How did life start?

No one knows.

There are some decent guesses, but nothing that can be adequately tested to call it a hypothesis.

Fair enough. It’s true we don’t have much data. I would argue that this does not prevent us from thinking of possible hypotheses, if only because an hypothesis can usefully orient data gathering. If we try hard enough to replicate some primal soup, we may see interesting things happen in them, for example.

I like the idea of primordial soup sitting on a sediment that acted as a catalyst. There are billions of combinations of chemicals and reactions. Considering that there are 6×10^23 molecules in one mole of material (call it 100 grams on average) that means there is plenty of opportunity to combine into something good. The stuff that doesn’t work goes back to the drawing board. Give it an energy source like an undersea vent under pressure and you have a good chance of turning out something in a few hundred million years.
Once it starts, stand back!

Life is nothing more than q collection of complex thermodynamic systems that follow the laws of physics, chemistry, and biology.
While researchers have made proteins, (the basic building blocks of life), and modified genes from inert chemicals, they have not strung them together to make life, yet.
I have no doubt they will. .

That’s my vote anyway.

I have no fucking clue. To me it is the most mysterious question. Even if we can explain how organic molecules / cells started forming, the emergence of consciousness totally blows my mind.

@olivier5 – A scientific hypothesis is defined as a testable, falsifiable guess.

If a guess or suggestion cannot be falsified or tested, it is not a hypothesis, and needs to be refined further before it can gain that title.

Cosmic stork.

Magma trickled into tree sap forming pwetty bubbles of hot awesomeness which rose majestically until reaching space & then burst on a twinkly twonkly star releasing glitterballs of life that rained down on an unsuspecting & previously barren earth…:::& breathe:::

Um. God went down to the tank and mixed him up some mud. Everyone knows that. It’s in the Bible.

@Mariah I find consciousness a bit easier but you’re right it’s another biggy.

@LuckyGuy like the idea of primordial soup sitting on a sediment that acted as a catalyst. ... Give it an energy source like an undersea vent under pressure and you have a good chance of turning out something in a few hundred million years.

Yes, the soup could have been structured through a layer of clay or another. Funny how Genesis springs to mind… But we don’t have that many hundred million years for the process to happen in the standard history of life on earth. I mean life appeared very early. Traces of photosynthesis (a very complex biochemical feat) appear in the geological record as early as 3.8 bl YBP.

@Seek A scientific hypothesis is defined as a testable, falsifiable guess.

Correct, but the ideas of the primal soup or panspermia are perfectly testable.

No wait, it started with a kiss…hot chocolate

@olivier5 “But we don’t have that many hundred million years for the process to happen in the standard history of life on earth. I mean life appeared very early. Traces of photosynthesis (a very complex biochemical feat) appear in the geological record as early as 3.8 bl YBP.”

That still leaves around 6–700,000,000 years from the formation of the Earth.

@Darth_Algar Yes. Part of which is taken up by some cooling period during which the surface was melted lava. And another part taken by the time necessary to evolve some photosynthetic capacity. Life must have started circa 4.1 or 4.2 bl YBP, after 1 or 2 hundred million years of “soup”.

@olivier5 – “Correct, but the ideas of the primal soup or panspermia are perfectly testable.”

ORLY? Perfectly testable?

If you have some special knowledge of the conditions under which life began and would like to have them tested, you should probably be, like, talking to some scientists or some shit.

Scientists are already testing panspermia. Why do you think they sent robots to Mars and on a comet, or analyse organic chemistry in distant interstellar gaz clouds and stuff? As for the idea of the primordial soup, the first experiment dates back to 1952.

They don’t need clues from little me.

@olivier5 Radiometric data indicates the Earth to be 4.54 billion +/- 1% years old. 500, 400, 300, 200, even 100 million years is still a lot of time for 6×10^23 molecules for every 100 grams to turn into something good – especially if you are applying heat, pressure, water, and nutrients like those found near sea vents.

I lean toward panspermia. I have a feeling that when we finally are able to really look we’ll find it all over the place in the universe.

Soup. I figure all the ingredients were here,being bombarded with radiation (since there was no ozone layer to protect the planet ) and then the radiation started mutating and ‘stirring ’ the soup.

Now here we are. Cluster Fuck Stew ;)

@LuckyGuy I think about 200 ml years. Which is still a lot of time but there’s much ground to cover during that time. A whole RNA world would have to develop before photosynthetic unicellulars can appear.

There is an intriguing theory that life is a consequence of the second law of thermodynamics, which states that energy dissipates and becomes less usable. Life might appear to violate the second law by concentrating energy, but this is explained by pointing out that the increased entropy of solar energy is not compensated by the concentration of energy in life. As I understand it, what English is saying is that life forms actually increase the net entropy. The energy dissipated by life forms is greater than what they store. Therefore the formation of life forms accelerates entropy and is therefore a much more likely event than we had previously supposed.

