Natural Science Forum / Biology / Paleontology / February 2005

It's probably a good subject for discussion, but discussing the paper
entails reading it -- a problem for those of us who are a number of
miles and an outrageous parking situation from a decent library.

There is an abstract of the Budd and Jensen paper at
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?holding=npg&cmd=Retrieve&db=PubMed
&list_uids=10881389&dopt=Abstract
for anyone who wants to discuss this.

Is there a more complete summary someplace on the Internet, and if so
would someone care to post a link?

I shouldn't express an opinion on a paper that I haven't read.  But
I'm going to.  I gather from the abstract that Jensen and Budd are
arguing that the actual differentation of MOST modern phyla is
somewhat more recent than current interpretations of the fossil record
suggest.

I can live with that with a caveat.

It is pretty clear that at least four of the comparatively small
number of phyla that paleontologists have traditionally concerned
themselves with -- arthropoda, chordata, echinodermata, and
brachiopoda really do show up in the fossil record virtually
simultaneously and with many (most? all? of their identifying
characteristics in place) .  A fifth -- porifera -- predates them
considerably (but it's not part of bilaterata).  Two other major phyla
-- cnidaria and mollusca -- might postdate or predate the Cambrian
Explosion by a bit, and we may never know which.  Bryozoa and
Graptolites really do show up later.  Other than that, most phyla are
either oddities living on the teeth of Norwegian lobsters or "worms".
The problem with "worms" is that except for teeth (conodonts and
chaetognaths), they don't fossilize well and even when they are
fossilized the characteristics that make them different usually aren't
preserved.

If you think "worms" are important, then Budd and Jensen may well be
dead on.  We don't (and may never) know when, how, or why they
differentiated.

A point.  Notwithstanding that there are lots of Early and PreCambrian
fossils known, the fossil record from those times may be largely
hopeless as far as intelligent interpretation goes.  There are simply
too many forms and too little meaningful information about how they
are interrelated.  It looks to me like systematics with or without
cladistics is about as good as tarot cards if you don't have enough
meangful data to apply it to.  Doesn't mean that there is nothing to
be learned by studying those fossils, just that they are unlikely to
yield much of the information that we'd like to have.

I gather that the problem with Budd and Jensen's paper isn't a problem
with the paper at all.  It is that it has fallen into some sort of
metaphysical debate between Creationist nutcases and anti-creationists
who aren't much better.  These beauties are conducting a raucous
debate about how many intermediate features can dance on the head of a
pin.  As a result if there are intelligent discussions of Budd and
Jensen's thoughts on the Internet or Usenet, they are buried in heaps
of creatonist and anti-creatonist nonsense.