Sunday, March 12, 2006
An Internal Evolutionary Mechanism and 'Direction in Evolution': Preliminary Notes
A TalkOrigins archive page entitled "Evolution and Philosophy: Is There Progress and Direction in Evolution?" begins:
One of the more common misconceptions, with a history long before Darwin, is that evolution is progressive; that things get more complex and perfect in some way. In fact, this view is attributed more to social and religious attitudes of 18th and 19th century European culture than to any evidence. It was a given that things are getting better and better, every way, every day. This persisted until long after Darwinism, until the middle of this century (e.g., Teilhard de Chardin). Even Darwin was ambiguous about it, talking on occasion about 'perfection' as a result of selection.It is implicit in proposing an internal evolutionary mechanism based on homeostasis that it must 'operate' in the same way at either end of the current evolutionary spectrum. The purpose of the following notes is to briefly demonstrate why the proposed mechanism is not 'directional' and/or imbued with a 'progressive' intent.
At the time of the 'modern synthesis' [note 9] in the 1940s, the notion of progress was quietly dropped, with a few exceptions like Dobzhansky and Huxley within the synthesis, and Schindewolf and Goldschmidt outside it. Of course, heterodox writers (usually not biologists) like Teilhard and Koestler remained progressionists long after this. But by the 1970s, progress had been abandoned by working biologists.
Recently, the issue has resurfaced, shorn of the mysticism of earlier debates. Biologist J.T. Bonner argued that there was a rise in complexity of organisms over the long term , and others were arguing for a form of local progress under the terms 'arms race' [Dawkins and Krebs 1979] and 'escalation' [Vermeij 1987]. Gould  felt so strongly about it he was moved to deny that, at least since the Cambrian explosion, there has been any progress at
The Main Blog post The Internal Evolutionary Mechanism: Basic Concept describes a localized 'area of natural equilibrium' (AONE) at the apex/center of an homeostatic hierarchy along with the following flowchart producing the fibonacci series:
Consider an organism 'y' whose AONE is at equilibrium, ie x = 1. Without specifying why or how at this point (except to say the existing thresholds of the AONE have to be exceeded) x begins to increase - although it's not a runaway process: for the sake of argument assume x increases by '1' in this generation, another '1' in that, etc., etc.. During this period there is no discernable change in the Output "y" box.
To recap: The fibonacci series begins "0, 1, 1, 2 ,3, 5" and each subsequent number can be formed by adding the two preceeding numbers together, eg 2 + 3 = 5, 3 + 5 = 8, 5 + 8 = 13 (etc.).
If the larger of two sucessive fibonacci numbers is divided by the smaller then a number is obtained which increasingly approximates to the 'golden ratio' or 'golden number': 1.6180339887498948482....
The flowchart opposite will generate the fibonacci series endlessly.
For simplicity it ignores the first zero, and rather than 'seeding' the program and adding succesive fibonacci numbers together, it generates the numbers via testing the ratio of 'x over y' against phi (where phi equals the golden number/ratio).
'y' is the fibonacci number produced, 'x' the incremental count. 'F' is required to test whether the 'x over y' ratio is closer to the golden ratio when x/y is above or below it.
NB I hope the maths are correct - please email any comments (and I would like help/advice in developing this further).
When x/y exceeds phi then integration begins over 'n' generations (initially fast but then tapering off - although not apparent in this very basic model!) which may produce changes in the Output "y" box.
When integration is complete there is a new "y" ("y2") whose localized area of equilbrium has been restored to the initial state (ie x = 1).
If the new thresholds of y2 are exceeded then the process may begin again (and may stop at any point, even 'lose' - through the same modus operandi - any increments of x).
The flowchart produces the fibonacci series 1, 1, 2, 3 ,5... ...55, 89, 144 (etc.)
From an external viewpoint we are able to see the pattern and can predict what the next fibonacci number generated will be. Internally, however, the algorithm works the same way in every instance.
Equating the above fibonacci numbers to organisms: the transition from organism 2 to organism 3 simply reflects the internal 'resetting' of the AONE to its initial state - there's no intention/direction/progression towards ultimately 'producing' organisms 144, 233, etc..
Hope the above makes sense, it's rather late and I bet I groan when I read it through in the morning (if I do then I'll amend this accordingly so do come back!).