Re: [asa] Dawkins on the fossil record

From: David Campbell <pleuronaia@gmail.com>
Date: Wed Dec 02 2009 - 10:51:06 EST

Returning to the original question: There are assorted cases where,
for fairly obvious reasons in the geologic context, a fossil is
seemingly in too old a position. These include association with holes
of various sorts (perhaps the most famous being the Bernissart
Iguanodons, unearthed by mining of Carboniferous coal-the dinosaurs
fell into what was a hole in the early Cretaceous; I think I recall
mention of a mosasaur skull seemingly early but closely associated
with the Wetumpka impact crater; on a small scale most sedimentary
strata have burrows coming down from the layer above),
misidentification of strata (like Walcott's late 1800's report of
Carboniferous Physa, unfortunately still perpetuated in some general
references even though the layer was reidentified as a Cretaceous
outlier in the 1930's, or the examples of various geologists who have
proposed an incorrect stratigraphic model and defended it through
vigorous repetition rather than revising it according to the
evidence), overturned beds as already mentioned, and contamination
(e.g., drilling a core can mix things down from the top of the core;
bioturbation). Additionally, the antievolutionary literature
sometimes invokes as "anomalous" the discovery of related but more
primitive forms in older layers. Similarly, purported or real gaps in
the stratigraphic record of a particular type of fossil have been
invoked at least since the days of George McCready Price (not sure
offhand which edition I have, but his choice of mollusks for his
example meant that I immediately knew that things he said were missing
had been found and well-publicized over fifty years earlier). Upon
examination, real gaps in the known fossil record typically associate
with organisms that are a) poorly studied, at least systematically b)
low in diagnostic durable hard parts or c) inhabitants of bad places
to get fossilized and found (deep oceans, upland areas, rivers, etc.)

However, I know of no case where there is anything in the fossil
record that poses a valid challenge to evolution.

To somewhat agree with Mike and disagree with Kuhn, I would say that
the discovery of a clearly evolutionarily anomalous fossil would
suggest that the particular organism required some other explanation,
but evolution would remain quite useful as a widespread pattern.
Antievolutionary arguments characteristically assume that a single
anomaly justifies throwing out evolution altogether, a view bolstered
by rhetoric like Dawkins'. The same error can be found on the other
side, e.g. this ID argument is bad, therefore every aspect of ID can
be dismissed or global flood models A-D are scientifically untenable,
therefore Genesis is fiction. Perhaps a better question than "what
would disprove evolution?" would be "imagining a planet where life
arose and diversified by some other means than evolution, what might
non-evolved life look like?"

There is some room for charges of circularity, in that many strata are
dated primarily on the basis of what fossils they contain. However,
the pattern holds across fossils that differ in their ecologial,
escape, and hydrodynamic/aereodynamic properties. Also, where
preservation and research funding permit, the paleontological dates
are corroborated with a wide range of other techniques, such as
radiometric dates, stable isotope patterns, Milankovitch cycles,
magnetic reversals, geologic event markers (impacts, volcanoes),
stratigraphic patterns, etc.

-- 
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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Received on Wed Dec 2 10:51:53 2009

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