[extropy-chat] extropy-chat] Hello Fellow Extropians...
hal at finney.org
Mon Mar 13 01:06:10 UTC 2006
Mark Lyons writes:
> Here's where it gets interesting. These folks have discovered a new form of
> life that has characteristics of both bacteria and viruses, but lies
> somewhere in between the two:
Nanobacteria (sometimes spelled nannobacteria) are a fascinating
topic. These are super-small (20-200 nm) spherical objects seen
in a variety of biological and mineral substrates which resemble
life forms. Whether they are actually living or not is still an
open question. This company nanobac.com is strongly pushing the life
theory but it is worth bearing in mind that there are opposing views.
A good overview of the current situation is available at wired.com:
Some of the contrary evidence has involved failure to find RNA or DNA,
and there is at least limited evidence that crystalline materials may be
able to "reproduce" in biological tissues. Of course it is well known
that crystals grow, but perhaps not too obvious how 20 nm mineral spheres
could reproduce. It is still very much a mystery.
I can't help being reminded of perhaps the oddest theory around for the
origin of life, that of Graham Cairns-Smith. Years ago I read his book
Seven Clues to the Origin of Life, which advances the notion that the
first life forms may have been composed entirely of inorganic minerals,
in the form of clay. Clays, which are collections of small mineral
crystals, are able to grow from saturated solutions, and the new material
will copy the existing crystalline structure. Cairns-Smith argued that
this replication-with-variation allowed for a form of natural selection
and brought the possibility of Darwinian evolution among clays.
He then hypothesized that certain clays could evolve the ability to
catalyze organic reactions and increase their reproductive fitness.
This would lead to a hybrid organism, part mineral and part organic.
Finally the organic part got so efficient that the mineral part was
abandoned and pure organic life forms were born.
It is a very speculative theory although as I recall he made a
surprisingly good case in his book. Nevertheless there has never been
any direct evidence in its favor. However, reading about the strange
properties of nanobacteria, where the dispute is whether they are mineral
or organic, I can't help wondering if they could be vestigial Cairns-Smith
organisms: perhaps pure mineral, or perhaps mineral with some associated,
catalyzed organic reactions to aid in reproduction.
There is a great "Nannobacteria Photo Gallery" at
frustrating to see the electromicrographs of these spheres and realize
that we can't just cut them open to see what's inside! In some ways the
world of the very small is as inaccessible as that of the distant stars.
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