80
L. B. SLOBODKIN
restrictions are introduced. Even for the case of uncrossed or noninterlocking feedback loops, the theorem is only valid if the power
source for the feedback loop is contained within the system.
The degree t o which an ecological community can be analogized t o .
an electronic circuit is arguable (see Slobodkin, 1960), but it is clear
that ecological communities are feedback systems of high complexity
in which the power source for the feedback components, even if they
could be physically distinguished in the way an electronic feedback
component can, is almost certainly external t o the system. For ecological communities, it is, therefore, impossible t o make any unequivocal
statement a t all about the relation between steady state conditions and
the rate of entropy production. Obviously net cosmic entropy is increased by the activity of ecological communities, but this is not a
particularly surprising or heuristic conclusion.
Foster, et al., continue with a general analysis of the limits of applicability of Prigogine’s theorem but this is not of immediate ecological
concern except to note that they were unable to find any other
thermodynamic property that could be theoretically demonstrated to
reach either a maximum or minimum when any complex feedback
system comes to a steady state.
It might be noted concurrently that if the mass of an open system
stayed constant, and if the rate of entropy production came t o a minimum, the total entropy of the open system must also come to a minimum. While ecological communities may meet the first condition, we
have no reason t o believe they meet the second. The often repeated
statement that evolution tends to lower the entropy of living organisms
is not clearly demonstrated and is of problematic value.
Therefore, the most interesting theorems of thermodynamics don’t
seem to apply to ecological systems in any direct way. The interest
of translating directly measurable ecological parameters into the
language of thermodynamics is not obvious. Nevertheless, several
authors have attempted this translation and have produced conclusions
which might at first glance be mistaken for empirical generalizations. The
two major recent expositions of the application of thermodynamic theory
to ecology are those of Patten (1959), and Odum and Pinkerton (1955).
Patten quotes the aphorism of Schrodinger (1946) : “What an organism feeds upon is negative entropy. Or, t o put it less paradoxically, the
essential thing in metabolism is that the organism succeeds in freeing
itself from all the entropy it cannot help producing while alive.”
Schrodinger points out, in support of the notion that negative
entropy is what is consumed by organisms, the apparent lack of logic
in metabolism. That is, “Any atom of nitrogen, oxygen, sulphur, em.,
is as good as any other of its kind. What would be gained by exchanging
L. B. SLOBODKIN
restrictions are introduced. Even for the case of uncrossed or noninterlocking feedback loops, the theorem is only valid if the power
source for the feedback loop is contained within the system.
The degree t o which an ecological community can be analogized t o .
an electronic circuit is arguable (see Slobodkin, 1960), but it is clear
that ecological communities are feedback systems of high complexity
in which the power source for the feedback components, even if they
could be physically distinguished in the way an electronic feedback
component can, is almost certainly external t o the system. For ecological communities, it is, therefore, impossible t o make any unequivocal
statement a t all about the relation between steady state conditions and
the rate of entropy production. Obviously net cosmic entropy is increased by the activity of ecological communities, but this is not a
particularly surprising or heuristic conclusion.
Foster, et al., continue with a general analysis of the limits of applicability of Prigogine’s theorem but this is not of immediate ecological
concern except to note that they were unable to find any other
thermodynamic property that could be theoretically demonstrated to
reach either a maximum or minimum when any complex feedback
system comes to a steady state.
It might be noted concurrently that if the mass of an open system
stayed constant, and if the rate of entropy production came t o a minimum, the total entropy of the open system must also come to a minimum. While ecological communities may meet the first condition, we
have no reason t o believe they meet the second. The often repeated
statement that evolution tends to lower the entropy of living organisms
is not clearly demonstrated and is of problematic value.
Therefore, the most interesting theorems of thermodynamics don’t
seem to apply to ecological systems in any direct way. The interest
of translating directly measurable ecological parameters into the
language of thermodynamics is not obvious. Nevertheless, several
authors have attempted this translation and have produced conclusions
which might at first glance be mistaken for empirical generalizations. The
two major recent expositions of the application of thermodynamic theory
to ecology are those of Patten (1959), and Odum and Pinkerton (1955).
Patten quotes the aphorism of Schrodinger (1946) : “What an organism feeds upon is negative entropy. Or, t o put it less paradoxically, the
essential thing in metabolism is that the organism succeeds in freeing
itself from all the entropy it cannot help producing while alive.”
Schrodinger points out, in support of the notion that negative
entropy is what is consumed by organisms, the apparent lack of logic
in metabolism. That is, “Any atom of nitrogen, oxygen, sulphur, em.,
is as good as any other of its kind. What would be gained by exchanging