Saturday, January 17, 2009

Biomimicry of evo-devo patterns.

The evo-devo (evolutionary developmental biology) idea is that organisms have basic developmental core processes (a toolbox) that are regulated during development by other genes. Thus basic mechanisms such as development into segments can be regulated to produce few-segmented organisms such as insects or many segmented organisms such as snakes.

There is a surprising analogy in the UNIX (and thus LINUX) operating system design philosophy: "Rule of Separation: Separate policy from mechanism; separate interfaces from engines." The short version is "mechanism, not policy".

The X windows system, written about 25 years ago, made heavy use of this design principle. X provided the mechanism for user interfaces that did all the hard work of drawing and reacting to user input in a very concise and general way. Specific user interfaces such as Motif and OpenLook (that looked very different) could then be created just by controlling the use of X mechanisms.

A more recent development (10 years) exploiting this design principle has been the addition of cascading style sheets to HTML. The underlying HTML of a web page can be displayed in radically different ways depending on the style sheets applied to it. (For explanation and some amazing variations, see Zen Garden.)

Another possible example of this biomimicry is the Constitution of the United States, as I explain in Mechanism, Not Policy: Creation Of The Second Invisible Hand. This one predates modern evo-devo ideas by quite a bit, but is my own (possibly crank) interpretation.

The evolution (in the sense of change over time by modification) is obvious in all three of these examples.

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