The theory goes beyond the formation of life to how organisms evolve. The theory says that formation of structures in an organism is also a way of increasing entropy and the role of natural selection is to choose those structures that are most effective. From the 10,000 foot level, one can say that evolution in general is just the result of this process. Those species that survive are those that are the best at reproducing themselves, thus accelerating the rate of entropy.

Not sure I understand England’s idea, but I am sympathetic to the possibility of some physical phenomenon or force favoring the appearance of life, “pushing for life” so to speak, because life appeared so early on our planet, almost as early as it possibly could. It’s not like Mother Nature tried and tried for eons to create life and finally succeeded against all odds. It looks more like it was bound to happen, and reasonably straightforward.

Don’t discount all the other possible locations for the“beginning of life” to have happened.

Probability is a bitch when you have the whole universe to play with.

Interestingly re. panspermia, the earth was subjected to heavy bombardment of meteorites at about the same time as life supposedly appeared here: the Late Heavy Bombardment was an event thought to have occurred approximately 4.1 to 3.8 billion years ago. During this interval, a disproportionately large number of asteroids are theorized to have collided with the early terrestrial planets in the inner Solar System, including Mercury, Venus, Earth, and Mars. Evidence for the LHB derives from lunar samples brought back by the Apollo astronauts. Isotopic dating of Moon rocks implies that most impact melts occurred in a rather narrow interval of time.

These were the early days of the solar system, and it was raining asteroids. Almost all the craters on the moon are thought to have been made during that period.

The coincidence with the start of life on earth leads proponents of panspermia to say that the LHB meteorites brought life here…

@olivier5 So many molecules… so much time…

I have a 2 kg chunk of Anorthosite estimated to be 2.2B years old. The rock is so hard and has such sharp crystalline feature where I broke off a piece. I imagine that somewhere deep inside that chunk is evidence of Archean or Proterozoic life.
It is my hope that in the future researchers will be able to look inside with the latest and greatest equipment of the day and point out the genetic makeup of the critters that left their mark so long ago..

@olivier5 what did you mean by “I think about 200 ml years…” above. 200 million years for what?

@LuckyGuy So many molecules… so much time…

Yes, but I wonder what are the odds that these molecules just bounced off each other and made life happen.

Are you aware of the chicken-and-egg problem posed by the relations between proteins and DNA? Every time a cell divides, it replicates its DNA so that one copy of the original DNA can be passed to each daughter cell. Now, DNA cannot replicate without complex proteins called polymerases catalysing the reaction AND polymerases are so complex that the only way to produce them is through DNA-informed biosynthesis. So DNA needs polymerases to exist (at least to replicate, hence to work as a database of proteins for living organisms), and vice-versa, polymerases need DNA to exist… Chicken-and-egg.

No cause to yell “irreducible complexity”, pointing at one idol or another. But to my knowledge this issue has yet to be solved convincingly. E.g. another type of catalyst or just a much much simpler DNA polymerase primed the pump, or RNA started it all in the theorized RNA world.

@Dutchess_III For life to appear in the “primordial soup”.

Wait….are you saying you think primitive life first appeared only 200 million years ago @olivier5?

@Dutchess_III No, that’s not what I am saying.

That isn’t what you were saying?

I am confused, then, and here is why:

You said, ” I think about 200 ml year…”
I said, “For what?”
You said, “For life to appear in the “primordial soup.”
I said, “You think life first appeared only 200 million years ago?”
You said, “No, that’s not what I’m saying.”

Please explain what you were saying!

@olivier5 I get it. But all around me I see examples of catalysts helping/encouraging reactions that would normally not take place or would take a long time with a low yield. Catalytic converters on cars, certain ceramics, platinum. palladium….minerals

Here’s a recent reaction that really intrigues me. I have an unlined fish pond that is dug into clay soil with a volume of about 1000 gallons. 4000 liters I have a couple of air bubblers and a high pressure water fill so the water is mixed all the time. For about 6 months the water was so cloudy I could not see the fish. I could only see about 3 inchs into it.
I asked a question here and a kind Chemist Jelly told me to add a cationic flocculent Surely that is a made up term. Right? :-). But I went online and found some! I dribbled in 2 ounces (60 ml) of the clear liquid. In 4 hours the pond was clear!!! That small amount of chemical caused the fine clay particles that were in suspension to aggregate into larger clumps and settle to the bottom! It was incredible! Can you see where I’m going with this?.
What if there were a catalyst like the flocculent that fell into the soup. It is possible it would encourage molecules to interact with each other and form something they would not do on their own. They could potentially coalesce, settle to the bottom and be treated with heat, salt water, sulfur, and pressure for millions of years. Proteins.

