Origin of Life

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?
Click to expand...

A good question and the answer to that question is as far as we know that’s exactly the case. That doesn’t exclude life from occurring elsewhere in the Universe as being probable but we don’t have the verified information that it has occurred elsewhere in the Universe. So as far as we know based on the evidence we currently have life as we know it only exists on earth.
 
Mott the Hoople said:
To be honest with you we can sequence DNA and can replicate what DNA does. DNA synthesizes proteins and we can sequence DNA to produce specific proteins. That’s pretty much how a lot modern pharmaceuticals are manufactured. Take synthetic insulin for example.
Click to expand...

True...yet we can't create life. Why?

Human tech can modify life and replicate DNA, but it can't turn something dead into something alive. It's a mystery.
 
Flash said:
How did those seeds get on the other planetary body?
Click to expand...

Unknown. Fermi's Paradox notes there should be a lot of life out there. So far, nada. One theory is that they all died out for one reason or another.

A super nova within 25 light years of Earth would wipe out all life on Earth.
 
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?
Click to expand...

We don’t know that for a fact. It’s not only possible but even probable that life began on our planet, started to evolve and thrive only to have conditions change, decline and die and that this process was repeated until a critical mass of life evolving past a point where it could adapt to changing conditions and then speciation took of radically.

I mean if you think about it primitive life forms have extremely narrow conditions in which they can survive and evolve. So it’s easy to imagine that these early primitive barely meet the description of life cells have a change in say atmospheric oxygen that they could not adapt to and all these primitive cellular life forms went extinct leaving no life on the planet and that this occurred a number of times in cycles until a cycle occurred that was stable enough for long enough for a greater degree of adaptability to occur. Then speciation took off and has lasted an inconceivable amount of time. It’s also probable, given enough time from the present that it could happen again.
 
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/
Click to expand...

Well you also need to include in that analysis lots and lots of 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.
Click to expand...

Exactly except the time frame was probably far larger than 100,000’s of thousands of years. More likely it was many millions of years.
 
Cypress said:
"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.
Click to expand...

Well yes but that’s only because no one was here to observe it. The fact is we honestly don’t know.
 
AProudLefty said:
Another interesting theory is the Infinite Monkey Theorem.

700c2112bef310255b7c160f4b025ad0.gif


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

That would also apply to today's politics. :rofl2:
Click to expand...

We’re not here to discuss Trumpsters! ;-)
 
Cypress said:
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.
Click to expand...

I think #3 is the only rational choice as both #1 and #2 are illogical. That doesn’t mean I’m right. It just means options #1 & 2 are illogical. In fact so illogical they can be pretty much dismissed.
 
Cypress said:
It might not even be a purely scientific question, because it might not be testable or falsifiable.

It is the type of question which might straddle the boundary between science and metaphysics.
Click to expand...

As a hypothesis it’s definitely a valid scientific question. As a scientific theory it would not be for the reasons you stated.
 
Cypress said:
Indeed. Two of my favorite intellectual achievements of ancient Greece: Anaximander articulated a theory of evolution, and Democritus came up with atomic theory.

It is remarkable it took two thousand years for European science to circle back and reacquire a theory of evolution and an atomic theory.
Click to expand...

That’s because the ancients wouldn’t have known what a scientific theory was or how to use them. Yes, they had original thoughts that kind of got the big idea but in practice their conclusion anachronistically viewed from what we know today were laughable. However the underlying philosophy of their ideas were sound. It is a great tragedy that most of the great thinkers of antiquity works and thoughts did not survive antiquity.
 
BidenPresident said:
Odd you think of yourself as a dummy.
Click to expand...

Cyprus is bird dogging you. He’s a PhD level scientist. Just not in biology. LOL

He rarely talks about his professional scientific interest as A. Most of us couldn’t understand it and B. Probably wouldn’t care.

That and their are only a handful of JPP members who really understand science.
 
anonymoose said:
1. Given the right circumstances it is possible for life to evolve from non life . We are proof of that.
2. Quantum mechanics tells us that (most) anything is possible no matter how small the probability.
3. If you consider time to be infinite then there is an infinite amount of time for the right circumstances to occur for life to evolve from non life again. Conversely it is probable we are not the first form of life to have evolved from non life given that the past is infinite.
4. If you consider the universe to be infinite then there’s an infinite number of possibilities for the right circumstances to have occurred for there to be life elsewhere presently.
That’s my take on it.
:dunno:
Click to expand...
Excellent summary Doc.
 
You must log in or register to reply here.
Back
Top