Origin of Life

C

Cypress

Well-known member
I currently lean towards number two, but keep an open mind.
It would be nice if we had more intel on emergence: the transition from non-life to life. There is zero chance something as mind boggling complex as even a single eukaryotic cell just appeared on the scene without an incredible sequence of interim events. Unless we were seeded from another planetary body.

Three Possible End-Member Scenarios for the Origin of Life

1) The origin of life may have been a miracle.
2) The origin of life was an event fully consistent with chemistry and physics, but one that was almost infinitely unlikely and required an improbable sequence of numerous steps.
3) The universe is organized in such a way that life is an inevitable consequence of chemistry, given an appropriate environment and sufficient time.

Source credit: Dr. Robert Hazen, George Mason University
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Cypress said:
I currently lean towards number two, but keep an open mind.
It would be nice if we had more intel on emergence: the transition from non-life to life. There is zero chance something as mind boggling complex as even a single eukaryotic cell just appeared on the scene without an incredible sequence of interim events. Unless we were seeded from another planetary body.
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I think life is just another part of the evolution of the universe.
 
AProudLefty said:
It's a form of the junkyard tornado fallacy.
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That is a good one - a tornado blows the junkyard into a 747 jet.

We are obviously missing almost all the details of what happened before primitive archea and primitive eukaryotic cells.

We can synthesize amino acids under laboratory conditions. But that is still one thousand light years away from synthesizing something as complex as a cell.
 
BidenPresident said:
I think life is just another part of the evolution of the universe.
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I am hoping we find microbial life in our solar system. Otherwise we will never really know if life on earth is unique, or whether life is an expected outcome of chemistry and physics.
 
Cypress said:
I currently lean towards number two, but keep an open mind.
It would be nice if we had more intel on emergence: the transition from non-life to life. There is zero chance something as mind boggling complex as even a single eukaryotic cell just appeared on the scene without an incredible sequence of interim events. Unless we were seeded from another planetary body.
Click to expand...

As child of a scientist and mother of another, and a spiritual being connected to all the life on the this planet (like all of us)... I'm going with #3.

We simply do not know enough about life forms on THIS planet, let alone others. We don't know as much of biochemistry as we want to. We can sequence DNA, but we cannot replicate what it does.

Given our infantile state of growth as a species, I'd say that that is an excellent thing!
 
Cypress said:
I am hoping we find microbial life in our solar system. Otherwise we will never really know if life on earth is unique, or whether life is an expected outcome of chemistry and physics.
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You are a man of philosophy. What would it mean to you as a person if it was determined that this little rock ball at the edge of a meh galaxy contained the only life forms that ever existed?
 
Cypress said:
That is a good one - a tornado blows the junkyard into a 747 jet.

We are obviously missing almost all the details of what happened before primitive archea and primitive eukaryotic cells.

We can synthesize amino acids under laboratory conditions. But that is still one thousand light years away from synthesizing something as complex as a cell.
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I lean more towards #3. Reproduction is the keyword. That is covered in Richard Dawkins' The Blind Watchmaker.
 
ThatOwlWoman said:
You are a man of philosophy. What would it mean to you as a person if it was determined that this little rock ball at the edge of a meh galaxy contained the only life forms that ever existed?
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If life on earth resulted from a complex series of extremely improbable events, and life is thus expected to be extremely rare in the universe, it would just make me think about how precious and fragile life is. It would be humbling to say the least.
 
Cypress said:
If life on earth resulted from a complex series of extremely improbable events, and life is thus expected to be extremely rare in the universe, it would just make me think about how precious and fragile life is. It would be humbling to say the least.
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I respect that. Thanks.
 
ThatOwlWoman said:
As child of a scientist and mother of another, and a spiritual being connected to all the life on the this planet (like all of us)... I'm going with #3.

We simply do not know enough about life forms on THIS planet, let alone others. We don't know as much of biochemistry as we want to. We can sequence DNA, but we cannot replicate what it does.

Given our infantile state of growth as a species, I'd say that that is an excellent thing!
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great points

What is weird to me is that even after 4 billion years, life apparently only evolved once on earth. Every living thing today is a genetic descendent of those first microbes from 3.8 billion years ago.

I just wonder why life did not evolve more than once on earth? If life is so resilient, why didn't different genetic strains of life evolve, or why didn't entirely different life forms evolve here?
 
Cypress said:
great points

What is weird to me is that even after 4 billion years, life apparently only evolved once on earth. Every living thing today is a genetic descendent of those first microbes from 3.8 billion years ago.

I just wonder why life did not evolve more than once on earth? If life is so resilient, why didn't different genetic strains of life evolve, or why didn't entirely different life forms evolve here?
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Funny you should ask that. It has been discussed and studied already.

