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From: chi9@quads.uchicago.edu (Lucius Chiaraviglio)
Newsgroups: sci.space,sci.bio
Subject: Re: Theory for Life
Summary: Several instances of non sequitur
Message-ID: <1990Oct27.045445.28533@midway.uchicago.edu>
Date: 27 Oct 90 04:54:45 GMT
References: <1050400042@cdp>
Sender: news@midway.uchicago.edu (News Administrator)
Organization: Department of Biology at University of Chicago
Lines: 125

In article <1050400042@cdp> dyurman@cdp.UUCP writes:
>This is a reply to a posting from Daniel Mocsny on the subject
>of THEORIES NEEDED FOR LIFE.  I would like to add a couple of
>points.
>
>1st: in order to develop technology, the creature must have the
>ability to store information external to its brain, or
>equivalent, in a nonperishable form.  While "pixel-addressable
>pigment cells" is a wonderfully creative idea, an alphabet and
>printing are more useful.

	Actually, information storage does not absolutely have to be external,
as long as it is sufficiently non-perishable to support the development of a
technological civilization.

>2nd: the creature must be a predator, otherwise it's species will
>spend too much time avoiding being something else's supper.  This
>will not leave any time for rocketry.

	Does not follow.  Perhaps avoiding being someone else's supper might
be a strong selection for intelligence and the development of technology (to
be used against whomever was trying to make supper out of the technological
species).  This doesn't seem to have been the primary selective force for the
development of intelligence and technology on Earth, but that doesn't mean it
couldn't be.

>                                       It must be at or very near
>the top of the trophic web not only for its niche, but also for
>the planet.

	Why?  See above.

>             Given the interstellar nature of DNA building
>blocks, its meals must be the products of concentrated protien
>and other nutrients from intermediate steps in the food chain.

	Silicate grains seem to be a pretty common interstellar material.
Maybe these are someone's building blocks.  Note:  I am NOT talking about
using silicon as an analog of carbon.  It has been shown that that will not
work.  What I am talking about is the use of polysilicates and their
derivatives (silicones, which are very stable, for instance) as a basis for
building blocks.  Also, some uses of organic chemistry to form things other
than amino acids and nucleic acids are a possibility.

	An aside here:  not only do people trying to imagine life on other
worlds have the problem of their imagination tending to be channeled towards
things such as exist on Earth, their imagination tends to be channeled towards
the very small subset of Earth life that they know of.  The great majority of
science fiction and serious science (-: well, they try anyway :-) imagination
of life on other worlds imagines things homologous to what most of us see:
plants, animals eating either plant or animal matter, and occasionally fungi.
Mention of microorganisms is generally restricted to diseases, if they are
mentioned at all -- and then often the more serious thought assumes that none
of these would be able to eat anything from Earth, which is likely wrong given
the extraordinary variety of substances that microorganisms can metabolize --
I mean, we really have to do a considerable amount of work to make completely
unmetabolizable organic compounds, and a significant number of inorganic
compounds can serve as food for various organisms.  Even among life using only
biochemical pathways found on Earth (almost certainly less diverse than the
biochemical pathways which actually exist on Earth) a staggering variety of
ways to live exists, and an environment different from that which we live in
(but similar to some environments found on Earth) could conceivably select for
a planet-dominating organism very different from us and the organisms we know
with respect to the TYPE of food chain it is in, let alone the position.  Such
organisms may have not developed high-order multicellularity and/or
intelligence on Earth simply because their environments are too restricted.
(Actually, one possible such environment we do not know the nature of is the
hydrothermal environment beneath the surface of the mid-ocean ridges, which
take up a substantial fraction of the surface area of our planet -- I forgot
what the number is, but I am pretty sure it is up in the 10% - 20% range.
Maybe a Lovecraftian mass of slime is brooding down there, waiting. . . :-))

>3rd: assuming carbon-based life, sensory organs must be seated as
>close as possible to the brain in order to provide the shortest
>possible response time between reception of input and reaction to
>it.  See predator concept above.

	For some environments, a factor other than response time might
dominate the placement of sensors relative to the brain.  For example, imagine
an organism in a very treacherous and abusive environment.  If the organism
could regenerate parts, it could deal with repeated loss of sensors, but even
with regeneration major brain damage would be majorly bad news for retaining
memories needed for civilization.  Therefore, it would make sense to either
have the brain as far away as practical (and behind as much shielding as
practical) from all of the common types of abuse, or to have a distributed
redundant form of memory storage so that even a drastically mangled organism
would have a good chance of containing at least one complete copy of its
memories.

>5th: from what we know of the processing power of our own brains,
>there is a trade off of energy expended between physical
>coordination or limbs and manipulation of abstract concepts.
>This suggests that a creature with four arms or eight elephant
>like trunks might spend all its time worrying about where the
>parts of its body were and what to do with them, and less time
>about its future as a life form or the meaning thereof.

	Our own brains should not be taken as ultimate examples -- that is, we
should not assume that they represent the full range of what can be done with
a nervous system.  To be sure, an organism with more limbs would probably need
a somewhat bigger brain to use them all as well as an organism with fewer
limbs and equal intelligence and equal efficiency of utilization of brain
weight and space, but this does not mean that that is impossible.  Also, no
reason exists why a multi-limbed organism could not evolve so as to be able to
choose at will whether to distribute its motor coordination to all limbs or
concentrate most of it on a few so that less brain weight would be required to
control them.  As a matter of fact, we can do this to some extent.

>6th: the creature must have the ability to develop abstract
>thinking [see #1 above on storage of information] else it will
>fail to develop methods for organizing information, and thus fail
>to develop technology.  This suggests a protective shell of some
>kind for the brain or equivalent, else the creature will never
>have its mental abilities survive long enough to get the
>abstractions built much less communicated.  [. . .]

	A protective shell would certainly be useful for this, but not the
only means of making memory non-perishable.  Having distributed redundant
memory would also work; if suitable high-data-rate communication were a
biological feature of an organism, memory and even thought could be
distributed over multiple physical individuals, so that logical individuals
need not correspond to physical individuals (-: brains like a Sequent :-).

--
|   Lucius Chiaraviglio    |    Internet:  chi9@midway.uchicago.edu