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Selfsim
2013-Oct-07, 08:55 PM
From the threads .. "Did life here, start out there?" and "Pre-life evolution, ecological niches, complex systems". (I thought it deserved its own dedicated thread).

Did life originate from a global reactor? (http://onlinelibrary.wiley.com/doi/10.1111/gbi.12025/pdf)
by E. E. STU€EKEN, R. E. ANDERSON etal, Geobiology 2013:



Many decades of experimental and theoretical research on the origin of life have yielded important discoveries regarding the chemical and physical conditions under which organic compounds can be synthesized and polymerized. However, such conditions often seem mutually exclusive, because they are rarely encountered in a single environmental setting. As such, no convincing models explain how living cells formed from abiotic constituents. Here, we propose a new approach that considers the origin of life within the global context of the Hadean Earth. We review previous ideas and synthesize them in four central hypotheses:

(i) Multiple microenvironments contributed to the building blocks of life, and these niches were not necessarily inhabitable by the first organisms;
(ii) Mineral catalysts were the backbone of prebiotic reaction networks that led to modern metabolism;
(iii) Multiple local and global transport processes were essential for linking reactions occurring in separate locations;
(iv) Global diversity and local selection of reactants and products provided mechanisms for the generation of most of the diverse building blocks necessary for life.

We conclude that no single environmental setting can offer enough chemical and physical diversity for life to originate. Instead, any plausible model for the origin of life must acknowledge the geological complexity and diversity of the Hadean Earth. Future research may therefore benefit from identifying further linkages between organic precursors, minerals, and fluids in various environmental contexts.


I find this model to be a starting point, which at least, realises the degree of complexity of what we're really talking about when it comes to abiogenesis and "The Hunt" for life beyond Earth. I doubt the authors of this would see abiogenesis as occurring from anything as simplistic as, say for example, a Miller-Urey conducted experiment inside a lab-flask(?)

Selfsim
2013-Oct-07, 08:58 PM
The link seems to have been broken (maybe by our ultra reliable board software)?

Here's another attempt (http://onlinelibrary.wiley.com/doi/10.1111/gbi.12025/pdf) (my fourth so far, in fact).

Paul Wally
2013-Oct-07, 09:33 PM
I find this model to be a starting point, which at least, realises the degree of complexity of what we're really talking about when it comes to abiogenesis and "The Hunt" for life beyond Earth. I doubt the authors of this would see abiogenesis as occurring from anything as simplistic as, say for example, a Miller-Urey conducted experiment inside a lab-flask(?)

Thanks. I just started reading now.


E. E. STU€EKEN, R. E. ANDERSON etal


... life may not have been the product of a highly unlikely
sequence of events, but instead the gradual outcome of a
number of frequently occurring and inter-related processes.

Doesn't look good for you rare earther's :p

Selfsim
2013-Oct-08, 09:33 PM
Its interesting comparing Pross' DKS 'driven' approach with this one.

This approach is more along the lines of Self-Organising Complexity, in which the explicit external environment(s), (summarised in this paper), drive the system to self organise. (This would seem to be the default approach, mostly favoured by Colin R and Paul W(?)).

Pross' Evolution-themed approach (Evolving Complexity) is more open-ended, where systems evolve over time into different systems (and keep doing so).

The difference between the approaches is that the externally imposed 'the global reactor' is the implied cause, as opposed to a system attractor state, (dynamic kinetic stability), hypothesised as being universal in self-replicating systems.

Colin Robinson
2013-Oct-22, 09:41 PM
From the threads .. "Did life here, start out there?" and "Pre-life evolution, ecological niches, complex systems". (I thought it deserved its own dedicated thread).

Did life originate from a global reactor? (http://onlinelibrary.wiley.com/doi/10.1111/gbi.12025/pdf)
by E. E. STU€EKEN, R. E. ANDERSON etal, Geobiology 2013:


Here, we propose a new approach that considers the origin of life within the global context of the Hadean Earth. We review previous ideas and synthesize them in four central hypotheses:

Multiple microenvironments contributed to the building blocks of life, and these niches were not necessarily inhabitable by the first organisms;

At first glance the Hadean period seems far from life-friendly. It is an important point that niches which were not necessarily inhabitable even by the first organisms (let alone by creatures like us!), may nonetheless have contributed to the process which led to life.

Noclevername
2013-Oct-23, 12:32 AM
It did appear to take a few hundred million years of planet-wide trial and error, plus complex chemicals being washed all over the planet by global oceans, to result in biology. Early Earth might be considered a king-sized bioreactor.

Hlafordlaes
2013-Oct-23, 01:24 AM
I think this together with the Pross approach is promising. Not an 'or,' but an 'and.'

In general, when I've tried to state my feeling in LiS threads that abiogenesis was a system-wide process, it is similar to this but would include compounds and sources coming in from bombardment, too. Gut feeling really, but comes some of the links I posted earlier in the year citing evidence for certain combos in asteroid samples.

Selfsim
2013-Oct-23, 05:49 AM
Personally, I don't really see this study as coming up with anything particularly revolutionary.
I see it being more of a good summary of a whole bunch of other studies, and as pulling together a lot of ideas in the one paper.

If one is going to talk about abiogenesis on (Hadean) Earth, then the contents of this paper, is what one is actually talking about.

I see nothing supporting the idea of inevitability of life emerging, although if one does see this, then the lead up to that quantum leap of faith, is nicely laid out in this paper.

marsbug
2013-Oct-23, 06:15 PM
It is more of a pulling together of many ideas than an advancing of new ones, but pulling together all these ideas does paint a complete picture that I've never encountered before. That many different complex systems interacted to lead up to life, that no single system had all the attributes of life, and that they were distributed across a wide range of environments, is an important idea to realise ; There was no single 'magic moment'.

publiusr
2013-Oct-26, 07:51 PM
There may have been more smokers in the past--I wonder how near shore some may have gotten. The funneling of sea water across a rift that narrows inland can let water with organics go over the top into pools where more gentle action can take place.

I think one of the reasons folks didn't believe in evolution was you just had a warm pond and something kind of happened. To many, it seemed like you were simply substituting one miracle for another.
Now we know about impacts, huge tides, extremophiles, etc. This is where the catastrophists came to the fore, even though gradualists rejected them out of hand. You need both dynamic forces and quiet tidepools in combination. Enough chop to get things churned up--but also enough quiet times to give early life a chance to grow.