[ExI] Directed Evolution Teaches Nature the Unnatural, Brings Silicon to Life

[spike]

On Fri, Nov 25, 2016 at 4:55 PM, spike <spike66 at att.net> wrote:

>>... They might be, eventually.  But it might take 3 billion years to get
there.
> Or there is something like the blue-green algae equilibrium that 
> carbon-based life was stuck in for a couple billion years, but one 
> that is even more stable.
>
> spike



>... On Behalf Of Giulio Prisco
>...Subject: Re: [ExI] Directed Evolution Teaches Nature the Unnatural,
Brings Silicon to Life

>...So what? 3 short billion years is no big deal ;-) Also, the evolution to
C-Si life on the planets of some old stars could have started long enough
ago for C-Si life to be thriving now. Also, C-Si life could have evolved
directly on some planets without going through C-only life... Giulio


Another possibility: silicon-based lifeforms might exist elsewhere but they
operate at a different time scale than we do, making interaction inherently
limited.

We have two major branches of life on this planet, if you allow me to
simplify away those other kingdoms besides plants and animals.  Since plants
get their fuel by converting sunlight, but we beasts get our energy by
converting other concentrated energy forms, plants and animals operate on
different time scales.  Plants don't move very fast but they move long.

OK cool, so we can argue that life on this planet is energy-limited rather
than materials limited, ja?  Reasoning: there is free carbon around, unused
by lifeforms.  There is a lot more silicon available, but life hasn't
figured out how to use it for anything that I know of.  Biology hipsters, is
silicon used by any lifeform for anything?

OK so we live on the surface of a planet which has looooots of silicon,
available right at the surface.  It is in a highly stable oxide, but carbon
dioxide is also highly stable and lifeforms have figured out how to break
those bonds, put the carbon to work and throw away the oxygen.  

It seems plausible enough to imagine a lifeform that does the same trick
with silicates, somehow converting that to silicones by getting energy from
a nearby star, which can then be used for some kind of metabolism.  That
same vaguely plausible scenario also suggests such lifeforms might operate
on a timescale an order of magnitude slower than our slowest plantlife,
perhaps taking a million years to create a structure analogous to our
bristlecone pines.

There you go, Great Filter explanation.  Envision those old time vinyl LPs.
Perhaps we are given one that was recorded at one revolution per century, we
spin it at 45 RPM and struggle with puzzlement when we  find no music on it.


spike