K> Let's look at this a little more deeply.
K> As you wrote:
S> 1. The distribution of brachiopods vs. bivalve molluscs in the
S> stratigraphic record. There is little difference between these
S> two groups in terms of hydraulic sorting or ability to escape
S> rising flood waters. How do you explain the observable fact
S> that brachiopods are extremely numerous and diverse in Paleozoic
S> strata while becoming much more limited in range and diversity
S> after the Permian extinction while bivalves show the opposite
S> pattern? How do you explain the appearance worldwide of certain
S> brachiopods, for example, which only occur in, say, Devonian
S> strata (I can look up some specific species if you like).
K> This would be a problem hydrologic sorting or ability to escape rising
K> flood waters were the only factors influencing the order of fossils.
K> Another probable factor is original distribution. We don't know the
K> original distributions, but do know that brachiopods and mollusks are not
K> equally distributed today. They were not necessarily equally distributed
K> in the past.
S> Worrying about the original distribution of brachiopods and molluscs
S> doesn't help you.
K> Well, I'm not worried about it, but I notice that if the oceans today were
K> inundated with sediments and fossils were formed, we would have many
K> mollusks in most areas, and only a few brachiopods (with more mollusks) in
K> a few other areas. That is different, almost opposite from the Paleozoic
K> fossil proportions and distributions, but it illustrates how distribution
K> of living forms can influence distribution of fossil forms.
Your claim is apparently that the flood preferentially killed brachiopods
because they lived in areas or environments which were more affected by the flood.
Anyone studying invertebrate paleontology knows that Paleozoic brachiopods are
extremely common in Paleozoic rocks all around the world and these sedimentary
rocks formed in a wide variety of environments (including areas where bivalves
are common today). Those two observable facts show your model to simply be
incorrect.
S> The difference in number and diversity between brachiopods
S> and bivalves in Paleozoic vs. Mesozoic/Cenozoic rocks are worldwide. The
S> mainstream science explanation is that brachiopods were more abundant and
S> diverse during the Paleozoic Era and greatly declined in number and diversity
S> after the Permian extinction event while bivalves were more rare during the
S> Paleozic but took off and become very numerous and diverse after most of the
S> brachiopod species died off. The flood model is what?
K> That brachiopods (Lingulids, Acrotretids, Orthids, etc.) were abundant in
K> preflood seafloor communities with trilobites etc. and, like trilobites,
K> were massively buried during the onset of sedimentation (Cambrian). While
K> some (Orthids, Rhynchonellids, Spiriferids, etc.) may have been pushed
K> upward by the force of the initial currents (turbidity currents), they were
K> nevertheless soon buried (in Ordovician, Silurian, Devonian, etc. layers).
K> Few (but some, especially Rhynchonellids and Terebratulids) managed to
K> survive beyond the Permian sedimentation. Mollusks, by contrast, were
K> less abundant on the preflood seafloor, some living in the water column
K> (Nautilids and Ammonites), or on land (Pulmonata), and very possibly in
K> root masses under floating forests (of coal forest plants), as well as in
K> nearshore mud and sandy bottom habitats. Representatives of most major
K> groups of mollusks were overcome by sediments at the onset of the flood (in
K> Devonian, Silurain, Ordovician, and even Cambrian layers), but the numbers
K> caught in sediments increased as the flood progressed. Because of their
K> more diverse habitats, the mollusks were much less affected by the
K> permo-triassic transition than the brachiopods. Different species (for
K> example of nautiloids and ammonites) had different physiological tolerances
K> to the changing salinities, turbidities, temperatures, etc., and tended to
K> die and be incorporated into the sediments in a predictable order
K> worldwide. Many more mollusks, especially Prosobranchids, came into the
K> sediments as land areas were eroded. The worldwide distribution of many
K> molluskan genera, despite their present separation by continental land
K> masses, is a result of dispersal during the flood.
While you may snow people without any knowledge of paleontology with this
explanation, I find it ludicrous. There are several major problems with your
claims:
- The idea that currents during the flood preferentially pushed one group
of organisms one direction and another group of organisms another
direction, so well as to actually sort them by species, boggles the mind!
