The Origin of Life

Bright light

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 rare.

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 | Contact |