[Taxacom] On pattern and structure

Mon May 23 16:25:20 CDT 2011

Ah, excellent, Jason. Yes, phylogenetic is structuralism. The "phylogeny" is the problem. Take a molecular phylogeny. It isn't a phylogeny, it is a rather precise assessment of present-day relationships of exemplars. The present-day relationship of exemplars is not a fundamental structure in nature (i.e., a structuralist pattern), it approximates a phylogeny only to the extent that it estimates genetic continuity and branching order. Speciation is not estimated, and there are artifacts like paraphyly and phylogenetic polyphyly. 

It is not fundamental because morphological cladograms are rejected and all morphological data are simply mapped to the molecular cladogram (i.e., no theory is presented on why they don't match, although you can read allusions to convergence and incomplete lineage sorting). There is no recognition of macroevolution, which is fundamental. Patterns of macroevolution as devised from all relevant data should be that fundamental pattern on which one can analytically map data that are dependent, but we get only microevolution of traits mapped on a molecular cladogram, with no allowing for the fact that about 63% of extant taxa have extant ancestors. 

Let's take the long-suffering polar bear and two molecular brown bear lineages as an example. The evolutionary theory and fundamental pattern is actually an explanation of all data, the polar bear came from one of the brown bear lineages, and Dollo evaluation supports this. The molecular cladogram ((polarbear,brownbear1)brownbear2)... is not a hypothesis, it is a fact. And there is no explanation.

I'm reading a fine book by Morris Kline, Mathematics and the Search for Knowledge. In one chapter he points out that mathematics is totally fundamental in physics. In fact, in electromagnetics, we have a number of fundamental formulae that describe and predict electromagnetic phenomena. But we don't have ANY idea of what it is that propagates a force at a distance like gravity, or what constitutes magnetic field lines, or what is vibrating in wave theory, like what moves in a radio signal. Kline asserts that even so, the science based on mathematics is stupendous, and causal, essential, mechanical knowledge, though absent, has not proved important. 

Well, okay, and the detailed and precise phylogenies of molecular taxonomy are indeed immensely mathematical, but these patterns are NOT mathematical formulae such as there are in physics. Such phylogenies conflict with morphological phylogenies (explanations are eschewed in structuralism), and internally are inconsistent in evincing paraphyly and phylogenetic polyphyly of what are clearly one taxon (in most cases, IMO). 

You may well infer a macroevolutionary scenario from the polar bear, brown bear molecular analysis, and some may not, but my beef is with the phylogenetic classification that results: namely, lumping the polar bear with the brown bear, or recognizing three taxa at the same rank, two of them cryptic and silly. Taxa without names, or those lost among multiple cryptic taxa, cannot be part of a biodiversity analysis, or be conserved.

It may be that problems like the paraphyly of the brown bear, and the portulacca family, will be presented with work-arounds, but there are myriad major groups that have been lumped because recognition requires formal reflection of macroevolution in classification. In my own group of expertise, three families have been lumped into a fourth larger family, Pottiaceae, with no explanation other than that they are nested. There are five huge families also nested but near the base of the Pottiaceae, and phylogeneticists don't have the nerve yet to lump them, but I'm not waiting until they do so to complain about it. If systematists of good will say nothing, now, structuralism will prevail. 

R.

_______________________
Richard H. Zander
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166 U.S.A.
richard.zander at mobot.org

________________________________

From: taxacom-bounces at mailman.nhm.ku.edu on behalf of Jason Mate
Sent: Mon 5/23/2011 2:37 PM
To: Taxacom
Subject: [Taxacom] On pattern and structure

" The phylogeny provides the structure on to which organise the distributional data." This is structuralism. Why can't both pattern and distributional data be explained by a theory that accounts for both? Why relegate distributional data to a pattern. That pattern is ONLY of present-day relationships of exemplars, which needs itself explaining given the inconsistencies (paraphyly) and contradictions (versus morphological cladograms of same taxa). Structuralism is a quick fix based on the impressive precision of measuring present-day relationships, but does not develop a scientific theory.

Even the word "estimation" is loaded. In statistics, we "estimate" when no hypothesis is available. No hypothesis? No previously postulated evolutionary theory? None?"

It is structuralism. I make the assumption that the distribution of taxa is a property of said taxa and can be studied like other essential properties. I make the assumption that the totality of the species´ phenotype determines, to a point, its ecological distribution. As such the phylogeny allows me to arrange the data in such a way that I can make inferences. But just because I have a phylogeny adorned with data I don´t have an explanation. It is an analytical method not a theory. You go in with a hypothesis (I´d prefer to call it a hunch), you gather your data, you analyse it and see if the inferences derived from the analysis refute or support your hypothesis. As for prexisting theories I only go in with Occam´s razor. It is the lesser of all evils.

Regarding the word estimate, please be charitable, I mean that the phylogeny is an estimate. I can´t know if its true, no matter how well it helps me explain the data so I assume it is a valid estimate. Future data may very well prove my wrong.

Best

Jason

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