I challenge you to throw similarly-sized shells from a dozen different
species of bivalves and brachiopods into a big tank of sediment-laden water
and reproduce this amazing phenomenon.
- Your whole explanation is ad hoc and explains nothing. Why are all of
the hundreds of different types of ammonites extinct? Maybe they couldn't
take the salinity change of the flood. Why did the chambered nautilus
survive? Maybe it could take the salinity change of the flood. Such an
"explanation" explains everything and gives us no useful information.
Maybe the organisms DID have different physiological tolerances to changing
salinities, temperatures, or turbidities. Where's the research? Here's
another problem with this explanation. We know today, for example, that many
freshwater organisms (invertebrates and vertebrates like fish) can't tolerate
any salinity. Any many marine organisms can't tolerate changes in salinity
(Ever try to keep tropical fish? Any changes in temperature or salinity kill
them). Yet all modern organisms are modern (think about that!). None of the
present-day species of ANYTHING are found in Paleozoic or Mesozoic "flood"
sediments (yes, molluscs are found but not the same kind living in today's
oceans!). In a global flood, the salinities, temperatures, turbidity, etc.
would all be changing wildly. Why were no modern species preserved?
- Your model requires that single species will all survive the flood to a
certain point (with not one of them becoming fossilized) and then they will
all (to the last shell!) suddenly be overcome with sediment and die off.
Every shell around the world all at once. How else to explain that for
most individual species of invertebrate marine organisms (the most common
fossil), they are only found in a single geologic period (which, according
to your model, formed in a couple of days). You find a Mucrospirifer and,
you know you're in Devonian rocks. Remember that the geologic time scale
was worked out by correlation long before radiometric dating and mostly before
the publication of Darwin's "Origin of Species."
- Your model requires a perfect sorting mechanism by a chaotic event. The
young-earth creationist Ken Ham, a lecturer for the Answers in Genesis
organization (http://www.answersingenesis.org/), travels around the country
giving lectures where he claims (paraphrasing) "What would you expect to find
if there was a global flood? Millions of dead things buried in mud!" Then
he explains that's what you do see. Well of course he neglects to mention
that what geologists and paleontologists would expect would be millions of
dead things ALL MIXED UP because there's no plausible sorting mechanism for
organisms carried about in raging floodwaters! Even if organisms did end
up being sorted by size and environment, why don't we then find large
herbiverous dinosaurs, large Tertiary grazing mammals (also extinct), and
large modern grazing mammals all in the same flood sediments? They're all
about the same size and all live in similar environments. Similarly for
thousands upon thousands of like examples. The paleontological record
clearly shows that different populations of organisms inhabited the same
environment at different points in time -- the principle of faunal succession
first described by the English surveyor William Smith a full half century
before Darwin wrote "Origin of Species."
K> You offered another flood model:
S> That brachiopods were buried more quickly (even though many lived on stalks
S> above the sediment) while similarly shaped bivalves somehow fled from the flood
S> sediments (even though many live IN the sediment) and didn't get buried until
S> the flood was almost done. I find this rather hard to believe Karen!
K> So do I. It considers hydrodynamics and motility, but misses ecological
K> factors and more. My model has its deficiencies, too (I am no invertebrate
K> paleontologist). You may reject it, of course! But we have a lot to learn
K> about the characteristics and capabilities of these organisms.
Yes, but you guys are doing it backwards. Do the basic research first (looking
at the characteristics and capabilities of these organisms) and then do your big
hand-waving theorizing about a global flood. Then maybe you'd have some data
besides Genesis 7-8 to back up your ideas.
I'm no invertebrate paleontology either and I wish one were on the list to
comment on this since I'm sure they could do a far better job than I in refuting
this with more specific examples.
- Steve.
-- Steven H. Schimmrich, Assistant Professor of Geology Department of Geology, Geography, and Environmental Studies Calvin College, 3201 Burton Street SE, Grand Rapids, Michigan 49546 sschimmr@calvin.edu (office), schimmri@earthlink.net (home) 616-957-7053 (voice mail), 616-957-6501 (fax) http://home.earthlink.net/~schimmrich/