Question on Abiogenesis

[The Happy Humanist]

Many times I have heard it said that evolutionists believe that all life on earth descended from a common ancestor, a "single organism." I always assumed this meant a single "type" of organism, but everywhere I've read it, it seems to imply that it really was "just one organism." Can someone clarify this for me?

Thanks.

[ST88]

The prevailing theory of abiogenesis as I understand it is that somewhere in the vast sea of organic matter that was the early Earth, one single spontaneous chemical reaction produced the first vestiges of life. That is, there was a first organic chemical that was able to reproduce itself. This may have happened due to atmospheric conditions, cosmic rays, aliens from Tralfamadore, or dumb luck. Billions and billions of pieces of organic matter didn't go through this transformation, just this one piece did.

From there, any one of the reproductions could have mutated enough to give rise to a different type of chemical structure, and so on. I've understood this to be one single individual, as the spontaneous creation of multiple complex organic chemicals we might call "organisms" is more unlikely than the spontaneous creation of just one organism.

[The Happy Humanist]

The prevailing theory of abiogenesis as I understand it is that somewhere in the vast sea of organic matter that was the early Earth, one single spontaneous chemical reaction produced the first vestiges of life. That is, there was a first organic chemical that was able to reproduce itself. This may have happened due to atmospheric conditions, cosmic rays, aliens from Tralfamadore, or dumb luck. Billions and billions of pieces of organic matter didn't go through this transformation, just this one piece did.

From there, any one of the reproductions could have mutated enough to give rise to a different type of chemical structure, and so on. I've understood this to be one single individual, as the spontaneous creation of multiple complex organic chemicals we might call "organisms" is more unlikely than the spontaneous creation of just one organism.

Mmmm...I dunno...that does make it sound kind of... miraculous. If the conditions were right, why couldn't it have started happening in several places? Would that upset the family tree somehow?

[bernee51]

The prevailing theory of abiogenesis as I understand it is that somewhere in the vast sea of organic matter that was the early Earth, one single spontaneous chemical reaction produced the first vestiges of life. That is, there was a first organic chemical that was able to reproduce itself. This may have happened due to atmospheric conditions, cosmic rays, aliens from Tralfamadore, or dumb luck. Billions and billions of pieces of organic matter didn't go through this transformation, just this one piece did.

From there, any one of the reproductions could have mutated enough to give rise to a different type of chemical structure, and so on. I've understood this to be one single individual, as the spontaneous creation of multiple complex organic chemicals we might call "organisms" is more unlikely than the spontaneous creation of just one organism.

Mmmm...I dunno...that does make it sound kind of... miraculous. If the conditions were right, why couldn't it have started happening in several places? Would that upset the family tree somehow?

It may very well have happened in various places - perhaps in many places where the conditions were right. Those that were not fit to survive and reproduce had their family tree nipped in the bud.

[ST88]

Mmmm...I dunno...that does make it sound kind of... miraculous. If the conditions were right, why couldn't it have started happening in several places? Would that upset the family tree somehow?

Well, given the fact that there were billions of years in which it did not happen, and that it, in fact, did happen, it would also be possible to say that it was miraculous that it didn't happen for all the time that the organic soup lay dormant.

[bigmrpig]

It is also possible that the conditions, though rare, were perfect in a small area, but the supposed reaction occured and created more than one organism in the beginning, at the same time. A small blob of life, so to speak.

[Bonnie]

It is also possible that the conditions, though rare, were perfect in a small area, but the supposed reaction occured and created more than one organism in the beginning, at the same time. A small blob of life, so to speak.

This could be. Scientists seem to have more theories about abiogenesis and the start of life on Earth than can even be researched. The most common theory seems to be the "Primordial Soup" theory.

In 1953 two scientists named Miller and Urey designed an experiment to test the "Primordial Soup Theory" that combined chemicals that were known to be abundant at the time -- which were water vapor, hydrogen, methane, and ammonia -- with energy (static electricity, simulating the lightning that was thought to have been abundant in Earth's violent early atmosphere). This experiment produced organic chemicals, namely amino acids, sugars, lipids, and the bases of genetic material, from the inorganic chemicals listed above. These are all of the building blocks of life. Combined in the right way, they make up a living organism.

Maybe scientists seem to refer to only one "common ancestor" because they think that the first truly "living" organism, that is one that contains all of the properties of life, was so simple that it had to only have combined all of the building blocks of life in a certain way.

However, what do you mean when you say "more than one organism"? Because it is pretty much a consensus that all of the earliest organisms were pretty much the same: Prokaryotic (resembling Bacteria: single celled, no nucleus), chemosynthetic (obtaining energy from inorganic chemicals), and having RNA as their form of genetic material.

Forgive me if you already know all of this stuff, I'm not trying to insult your intelligence or anything, I simply do not know your specific scientific knowledge.

I believe that it is possible for there to have been more than one organism that formed when our "Common Ancestor" came to be. However, life forming out of nonliving organic materials is highly improbable, no matter how good the conditions are. If this happens once, if one organism were to form when there were no others around, wouldn't it be more likely for that one to prevail than for another one to form independently? Its existence would disrupt the balance of chemicals and conditions that allowed it to form in the first place.

Also, consider how long the earth was around before life was thought to have originated. The earth is thought to be somewhere between 5 and 5.5 billion years old. The first organisms were thought to pop up somewhere around 3.5 billion years ago. That's a long time, even with giving the Earth time to cool down from a ball of molten material to a ball of cooler, solid material.

Mmmm...I dunno...that does make it sound kind of... miraculous. If the conditions were right, why couldn't it have started happening in several places? Would that upset the family tree somehow?

Even if the conditions were right, that still doesn't mean that it will happen right away, or even at all. Given enough time, and if the conditions were perfect and stayed perfect in that time, it would have to happen. The conditions were right for millions of years for life to happen, but it is still improbable for the right building blocks of life to come together at the right time. I would agree that it is miraculous. Maybe not in the religious sense of the word "miracle," but it is amazing and awesome and that is why it is so interesting to me.

But then again I could be wrong about the probability of life forming in the Primordial Soup -- perhaps it was highly probable. Perhaps the Soup was so big and vast and had all the right conditions and that the time needed to create life from nonliving chemicals was actually shorter than I'm considering. In that case, then it could be quite possible for different organisms to form at different places in the Primordial Soup.

[Nyril]

The earth is thought to be somewhere between 5 and 5.5 billion years old.

Simply for accuracy's sake, the number is about 4.55 billion years (plus or minus about 1%).

[Bonnie]

Simply for accuracy's sake, the number is about 4.55 billion years (plus or minus about 1%).

My bad. That's what I get for going off my memory.

However, I think that's what my biology teacher stated. He might be going off of outdated information... since he himself is outdated as well...

Then again he might have even been there for all I know.

Thanks for checking up on accuracy.