More to life than power?
The idea behind the maximum power principle was well
expressed by Lotka in 1922:
It has been pointed out by Boltzmann that the
fundamental object of contention in the life
struggle, in the evolution of the organic world
is available energy. In accord with this
observation is the principle that, in the struggle
for existence, the advantage must go to those whose
energy capturing devices are the most efficient in
directing available energy into channels favourable
to the preservation of the species.
- Contribution to the energetics of evolution - Lotka, A. J., 1922
However isn't this a bit of a simplification?
Organisms don't only compete for energy - and other
factors may mean that those with the best energy capture
devices are not - in fact - the most successful.
To give a concrete example, imagine a planet
dominated by two types of microscopic plant life
one with a more efficient sort of chloryphill than
the other - and the other with better capabilities
at generating structural elements.
Just because one species of organism is better at exploiting
the incident solar radiation, that doesn't mean it is
guaranteed victory. What if the structural engineering
feats of its competitor mean that it comes to form
structures that can tower over those of its competitors, and
intercept the light before it reaches them? If that
happens, won't we see a kind of survival of the
tallest - rather than survival of those best at
using the energy.
The short answer to that is "yes" - it is possible
for organisms which are less efficient at consuming
energy to out-compete more efficient competitors.
However, in this example, what is eventually likely
to happen is that organisms with both the efficient form of
chloryphill and good structural engineering
capabilities will arise and come to dominate.
Circumstances where rapid and thorough utilisation of
resources are necessarily subjugated to other
concerns are rather harder to imagine, and it seems
reasonable to hypothesize that such circumstances would be
This is the sort of example that "proves" the rule - by
showing exactly where it breaks down. It doesn't imply
that ecosystems don't behave as though they are maximising
their power throughput - but rather that they don't
necessarily always do so.
The result is a rule rather like the second law of
thermodynamics - one that may be subject to violations
if a system is examined in too much detail - and is best
expressed as a long-term statistical tendency.
Tim Tyler |