How life comes to being

[Kookas]

I'm curious about how life comes into being right down at the atomic scale.

 

Are there certain elements that will bond and create an organic material of their own accord given certain environmental conditions? I would love to know what elements could naturally form something that resembles an organism, protein, or similar. It seems reasonable to assume that all life must have originated from something fairly simple which somehow joined with other molecules to become something more complex.

 

Although I also figure that if we knew, we'd probably be developing our own stem-cells and whatnot by now.

 

I'm only making assumptions, though, and I'm not an expert (I would love "the expert view" on this).

Edited August 2, 2011 by Kookas

[CharonY]

I would argue that life is an emergent property. So it is not merely a function of complexity. It has been speculated that the precursors of life came from replicating nucleic acids (and the rest of life is a kind of an add-on).

[iNow]

I enjoy videos such as the below "Origin of Life - Abiogenesis" from Neil deGrasse Tyson since they're both informative and accessible. It's on youtube in five parts.

 

Here are parts 1 & 2:

 

 

 

I enjoy videos such as the below "Origin of Life - Abiogenesis" from Neil deGrasse Tyson since they're both informative and accessible. It's on youtube in five parts.

 

Here are parts 1 & 2:

Here are 3 & 4 & 5:

 

 

Edited August 4, 2011 by iNow

[CharonY]

Nice to have you back, iNow.

[Realitycheck]

sulfur

phosphorous

oxygen

nitrogen

carbon

hydrogen

lightning

heat

 

shake, stir and repeat ^999999999999999

Edited August 4, 2011 by Realitycheck

[Essay]

sulfur

phosphorous

oxygen

nitrogen

carbon

hydrogen

lightning

heat

 

shake, stir and repeat ^999999999999999

Yep, and...

 

Just fyi... [HS = humic substances].

 

Humus, the nexus of the carbon cycle, is an order of magnitude more protective (of life, from damage by UV radiation) than is ozone. And humus existed before life or ozone. Humus is as fundamental to life as sunlight, water, and atmosphere... according to a fairly new book (Steinberg, 2003; isbn: 3-540-43922-6) Ecology of Humic Substances....

 

http://www.springer....8-3-540-43922-6

 

"The discovery of HS formation in the primitive atmosphere has further far reaching consequences for the understanding of ecosystem functioning. The HS are to be granted the role of an independent ecosystem component, such as atmosphere, water, or light, since they come into being simultaneously with early life. This means that living organisms have to adapt to humus or HS-like materials with which they come in contact from the very time they evolve." ~p.36/37

 

Y'know, that original experiment of a primitive atmosphere in a flask...

[with descriptions such as "the water had turned pale yellow and a tarry residue coated..." & "...coated with an oily scum and the water solution was yellow-brown..." ~p.36]

 

...was filled with humic substances after it had reacted for a week.

 

Some of those humic substances happened to be identifiable as previously characterized amino acids. Or in other words, the yellow-brown residue [and/or oily scum] was primordial humus that naturally contained many chemicals, some of which also facilitated and then became incorporated into life and evolution.

===

 

Neat, eh?

Edited August 4, 2011 by Essay

[Greg Boyles]

At the time that life first arose in Earth's oceans, it is believed that the atmosphere contained hydrogen, nitrogen, ammonia and carbon dioxide etc, but no free oxygen. Such an atmosphere is said to be a reducing one rather than an oxidising one, as at present.

 

And oxidizing atmosphere promotes degradation of organic molecules. A reducing atmosphere has the opposite effect on organic molecules.

 

So once our atmosphere acquired free oxygen there was no way that life could ever spontaneously arise from free organic molecules ever again.

 

Watch the first episode of David Attenborough's "Life On Earth". You can find it on youtube.

 

 

As to how precisely proteins, lipids and nucleic acids came together to form the first prokaryote..........who knows.

 

 

But it has been observed that phosolipids do spontaneously form bilayers identical to those found in cell membranes in the form of spherical structures and some simple proteins will spontaneously embed themselves in those phospholipid bilayers.

[Ophiolite]

At the time that life first arose in Earth's oceans, it is believed that the atmosphere contained hydrogen, nitrogen, ammonia and carbon dioxide etc, but no free oxygen. Such an atmosphere is said to be a reducing one rather than an oxidising one, as at present.

This is not generally considered to be the case. See for example, http://www.csun.edu/~hmc60533/CSUN_311/article_references/Sc_Feb93_EarthEarlyAtmos.pdf

At best the atmosphere is thought to have been mildly reducing, with nitrogen and carbon dioxide dominating. There would be some free hydrogen. Formation of amino acids and nucleotides would be difficult in such an atmosphere, but these could have been provided by impacting bolides or at hydrothermal vents.

 

So once our atmosphere acquired free oxygen there was no way that life could ever spontaneously arise from free organic molecules ever again.

It could not so arise from any aqueous body in contact with and in equilibrium with the atmosphere. There would be plenty of submarine and subterranean environments in which these conditions would not apply.

[Greg Boyles]

I enjoy videos such as the below "Origin of Life - Abiogenesis" from Neil deGrasse Tyson since they're both informative and accessible. It's on youtube in five parts.

 

Here are parts 1 & 2:

 

 

 

 

Here are 3 & 4 & 5:

 

 

 

This series of videos was facinating. I hadn't realised they had come as far as that in beginning to understand how the first prokaryotes arose.

