Origin of life, thermodynamics #5

Paul Brown (pdb@novell.uidaho.edu)
Sat, 5 Apr 1997 13:24:53 PST8PDT

Thermodynamics, #5. This is the final post of several concerning
why I think thermodynamics poses a problem for the spontaneous origin
of life. I started thinking about this because of posts on the
Sci-Chr home page, and then various posts on this one, including
those between Steve Jones and Pim van Meurs. I don't know if this
will turn out to be entirely correct, but at this point it is what I believe.

I would like to argue that thermodynamics does not present a barrier in some
absolute sense. We're here. There are ways to accomplish the
necessary work. Mechanical work, for example, is accomplished through the use of
machines (such as the piston arrangement). A constraining apparatus,
such as a machine, is a third necessary factor. What we are really
talking about is a way to convert one form of energy into another
taking advantage of an open system.
The "machinery" or apparatus of the cell in a biological system is
able to couple the energy/mass flow through the system to accomplish
chemical work, much the same way a steam or gasoline engine couples
mass and energy flow to mechanical work. To accomplish the desired
type of work, not just any machine will do, but specific machines are
required to accomplish specific tasks. For example, mechanical work
can be used to accomplish chemical work through the use of a
generator coupled to a battery. For living systems, work must be
specific to the function of the cell. Biological systems do this
through chemical machines called enzymes, and through coupling
reactions of high energy to reactions that are not energetically
favorable. But living systems have too many non-spontaneous
reactions to assert that thermodynamics presents no problem for
chemical evolution. One cannot continually make vague appeals to the
increasing entropy of the surroundings at the expense of decreased
entropy of the system. The work must be specified. A plausible
scenario using only naturalistic assumptions must be introduced.

Naturally, chemists, engineers, biochemists, and so on, may design
and build apparatus (machinery, etc.), and supply energy which can
accomplish many of these tasks. Thus, added intelligence may be able
to design a sufficient constraining system to force the reaction in
the desired direction. Of course, for a naturalistic explanation of
the origin of life, chemists aren't around. Neither are the
molecular machines whose origin we are trying to explain. The
problem regarding the origin of life is this: the machines used to
accomplish work and thereby reduce the local entropy in all real
living organisms (the system), exist themselves as reduced entropy
states that do not spontaneously form under any conceived natural
conditions that occur on earth. How does one explain the existence
of the molecular machinery, occurring in a reduced entropy state,
before the existence of the machines used accomplish the work necessary to create
these reduced entropy states? It is probably worth repeating, that
to argue non-spontaneous (+DG) reactions necessary for the origin of
life present a problem, is not to say it can't be done. It does mean
that its highly unlikely to happen on its own, and if a person is
going to say that it does, it is incumbent on that person to tell us
how.

I believe the thermodynamic problem, at least in principle, is
removed upon the formation of some minimum set of machinery capable
of accomplishing the necessary work. This minimum set is present,
for example, in something like a fertilized human egg cell that
turns into someone like you or me. All the necessary machinery and
information to create the reduced entropy state we temporarily enjoy
as our bodies is contained in that single cell.

I agree with many that creationists often over-reach with the 2nd law
argument, wanting to apply this to the entire process of evolution
(when the machinery is present), the fall, and so on. Still, to
ignore thermodynamics is to ignore a problem. "Morowitz has
estimated the increase in the chemical bonding energy as one forms
the bacterium Escherichia coli from simple precursors to be 0.0095
erg, or an average of 0.27 ev/atom for the 2 x 1010 atoms in a single
bacterial cell. This would be thermodynamically equivalent to having
water in your bathtub spontaneously heat up to 360 oC," (Thaxton, et
al., 1984). The feasibility of naturalistic explanations to overcome
this problem may be debatable, but even from only a thermodynamic
point of view, I am not particularly more concerned about the
spontaneous origin of life than I am about being spontaneously fried
in my bathtub. There are good reasons why spontaneous generation
does not happen. Thermodynamics, including the second law, is one of
them.

Ref. Thaxton, C.B., W.L. Bradley, and R.L. Olsen. 1984. The Mystery
of Life's Origin. Philosophical Library, New York.

Regards, Paul
Paul D. Brown
Dept. of PSES, University of Idaho
Moscow, ID 83844