on earth, such as near a geothermal vent, we already know that all the ecological niches near that vent seem to be choc full of a horde of advanced creatures with several billions years of refinements.