Conditions for Abiogenesis

[troodon]

Life formed naturally ~4 billion years ago on this planet, this thread assumes this (hence why it's not in the Cre-Evo Forum. Creationists need not apply.). Do the conditions for abiogenesis still exist or did they cease to exist at some point in the intervening 4 billion years?

Do you think it likely that life, or something approximating life, has been created additional times in that period? If so what happened to it? Would life from our own lineage destroy it almost immediately? Could it still exist as some sort of extremophile? Would we even be able to recognize such an organism/protoorgamism as being derived from a separate abiogenesis event?

 

[Chesterton]

Life formed naturally ~4 billion years ago on this planet, this thread assumes this (hence why it's not in the Cre-Evo Forum. Creationists need not apply.). Do the conditions for abiogenesis still exist or did they cease to exist at some point in the intervening 4 billion years?

Do you think it likely that life, or something approximating life, has been created additional times in that period? If so what happened to it? Would life from our own lineage destroy it almost immediately? Could it still exist as some sort of extremophile? Would we even be able to recognize such an organism/protoorgamism as being derived from a separate abiogenesis event?

After a lightning storm, there was some weird looking stuff swimming around in a puddle in my backyard. But it was near the chile pequin plant, so I put it in the salsa along with the chile pequin and ate it. I guess it could have evolved into a new race of intelligent beings, but...uh...sorry.

 

[Nostromo]

Do the conditions for abiogenesis still exist or did they cease to exist at some point in the intervening 4 billion years?

Current conditions are different from the conditions 4Ga ago (e.g. there was very little atmospheric oxygen back then), but I don't see why they shouldn't be able to support some kind of abiogenesis.

I would doubt that any knew life would form in the intervening period, as microorganisms would probably guzzle up all the organic molecules, though if it was sufficiently separated from the population at large (as you say, an extremophile of some kind) then maybe.

Being able to recognise such an organism as having an independent lineage would probably rely on it's chemical makeup. If it was not based on DNA then you would strongly suspect it was not related to us.

 

[Wedjat]

There is not enough known about abiogenesis to be sure what exactly is required for new life to spring up. A few things are probable, you need...

some sort of generally non-reactive solvent (such as water)

Something that can form long chains of organic molecules (like carbon)

Adequate energy to drive reactions (sun / geothermal)

At the moment, it is reasonable to assume that most "building blocks" for life are generally used by pre-existing life, and any new life would be immediately out classed in survivability and die off.

 

[Meshach]

After a lightning storm, there was some weird looking stuff swimming around in a puddle in my backyard. But it was near the chile pequin plant, so I put it in the salsa along with the chile pequin and ate it. I guess it could have evolved into a new race of intelligent beings, but...uh...sorry.

Dont fret it, the lightning was probably too strong to spark any life. From what I hear it has to be perfect. You know what they say, after trillions and trillions and trillions of flashes you might get one just right. The bear in Goldilocks only had to test three of the same type of item before he get one "just right". Nacho's and salsa though, sounds good.

 

[Agonaces of Susa]

Miraculous or enchanted conditions are required for abiogenesis.

 

[Cabal]

More people really need better statistics education.

 

[Chesterton]

Dont fret it, the lightning was probably too strong to spark any life.

I don't know. You shoulda seen the stuff:

 

[Friendly.Atheist]

Everything I know about abiogenesis comes from Cosmos.
YouTube - Abiogenesis: The Origin Of Life


By the way, I highly recommend Cosmos to anyone interested at all in science and space. I found it truly inspirational.

 

[Cabal]

I don't know. You shoulda seen the stuff:

*snip*

For some reason that picture really creeps me out.

 

[Chesterton]

For some reason that picture really creeps me out.

I bought those out of the back of a comic book as a kid. That whole advertising ploy of being able to produce little intelligent beings out of a package - I think it left me permanently disturbed.

 

[Cabal]

I bought those out of the back of a comic book as a kid. That whole advertising ploy of being able to produce little intelligent beings out of a package - I think it left me permanently disturbed.

Well, if you're ever bored with Seamonkehs:

Ecosphere Closed Ecosystem, Self Contained Aquarium

 

[troodon]

More people really need better statistics education.

Are you referring to me or Agonaces of Susa?

 

[Cabal]

Are you referring to me or Agonaces of Susa?

Well, to no-one here in particular - just I think most creationists' total ignorance of statistics and statistical mechanics show up at this point in the debate in particular. There are a couple of examples of this in this thread, not from you though - tis a fine OP.