@Dutchess_III, to answer your question in case @olivier5 can’t answer you right away….
Here is a rough time line. just rounding numbers here.
4.5 B the Earth is formed.
4.0 B asteroid bombardment.
200 million years of soup cooking, or 300, or 500 million. When you make a 10 minute egg do you count the time the oven is turned on or do you only count the boiling time?
There is plenty of evidence that life was around at 3.8 to 4 B years ago. Maybe it formed during the bombardment. Maybe it took time to cook.

@olivier5 How did I do?

Oh. He’s saying it took 200 million years for the amino acids and proteins and hydrogen, etc.to begin to coalesce.

OK, now I can follow the discussion.

Thanks. We’re lucky to have you, @LuckyGuy.

Very good overview, Lucky.

olivier5 Thanks. I didn’t want to put words in your mouth. We’re on the same page. We might differ by line or word number but we are very close.

By the way. The flocculent is safe for fish! I find that even more incredible! It doesn’t take the dissolved oxygen out of solution. It doesn’t clear out the food. It doesn’t affect the fish’s gills.
It just works. Amazing.
(One negative effect. Since the bigger fish can see the little ones easily now more of the little ones are getting eaten by bigger fish.)

@LuckyGuy Yes, i see where you’re going. Catalysed reaction can indeed be spectacular but your flocculent pales in comparison with any biological enzyme, and a fortiori with the enzymes involved in DNA wizardry. Have a look at these beasts.

https://upload.wikimedia.org/wikipedia/commons/thumb/6/61/1axc_tricolor.png/555px-1axc_tricolor.png

https://en.wikipedia.org/wiki/DNA_polymerase#/media/File:PDB_1xhz_EBI.jpg

These are only 2 of a long series

Their spatial shape is of course essential to their function. They look like microscopic machines. This shape of each DNA polymerase or ligase or whatever, is itself the result of several operations of “shaping” that the originally linear protein polymere is subjected to by RNA and other enzymes.

THAT is what it takes nowadays to replicate DNA, a pretty complex enzymatic machinery..Such a complex system cannot have happened just by chance, from innert material being rocked and shocked together.

Seems to me, it takes the RNA world hypothesis to solve this problem, the solution is simple: there was a much simpler form of the DNA-RNA-protein complex. It was once just RNA, the middle piece of the puzzle, and it gradually learnt to “domesticate” proteins, and later to write itself down on a more durable support: DNA.

Still with me there?

It’s interesting to me that we know so little about the planet we inhabit , and the universe it flies through…

Both have mysterious beginnings with mind blowing outcomes.

More interesting, or frustrating, is that the most important questions man has about the universe, our planet, and death, may never be answered…

I like thinking about it though.

When I’m working out with free weights I always try and ‘max out,’ or lift as much as possible. My body feels the strain, and feels that much more ,and my muscles will be inadequate. I feel a similar feeling when attempting to contemplate the universe. It’s vast, mysterious , cold expanse. The sheer amount of time that has passed since dinosaurs roamed. The unknown of death. It’s as if I am attempting to lift far more than my body is capable of. I can’t speak for others, but it seems to overwhelm my mind to try and think of how much is happening, and how inconsequential my role must be compared to the rest of what’s going on.

Sometimes I feel like a fly fart, caught in a hurricane…..

@olivier5 Oh I agree with you. DNA would not have been the first step. RNA or something even simpler is much more likely.
In an early Logic course we learned how to perform complex operations by simplifying down to their essence. E.g. How do you get to the top of a ladder. 2 operations. Operation 1: Get on to the first step. Operation 2: move from step N to step N+1.
Maybe the “ladders” were there in the form of minerals and ocean currents and heat pushed a bunch of C, A, G, T, into the same area. After all, they are nearly the same size.

I’m a bit of a fossil hound. If you collect as well, you know that you often find groups of the same body part from hundreds of individuals rather than hundreds of complere individuals. (Frustrating) For example: if you are looking for Trilobites. (an animal with 3 sections call them: head, body, tail.(not the correct terms but close enough for this discussion)
You can find an are of rock exposed by construction or the Erie Canal and look. Unfortunately you will very likely find dozens of heads but no bodies.. In another area you will find only tails, while in another only bodies. Why? Because the ancient water currents and conditions were right for that spot to have the heads settle out while the bodies moved downstream (or upstream, I forget) .
Maybe some settled minerals acted the same way and helped encourage the correct size concoctions to make some simple messenger RNA.

(The Erie Canal in Western NY is fantastic for fossil hunting by the way. 450 Mya Cambrian).
(The Southern Tier near Dansville and Wayland has exposed rock from the Devonian period 350Mya. I have decorated my garden with Devonian fossils of Brachiopods and others.)

@LuckyGuy Different body parts could sediment in different parts of a river, yes, depending on their respective floatability.

@MrGrimm888 I feel a similar feeling when attempting to contemplate the universe. It’s vast, mysterious , cold expanse.

I know the feeling. And yet according to Omar Khayyam: in the path of science, the stars are a thousand times more helpless than you.