On 7/26/2019 3:07 PM, smitra wrote:
On 23-07-2019 21:26, 'Brent Meeker' via Everything List wrote:
On 7/23/2019 12:07 PM, smitra wrote:
On 23-07-2019 04:10, 'Brent Meeker' via Everything List wrote:
On 7/22/2019 3:55 PM, smitra wrote:
This doesn't address the fundamental problems. People like Leslie
Orgel have explained why metabolism first is a non-starter.
And you think Nick Lane hasn't read Orgel?
Orgel's original arguments can be generalized into a no-go argument
that precludes all existing biochemical models for abiogenesis. This
has been pointed out by Paul Davies. However, Davies then argues
that this means that the problem lies with the fundamental laws of
physics, but one can also circumvent the problems raised by sticking
to ordinary physics and getting to the right structures within which
the conventional models can work.
He has argued on the basis of the difficulties of getting to
functional RNA, and more recently people like Paul Davies have
pointed out the fundamental nature of this problem. My suggestion
is not some new model, it simply makes conventional models such as
e.g. the protocell work better by putting these in a
micro-environment that itself has been forged in far from
equilibrium conditions. The micro-environments break the symmetry
that can steer the chemistry that takes place inside more
coherently in one or the other direction compared to whatever
chemistry can go on in a macroscopic environment.
Keep in mind that the simplest functional living organism is
likely going to be similar to a microbe, involving hundreds of
thousands of different enzymes that are then all necessary to make
each other and maintain and copy the organism. There thus exists a
massive gap from simple chemistry to the simplest self-reproducing
lifeforms. The only plausible solution is then a scenario where
simpler systems that would not function good enough to be able to
reproduce with a multiplication factor of larger than one, can
reproduce with a multiplication factor larger than 1 in a
protected environment.
Which Lane and others postulate to alkaline "white smokers".
This is impossible, because you need to buildĀ structures on the
molecular scale without the enzymes that living organisms have
available. Local thermal equilibrium won't allow chemical reactions
to proceed differently a few atoms distance away at one site of a
large molecule compared to another. So, one needs to consider
processes in an environment where local thermal equilibrium will be
violated on a molecular scale. This can happen in a cryogenic
environment in space where UV radiation creates radical and ions and
occasional cosmic ray interaction causes heating allowing nearby
ions and radicals to form bonds. Such processes have been studied
with the ail of getting to the fundamental building blocks of life,
but that doesn't really work because of the random nature of the
products.
But under those conditions one will also get extremely large
clusters of organics, and they can serve as the housing within which
one can have the right structures for conventional models to work.
Confinement in a small volume is essential as there will be as small
number of structures inside each such system. This means that the
net effect of all the structures inside any particular system will
differ due to statistical fluctuations. In a larger volume, the
average effects of the structures would average out to some mean
effect, also the effect the structures on the surface have on the
chemistry taking place in the entire volume would be less the larger
the volume becomes.
Which is why the huge surface area and fractal-like compartments of
white-smokers are needed for the origin of life:
http://hoffman.cm.utexas.edu/courses/hydrothermal_vents.pdf
I direct your attention to Box 3.
Brent
You can't get such structures down to the molecular scale there.
Catalyzing a reaction on a surface is at molecular scale.
Brent
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