I was at the UK premiere of Expelled on Saturday (KILL ME NOW ) and that's the general sense I got from the creationist members of the audience, so I guess it's just something I've been pondering at the moment.

 

[Gawron]

Posted by troodon:

“Do the conditions for abiogenesis still exist or did they cease to exist at some point in the intervening 4 billion years?”

Given what everyone here knows, that the exact conditions of the earth as it existed some four billion years ago which allowed for pre-biotic evolution are still a matter of some speculation, as well as the process of abiogenesis itself, you are asking a question no-one can really answer.

Also, given the amount of time necessary for this process, how would any of us even know what we were looking at.

But I agree it is fun to speculate.

 

[Maxwell511]

Life formed naturally ~4 billion years ago on this planet, this thread assumes this (hence why it's not in the Cre-Evo Forum. Creationists need not apply.).

What if life started on comets? Like this guy says. Then it is extremely likely that the conditions for the creation of new life continues to exist in the solar system but not earth.

The conditions for abiogensis may never have existed on Earth. This is not a Cre-Evo thing this is a Astrobiologist-Astrobiologist thing. There is genuine scientific debate on this matter. This is one of the areas of science where we can genuinely say "We don't have a clue, but we are trying to figure it out, assume nothing". That is the greatest statement a scientist can make. Why restrict the full awesomeness of this mystery by saying that abiogensis must be assumed to have happened on Earth?

Btw I like the comet idea. The chemistry is different on comets; alot of opportunities for non-equilibrium chemical reactions and life likes metastable non-equilibrium states. Of course it is all way above my head but I find the idea "aesthetically" pleasing.

 

[troodon]

Btw I like the comet idea. The chemistry is different on comets; alot of opportunities for non-equilibrium chemical reactions and life likes metastable non-equilibrium states. Of course it is all way above my head but I find the idea "aesthetically" pleasing.

Then a similar question replaces the old one, how many times has extraterrestrially-created life come to earth, and what happened to it when it got here?

 

[Maxwell511]

Do you think it likely that life, or something approximating life, has been created additional times in that period? If so what happened to it? Would life from our own lineage destroy it almost immediately? Could it still exist as some sort of extremophile? Would we even be able to recognize such an organism/protoorgamism as being derived from a separate abiogenesis event?

I think an interesting discussion relating to this would include some comment on viruses. If we accept that viruses are "life-like", do they come from a second abiogensis type event? They do not fit on the tree of life.

 

[Maxwell511]

Then a similar question replaces the old one, how many times has extraterrestrially-created life come to earth, and what happened to it when it got here?

Of course.

 

[Naraoia]

I agree with Wedjat and Gawron; I think we know too little to say. Even if we had a clear picture of how the thing that evolved into known life arose 4 billion years ago, we wouldn't necessarily know if those were the only conditions it could've arisen under.

Also, given the amount of time necessary for this process, how would any of us even know what we were looking at.

How much time is that? Does anyone really know?

What really made me think about this is the TalkOrigins FAQ about the probability of abiogenesis.

If you took a semi-trailer load of each amino acid and dumped it into a medium size lake, you would have enough molecules to generate our particular replicator in a few tens of years, given that you can make 55 amino acid long proteins in 1 to 2 weeks [14,16].

I'm not saying such back of the envelope calculations are necessarily realistic, but I certainly think they have a point. Most of us would probably expect the formation of life to take an awful lot of time, but is that expectation really justified?

Just thinking aloud here.

I think an interesting discussion relating to this would include some comment on viruses. If we accept that viruses are "life-like", do they come from a second abiogensis type event? They do not fit on the tree of life.

I was going to mention viruses, but in a slightly different context. Well, I was actually going to mention viroids and virusoids. These are very small RNA genomes (some as short as a couple hundred nucleotides) that parasitise plants. I don't find it inconceivable that similarly simple, possibly parasitic proto-life forms that originated on the modern earth could persist instead of being gobbled up by microbes.

As for viruses not fitting on the tree of life, should we expect them to, even if they are descended from the same ancestor as cells? I'm not sure, for two reasons.

(1) They are parasites.

(2) Their genomes are usually very small, and particularly in RNA viruses, mutate rapidly.

Together, these may well lead to genomes that are too small and too heavily modified to contain much phylogenetic information linking them to the rest of the living world (although viral protein structures might be a different matter; I've heard that protein folds preserve common ancestry long after sequences diverged beyond recognition).

DNA viruses with larger genomes could be interesting from this point of view. Anyone know more about them?