living systems and 2nd law of thermo??????

simon sbe at
Tue Sep 26 02:18:41 EST 1995

rray at (ROMAN RAY ) wrote:
>  Living sytems have order.  Why does this not violate the second law
>of thermodynamics?????

It does not violate the second law - this law only applies to *isolated* 
systems - those which can not exchange heat or matter with their 
surroundings. Living cells/organisms are *open* sytems because they 
exchange both heat and matter (nutrients/excreta) with their 

If you do the measurements/calculations on a living system *plus* its 
surroundings, then any decrease in the entropy of the living system (an 
increase in its "order") is more than balanced by an increase of the 
entropy of the surroundings.


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