living systems and 2nd law of thermo??????
sbe at biochem.usyd.edu.au
Tue Sep 26 02:09:42 EST 1995
rray at ix.netcom.com (ROMAN RAY ) wrote:
> Living sytems have order. Why does this not violate the second law
Because they are *open* systems (ie they can exchange both matter
(nutrients, excreta) and heat with their surroundings). Any increase in
the *order* (or decrease in entropy) of a living system is more than
balanced by a decrease in order (or increase in entropy) of its
surroundings. The second law of thermodynamics only applies to
*isolated* systems (those which can nor exchange matter and heat with
their surroundings. Thus, if you you consider a living system *and* its
surroundings as an isolated system, then deltaS for this will be
positive for any spontaneous change.
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