IN 4.5 billion years of Earthly history, life as we know it arose just once. Every living thing on our planet shares the same chemistry, and can be traced back to “LUCA”, the last universal common ancestor. So we assume that life must have been really hard to get going, only arising when a nigh-on-impossible set of circumstances combine.

Or was it? Simple experiments by biologists aiming to recreate life’s earliest moments are challenging that assumption. Life, it seems, is a matter of basic chemistry – no magic required, no rare ingredients, no bolt from the blue.

And that suggests an even more intriguing possibility. Rather than springing into existence just once in some chemically blessed primordial pond, life may have had many origins. It could have got going over and over again in many different forms for hundreds of thousands of years, only becoming what we see today when everything else was wiped out it in Earth’s first ever mass extinction. In its earliest days on the planet, life as we know it might not have been alone.

https://www.newscientist.com/article/mg23130870-200-life-evolves-so-easily-that-it-started-not-once-but-many-times/
 
AProudLefty said:
Funny you should ask that. It has been discussed and studied already.

IN 4.5 billion years of Earthly history, life as we know it arose just once. Every living thing on our planet shares the same chemistry, and can be traced back to “LUCA”, the last universal common ancestor. So we assume that life must have been really hard to get going, only arising when a nigh-on-impossible set of circumstances combine.

Or was it? Simple experiments by biologists aiming to recreate life’s earliest moments are challenging that assumption. Life, it seems, is a matter of basic chemistry – no magic required, no rare ingredients, no bolt from the blue.

And that suggests an even more intriguing possibility. Rather than springing into existence just once in some chemically blessed primordial pond, life may have had many origins. It could have got going over and over again in many different forms for hundreds of thousands of years, only becoming what we see today when everything else was wiped out it in Earth’s first ever mass extinction. In its earliest days on the planet, life as we know it might not have been alone.

https://www.newscientist.com/article/mg23130870-200-life-evolves-so-easily-that-it-started-not-once-but-many-times/
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"And that suggests an even more intriguing possibility. Rather than springing into existence just once in some chemically blessed primordial pond, life may have had many origins. It could have got going over and over again in many different forms for hundreds of thousands of years"

I have heard that hypothesis too; the multiple evolutionary events hypothesis..

I like the idea as a hypothesis. But the scientist in me sees it as speculative at this time.
 
Cypress said:
"And that suggests an even more intriguing possibility. Rather than springing into existence just once in some chemically blessed primordial pond, life may have had many origins. It could have got going over and over again in many different forms for hundreds of thousands of years"

I have heard that hypothesis too; the multiple evolutionary events hypothesis..

I like the idea as a hypothesis. But the scientist in me sees it as speculative at this time.
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Here's another good article: https://www.theguardian.com/science/2009/feb/15/microbes-earth-tree-of-life
 
Cypress said:
I currently lean towards number two, but keep an open mind.
It would be nice if we had more intel on emergence: the transition from non-life to life. There is zero chance something as mind boggling complex as even a single eukaryotic cell just appeared on the scene without an incredible sequence of interim events. Unless we were seeded from another planetary body.
Click to expand...

I'm leaning towards number three. This part of number two put me off choosing it: "one that was almost infinitely unlikely and required an improbable sequence of numerous steps."
 
AProudLefty said:
Here's another good article: https://www.theguardian.com/science/2009/feb/15/microbes-earth-tree-of-life
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"Scientists have called for a "mission to Earth" to hunt for evidence of a second genesis that gave rise to life, but not as we know it."...."must be open to the possibility that there's more than one tree of life," Davies said.

It is still just an educated guess, but this kind of creative thinking and open mindedness is the trademark of good science.

At this time, available evidence indicates that life, curiously, evolved only once on earth. But a search for evidence of multiple evolutionary events is something we should do. Because I am not the only one who thinks it is a little weird that life only evolved once on earth in four billion years, especially if our expectation is that life is common, resilent, and ubiquitous in the universe.
 
christiefan915 said:
I'm leaning towards number three. This part of number two put me off choosing it: "one that was almost infinitely unlikely and required an improbable sequence of numerous steps."
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Another interesting theory is the Infinite Monkey Theorem.

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https://en.wikipedia.org/wiki/Infinite_monkey_theorem

That would also apply to today's politics. :rofl2:
 
christiefan915 said:
I'm leaning towards number three. This part of number two put me off choosing it: "one that was almost infinitely unlikely and required an improbable sequence of numerous steps."
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I get it. These three choices were just endpoints. There are gradations between them.

I actually want to choose option 2.5, so to speak. Something in between life being ubiquitous, and life being infinitesimally rare.
 
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