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Information Transmission in Evolution

September 10, 2009

This is an interesting interview with Niles Eldredge of the City University of New York.  It’s a very good account of looking at both the parallels and the differences between biological evolution and the idea of cultural and/or technological evolution.  First off he takes on the issue that in biological evolution we have DNA linking and encoding the information from one generation to the next:

Eldrege notes that the absence of DNA is not an issue; firstly because evolution itself was developed prior to our knowledge of DNA – based on phenotypes (what we can observe).  Second he notes that the transfer of information, while less predictable than in DNA, is absolutely there and is even more dynamic that we find in biological systems.

In both biology and material cultural systems, history is indeed staring you in the face when you look at a wombat or a cornet. But there is no way to divine that history unless you compare a series of objects that you assume a priori are related-more wombats; other marsupials; other mammals, other vertebrates, or a series of cornets. This is the so-called “comparative method”-and owes its beginnings to the nominal father of comparative anatomy, Baron Georges Cuvier.

In the biological realm, you find that while not all wombats are exactly alike, they share a lot of features-more than they do with any other mammalian species. You find they share with other species like koalas and wallabies a reproductive system different than other otherwise putative relatives (like platypuses): there are subgroupings here defined on the basis of shared possession (i.e. within the group) of features not seen in the other subgroups; but the pouched animals share with the placental ones (e.g. rabbits) the presence of three bones in the middle ear-unlike the egg-laying platypus, with one bone there. Yet all three groups have hair.

So you think: hair is more widely distributed in nature than three-bones-in-the middle ear; hair is in animals (platypus) that otherwise lay eggs and have a single middle-ear bone-features that are also found in still other animals lacking hair (reptiles). So we think we see history here: hair evolved before non-egg-laying modes of reproduction; hair defines “mammalia”, while the placenta defines, well, placental mammals. Hypotheses such as these are further tested by addition of new data (for example, gene sequences)-which may or may not agree with notions of history previously derived from comparative anatomy.

For the most part, simple trees of what-is-more-closely-related to-what fall out of this sort of exercise-trees which, as Darwin pointed out-must exist if all organisms have descended from a single common ancestor. This search for history among a series of objects is a mapping exercise of the distribution of characteristics.

The same must be true, in general, in any system that has a history-i.e. some features of a focal object (a cornet, say) expectedly were invented before others-every instrument type is a melange of design ideas of varying age. The circular pattern of three turns in the windway between mouthpiece and valves-the pattern most commonly seen in cornets-was in place before a third valve was added to the original two, and before the modern valve was invented and incorporated onto these instruments. We happen to know this through patents and dated specimens-but it is also apparent simply because two valved cornets with the older valve type, and three-valved cornets with that valve type have this “circular wrap”-indistinguishable from the wrap of modern cornets with modern valves. Same principle.

But right away there are problems: what do you call a 4 ½’ long coil of lip-blown brass tubing furnished with a slide (like a trombone) rather than valves (like a piston valved trumpet, or cornet)? Is it a soprano trombone, or a slide trumpet/cornet? The answer is a resounding “Yes.” Depending upon context, such instruments have been built and called all of these names-both before and after the invention of valves.

The key difference is that biological systems predominantly have “vertical” transmission of genetically-ensconced information (meaning parents to offspring). To be sure, there are some groups where hybridization (lateral blending of two species) occurs; remotely related bacteria are also famous for being able to exchange genetic information. But the neatness of evolutionary trees in general in biological systems stems from the compartmentalisation of information within historical lineages.

Not so in material cultural systems-where horizontal transfer is rife-and arguably the more important dynamic. Makers copy each other, and patents affording only fleeting protection. Thus, instead of neatly bifurcating trees, you would predict to find what is best described as “networks”-consisting of an historical signal of what came before what, obscured often to the point of undetectability by this lateral transfer of subsequent ideas.

But unlike nature (including the fossil record), material cultural systems of the modern era characteristically leave a paper trail-patents, advertising, sometimes even serial numbers and records of the dates they represent that allow an independent assessment of history-one against which the results of a comparative study can be compared. Unsurprisingly, it is VERY good to have this extra information!

Now if you start to look at source code (a virtual paper trail?) as analogous to DNA, then not only will we see the more predicable transfer of information in a more formal sense, but a layer on-top of this of cultural information conveyance (I’m calling the meme-layer) that is dynamic.

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