Explanations and morphology

[Richard.Zander at MOBOT.ORG]

I was just thinking about explanations, particularly J. Grehan's discounting
them. Sure, theory is the basis of science, but John is right that
explanations can be rather empty.

Try this: according to theory, molecular systematics depends on (mostly)
neutral mutations, so it is an independent check on morphological
systematics, which reflects massive convergence.

Well, if morphological systematics is so twisted up by having too few
traits, and these being commonly convergent so as to mask true phylogeny,
then why do molecular and morphological results match as well as they do?
Convergence of morphology is identified ONLY when there is a mismatch of
molecular and morphological results. Massive convergence over time should
practically randomize morphological cladograms (I'm exaggerating for effect,
right?).

I might offer the idea that molecular and morphological results are as
similar as they are because molecular traits, even the apparently non-coding
sites, are affected to an important extent by the same evolutionary
pressures as is morphology. There is considerable theory that in fact
supports evolutionary pressure on synonymous codons (codon bias),
regulatory, promoter and enhancer sequences, tandem repeats that act as fine
tuners for cis-regulation, and like that. Thus, not only is molecular data
not independent of morphological, but "total evidence" that lumps all data
then analyzes it is chock full of convergence responses to environmental
(extracellular and intracellular) selection pressures, much of which is
reciprocally supportive.

That's why the explanation that morphology can be discounted as replete with
convergence and molecular analysis is not is wrong though it sounds good and
wouldn't it be nice if it were true.