From, Isaac Asimov, The "Threat" of Creationism:

    Creationists have learned enough scientific termiology to use it in their
attempts to disprove evolution.  They do this in numerous ways, but the most
common example, at least in the mail I receive, is the repeated assertion that
the second law of thermodynamics demostrates the evolutionary process to be
impossible.
    In kindergaten terms, the second law of thermodynamics says that all
spontaneous change is in the direction of increasing disorder-that is, in a
"downhill" direction.  There can be no spontatneous buildup of the complex
from the simple, therefore, because that would be moving "uphill."  According
to the creationist argument, since, by the evolutionary process, complex forms
of life evolve from simple forms, that process defies the second law, so
creationism must be true.
    Such an argument implies that the clearly visible fallacy is somehow
invisible to scientists, who must therefore be flying in the face of the
second law through sheer perversity.
    Sceintists, however, do know about the second law and they are not blid.
It's just that an argument based on kindergarten terms is suitable only for
kindergartens.
    To life the argument a notch above the kindergarten level, the second law
of thermodynamics applies to a "closed system"-that is, to a system that does
not gainn energy from without, or lose energy to the outside.  The only true
closed system we know of is the unniverse as a whole.
    Withen a closed system, there are subsystems that can gain complexity
spontaneously, provided there is a greater loss of complexity inn another
interlocking subsystem.  The overall change then is a complexity loss in line
with the dictates of the second law.
    Evolution can proceed and build up the complex from the simple, thus
moving uphill, without violatin the second law, as long as another
interlocking part of the system-the sun, which delivers energy to the earth
continually-moves downhill (as it does) at a much faster rate than evolutio
moves uphill.