[Phys-L] Re: Entropy

[anngeorg at PACBELL.NET (Bernard Cleyet)]

this might explain so many silent genes.

bc, only one undergrad. course too many years ago; simple thermo. NOT
stat. mech., and GOOGLER:

BIOPHYSICS 354
... the reversible process, are of special importance in thermodynamics, ...
For all spontaneous processes, the change in state of the system must
have a ...
www.life.uiuc.edu/crofts/bioph354/thermo_lesson.html - 9k - Aug 11, 2005
- Cached - Similar pages

http://www.life.uiuc.edu/crofts/bioph354/thermo_lesson.html


The second law of thermodynamics expresses the phenomenon that the
universe tends towards maximum disorder, or, in other words: the
direction of all spontaneous processes is such as to increase the
entropy of a system plus its surroundings ( delta S is positive). It
introduces the quantity S, the entropy to describe the state of a
system. The entropy is a measure for a system's degree of disorder. It
increases with increasing disorder.For a system at equilibrium is the
entropy of the system plus its surroundings maximal and delta S is zero.

The fact that the entropy of a system may decrease during partial
processes is not inconsistent with this law. It is normal as long as the
entropy of the surroundings increase in at least the same amount.

This slightly abstract law is maybe best explained with the example of
the phenomenon life with all its aspects like growth, reproduction and
evolution. Everybody knows that cells, cell assemblies and organisms are
complex structures with processes much more complex than those taking
place in the inanimate nature. Every organism represents an open system,
i.e. it has continuously to take up energy from its surroundings to keep
up its degree of order and the integrity of its structures. All its
processes are irreversible. Organisms are thus always in a state of flow
(a steady state), never at a stable equilibrium. Moreover is it
generally known that most of this energy is made available by
photosynthesis, which again is dependent on sun energy. The energy
transformation (matter to energy) taking place at the sun's surface
causes a large positive delta S. A small part of it is invested into the
generation and perseverance of structures at the earth and the delta S
of the sun is diminished only by this insignificant portion, but the
overall entropy of sun plus organisms on earth still increases.

http://www.biologie.uni-hamburg.de/b-online/e18/18a.htm


bc, again not worried, if the preceding is "true".  Who also awaits the
demolishment by the experts on this list.






Jim Green wrote:

> The following was quoted in this morning's paper.  What is your reaction to
> it?  How would you answer a student's concern about it.
>
> "Specifically, the second law [of thermodynamics] tells us that increasing
> complexity is a natural consequence of all spontaneous processes, that is,
> that natural systems tend to become more complex with time."
>
> Jim
>
>
>
> Jim Green
> mailto:JMGreen@sisna.com
> http://users.sisna.com/jmgreen