The Tree of Life

October 11, 2009 by Dr. Mc.

Recently I cited the “tree of life” diagrams of Talking Squid in discussing assumptions of evolution. There they have done a good job of explaining past and current tree metaphors from an evolutionist point of view. I’d like to add a few comments to round out the value of the concept.
To begin, Talking Squid does not say, but one could take from the wording, that Darwin invented the tree concept for representing a common origin of all life. In fact we have a tree drawn by Porphyry (234-305 AD) in his introduction to Aristotle’s Categories. It was his graphic representation of what he had developed from Aristotle’s words, and it has been reworked by many over the centuries, including evolutionists seeking a pattern for life’s diversity. More likely Darwin’s drawing was his attempt to flesh out the concept he had been given with organisms he knew. What was new, as Talking Squid points out, is that Darwin included dead ends, a fundamental part of his natural selection concept.
But the tree concept is quite natural (no pun intended) when one begins categorizing anything. Take for example the rocks in my back yard. I can categorize them by type of material of which they are made, resulting in purer constancies being arranged around the edge (farther apart) and less distinct ones being toward the middle (and closer together). If I categorize them by shape, the same will happen, with round in the middle and all manner of shapes branching off at the edges. Whenever there are a variety of features to be considered (whether they be among organisms, sports equipment, or casseroles), distinct features become branches and commonalities become trunks. If you add the assumption that whatever-they-are evolved from each other, then a tree of origins can be easily had, at least at a tersery glance. Here is another difference between Darwin and many other uses of the Tree of Porphyry. Darwin was not seeking a metaphor. He was seeking real origins. Here I part with Talking Squid: the Tree of Life is not a metaphor to an evolutionist, if they in fact are seeking and believing in real, common origins.
If the categories of whatever didn’t actually evolve from each other, then the devil will be in the details. A closer look at the featureless (impure) rocks in my backyard will reveal that the ones with least distinct features actually have more variety in internal elements.
Interestingly enough, the same thing happens when one attempts to categorize life, except that the devil is not only complexity, but also differentiation. This is easily seen in at least three ways:
First, we have learned that small does not always mean less complex, as Aristotle had supposed when he first posited spontaneous generation. Single-celled organisms are still cells, complete with DNA, cell walls, etc., except they are often capable of more functions than cells of “higher” life forms, such as across-species transfer of DNA components.
Second, features can be found in common when common ancestry is impossible. One well-known example is the octopus, which is a mollusk with an eye quite similar to that of a human’s, except it works better than ours in filtered light. This is why Doolittle’s “tree of life” looks more like a banyan tree, which by the way, has multiple trunks only because it drops them DOWN from branches, not the other way around.
Third, on the most fundamental levels organisms are not more similar. They are more different. Archeans (archi-bacteria) are not just simple bacteria, they have an entirely different DNA language for reproduction than do bacteria. Biologically speaking, archeans are more different from bacteria than are you, the reader, from yeast.
The implications are pretty clear that where life is concerned common origin is an imposed concept on a natural phenomenon. The difficulty in accepting this would seem to stem from the requirement that there be no designer. It is too suggestive that it could be not just a designer but the Designer, even though ID never goes there.

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