 

It all seems very plausible to me.

[Athena]

"The oxygen in the atmosphere is the exhalation of the chloroplasts living in plants (also, for our amazement, in the siphons of giant clams and lesser marine animals). It is a natural tendency for genetically unrelated cells in tissue culture to come together, ignoring species differences, and fuse to form hybrid cells. Inflammation and immunology must indeed be powerfully designed to keep us apart; without such mechanisms, involving considerable effort, we might have developed as a kind of flowing syncytium over the earth, without the morphogenesis of even a flower."

The Lives of a Cell by Lewis Thomas is one of the most exciting books I have read. Exciting in part because it is easy to read, so the reader can enjoy the sensation of being intelligent. We would not exist if it were not for organisms that live inside us and convert matter to energy. Life is societies of organisms working together. Even bacteria must work with us for its own survival, and we are dependent it on for things like digesting our food and giving energy to muscle cells. Sometimes something goes wrong with this balance, but we should not loose sight that life is a balance and co-dependent manifestation. I look forward to future medicine, that pays as much attention to the health and needs of the tiny organism that live within us, as it pays attention to our own bodies. I think this might unlock the mystery of such conditions as chronic fatigue. It does explain conditions such as rheumatic fever.

 

"Most bacteria are totally preoccupied with browsing, altering the configurations of organic molecules so that they become usable for the energy needs of other forms of life. They are, by and large, indispensable to each other, living in interdependent communities in the soil and sea."

[Greg Boyles]

This is not generally considered to be the case. See for example, http://www.csun.edu/...hEarlyAtmos.pdf

At best the atmosphere is thought to have been mildly reducing, with nitrogen and carbon dioxide dominating. There would be some free hydrogen. Formation of amino acids and nucleotides would be difficult in such an atmosphere, but these could have been provided by impacting bolides or at hydrothermal vents.

I couldn't remember the proportions of each gas but I did remember that they were present and that CO2 and N were major components......from reading about Stanley Miller's experiment.

 

Reducing or mildy reducing, the point is that there was no free oxygen or any other oxidant that tend to consume organic compounds.

 

It could not so arise from any aqueous body in contact with and in equilibrium with the atmosphere. There would be plenty of submarine and subterranean environments in which these conditions would not apply.

 

Well the other side of the coin is that now bacteria are every where and they also tend to consume organic molecules and assimilate the carbon. So the fact that life is now absolutely ubiquitous undountedly contributes to the fact that life can never arise again in the same way. Or at least the odds for life arising anew are remote.

[Ophiolite]

Reducing or mildy reducing, the point is that there was no free oxygen or any other oxidant that tend to consume organic compounds.

This point is still open to some debate. The history of oxygen in the Earth's atmosphere is an interesting one. I recommend this paper as an excellent reviewof the issue, though it is eight years old.

[Greg Boyles]

This point is still open to some debate. The history of oxygen in the Earth's atmosphere is an interesting one. I recommend this paper as an excellent reviewof the issue, though it is eight years old.

 

 

Mmmmmm!. So some O2 may have been present due to 'cracking' of H2O, but most of this was consumed by oxidation of reducing gases produced by volcanism leaving only trace amounts. Presumably some of the N was oxidised to nitrogen oxides, some of the H was combined with N to form ammonia abd the volcaning reducing gases included H2S.

 

 

It doesn't seem to entirely discount the assumed general nature of early Earth's atmosphere until cyanobacteria arose. It seems to only bring into question the absolute absence of O2 up until that time.

[micolr]

Truth is, not one scientist on the planet can answer this question. Oh, many will take a stab at it, but none actually know for sure. With scientists these days you hear alot of, "I think..." and "my opinion is..."

 

Science used to be science, where unless it could be duplicated multiple times in some sort of experiment, test tube, or controlled environment, it wasn't even worth calling a hypothesis. Now, heck, as long as you think it sounds good, and you're sporting three letters after your name, it's a rock solid fact that you can write a book about.

 

I long for the day when we go back to being investigators searching for facts, truth, and solid data. For those too young to know what I'm talking about, consider a favorite saying among doctors: "Today's textbooks are tomorrow's joke books."

 

That saying didn't emerge from nothing, it came from generation after generation being taught hypothesis as if it were fact, and doctors trying to make a name for themselves rather than letting the data dictate their decisions.

 

 

[Greg Boyles]

Truth is, not one scientist on the planet can answer this question. Oh, many will take a stab at it, but none actually know for sure. With scientists these days you hear alot of, "I think..." and "my opinion is..."

 

Science used to be science, where unless it could be duplicated multiple times in some sort of experiment, test tube, or controlled environment, it wasn't even worth calling a hypothesis. Now, heck, as long as you think it sounds good, and you're sporting three letters after your name, it's a rock solid fact that you can write a book about.

 

I long for the day when we go back to being investigators searching for facts, truth, and solid data. For those too young to know what I'm talking about, consider a favorite saying among doctors: "Today's textbooks are tomorrow's joke books."

 

That saying didn't emerge from nothing, it came from generation after generation being taught hypothesis as if it were fact, and doctors trying to make a name for themselves rather than letting the data dictate their decisions.

 

 

 

How do you think life arose?