Complexity, Self organisation and evolution
In previous posts on the subject of the Evolution/ Creation debate I have as an aside made some remarks to the effect that I suspected that evolution through natural selection might be connected to some more fundamental properties of the Universe - in particular thermodynamics and entropy. I claim no great knowledge about these things but it has always struck me that life as a process has some interesting connections to these issues.
I wasn't aware at that time that there has actually been some studies and speculation in this field. I came across an interesting article which highlighted some research in the field of computational evolution.
The second law of Thermodynamics suggests that in a closed system the system will move to Thermodynamic equilibrium ( move towards maximum Entropy) and will be in its maximum state of disorder. However the real world at the local scale often does not function locally as though it is a closed system and we often see order emerging from disorder - crystallisation, snowflakes etc etc.
An article in wiredscience discusses some interesting work by Guy Hoelzer which involved computational modeling of population genetics. In his own words his approach;
..involves a different approach from traditional mathematical modeling: it allows us to spread a population across a large [and uniform] space in the computer model. One thing I find is that as mutation occurs in the system, it drives genetic divergences in a spatially localized way. I get spacial self-organization. One sub-species dominates in one place; a different sub-species in another place. If I allow genetic incompatibilities to evolve through mutation, we get speciation. Speciation is a process of self-organisation of the gene pool; in this case, it's not driven by adaptation to environmental conditions.
In other words he sees evidence of the "computational organism" beginning to show evidence of speciation even without selective pressures from the environment or from interaction with other species. This begins to sound more like an emergent self organising feature of a complex system rather than the traditional Darwinian process of natural selection.
It is interesting to speculate if life may have at it's core some fundamental self-organising and diversifying principles of this nature which are then magnified by natural selective processes. Another paper at wired science makes a broader case for a further revision of current evolutionary thinking using concepts of complexity theory.
( Note to readers - you will be disappointed if you think that any of this lends weight to Intelligent Design)
Update: Here's another article about the issues of complexity
5 comments:
Just regarding the second law and closed systems, and, well, mechanics being my specialty ...
The classical form of the second law is formulated with respect to a closed system. The more generalized and practical one used in engineering is for open systems, and includes a surface flux term to take into account the effects of a system not being closed to the surroundings. If the surface flux term is zero, than it reduces to the classical closed system form.
If we take are control volume to be a sphere centered about the solar system, and then increase the radius and look at what happens to the terms, then the surface flux tends to become negligible compared to everything else and the effect is nearly identical as for a closed system. Thus, the argument against the second law - that it is only valid for a closed system - is basically a technicality.
I make no claims to understand all the theoretical background in respect of the different uses of the concept of Entropy and the Second Law. ( I gather there is some debate also over whether Entropy is fundamental or derived)
However given the little that I know it interests me because at first sight Life seems to run "against the grain" in the sense that it constructs order from disorder by harnessing external energy.
Clearly no real life system can be truly closed because, trivially one could always take a larger scale frame of reference and then consider this to provide the external environment to the system under consideration.
I think when we are considering life on this planet it is clear that the system operates, at this scale and on the timescales within which living things operate, as an open system.
The Earth is an open system in respect of the energy received from the Sun - from which ultimately life takes energy in order to produce complexity. (Ignoring chemotropes - life that uses purely chemical sources of energy.)
What interests me is that we see other examples of local systems producing order from disorder ( snowflakes etc) although to do so there clearly has to be an increase in disorder elsewhere in the system. These examples of "spontaneous" organisation interest me because it shows that given basic physical laws and chemical interactions localised complexity can arise.
This gets me wondering if this same process somehow underlies life and that natural selection then acts to further refine that complexity in terms of it's fitness to reproduce in that system.
I saw a recent documentary of a mine ,in the Swiss Alps I think it was, where they had uncovered a chamber filled with gypsum crsytals metres long and wide.
Clearly such conditions would only probably have just been right to produce such an event perhaps once or twice in the Earths history. The conditions clearly had to be just right to allow such localised complexity to develop.
I suspect that Biogenesis is like that - the localised conditions must be just right but that if they are then some self-organising process allows complexity to develop.
I must read up on all this.
By the way I am currently reading "The Road to Reality - a Complete guide to the laws of the Universe" by Roger Penrose. My Maths is rusty but I am gradually ploughing my way through it. ( Its over 1,000 pages so not a one night read!) Have you read it?
I read one of his previous books "The Emperors new Mind" which essentially, if I recall correctly, culminated in him developing an argument that Quantum effects in certain cell structures may be responsible for "free will".
Wow, 1,000 pages on the laws of the universe! Good luck on completing it. I have a few thousand pages awaiting me already, so it probably won't end up on the reading list soon.
We have bifurcation theory in mechanics which is related to the formation of different species in the form that the article seems to be using. The mathematics comes in useful for constructing buildings, but also explains why you can't crush a beer can the same way twice in a row! Some of the properties can be quite fascinating.
Reading some stuff on fractals and Chaos theory a long time ago I think I recall something that was related to bifurcation theory - is that so?
It seems to me that there is a relationship between fractals and Chaos theory on the one hand and bifurcation on the other, but I must admit that I haven't really gotten too serious about the mathematics. It doesn't directly impact my job, so I try to know just enough in case I run across a situation where it might be useful and I need to dig further.
Post a Comment