As you said,
>This discussion is getting complicated! Karen Jensen's statements are "K"
>and
>my previous statements are "S":
>
>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.
Clearly, both mollusks and brachiopods were killed.
Brachiopods were more abundant in environments that were buried sooner than
the environments in which mollusks were more abundant at the time, but all
areas were affected.
Fewer mollusks became extinct because apparently they were more able to adapt.
>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).
Why there were few mollusks in the environments where braciopods dominated
is the question here. You may believe the evolutionary answer that they
hadn't evolved yet. I offer an alternative explanation that they existed
but most of them were not right where the brachiopods were. There are
fossil mollusks in Silurian, Ordovician and even Cambrian deposits that
look enough like modern forms to be immediately recognizable.
Those two observable facts show your model to simply be
>incorrect.
>
Depends what glasses one is wearing (evolutionary or intelligent design).
>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:
>
I don't doubt that there are problems. One of the reasons for this forum
is to test and modify our 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 need to word it better. Of course turbidity currents couldn't be
expected to sort particles by species! If brachiopods were there,
brachiopods could get tossed up in the currents. If few (or no) mollusks
were there, few (or none)
would get tossed about. I suppose one could make a case for more
brachiopods being carried up longer, because of their stalks, but I wasn't
thinking of that.
> 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.
Do you know of any place which has tanks set up for turbidite flow
experiments? I saw some done on a small scale (about a 2x6 ft tank, about
3 ft high). And Colorado State University has that great set of flumes for
sediment flow experiments. Is anyone doing turbidite studies?
>
> - 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.
Also, they may not have had planktonic larvae. The corals, echinoderms,
mollusks, etc with planktonic larvae could survive partly by many larvae
simply waiting (as they do during storms today) until conditions were such
that they could begin to grow well.
Why did the chambered nautilus
> survive? Maybe it could take the salinity change of the flood.
Well, it was the more common mollusks I meant there -- there are salt water
and fresh water forms of both snails and clams today.
Such an
> "explanation" explains everything and gives us no useful information.
Same with the evolutionary explanation of why there are so few Cambrian
mollusks: "they hadn't evolved yet". Both views are taking the observed
fossil record and offering ex post facto explanations.
> 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).
Yes. Tolerances today are very narrow in many species (what do they call
it -- stenohaline, etc.--) Others are still quite wide. Ones that were
narrow in the past, and many that were wide, became extinct. As things
specialize today they may become more narrow. Consider the fresh water
sharks in Central American lakes, clearly from marine ancestors.
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!).
Depends on how you define "kinds". Species are different, and genera, etc.
I'm thinking of plants and animals both. Many which look very much like
living forms are given different names simply to specify that they are
paleo. (And ones from different stratigraphic levels that look similar
otherwise are given different names because it would be "unevolutionary" to
have the same name over such a long stratigraphic span!) Today's biota is
different from the paleozoic fauna. That is expected in both models.
In a global flood, the salinities, temperatures, turbidity, etc.
> would all be changing wildly. Why were no modern species preserved?
>
The modern species are successfully adapted descendents of the (relatively
few) flood survivors. I wouldn't expect to see many of them as fossils, at
the species level. Most of the fossils are of the forms that went extinct.
The forms that survived have had to adapt to (radically different)
postflood environments, which means speciation, in some cases to the family
level --like the fish in some inland lakes, clearly from a common ancestor.
> - 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.
That is about what you would expect if a species was distributed such that
it was not inundated immediately, but when it was, the ecological
disruption was fatal to most all individuals in the population. Many of
the fossil beds are called "death assemblages" because it is recognized
that a great number died all at once. Similar order of organisms around
the world indicates similar order of habitats (seafloor, shelf, near shore,
etc.)
> 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."
>
There is reason to question the time aspect of it, but the orderliness is
impressive. It speaks of an orderly sequence of events. As I often say,
He doeth all things well, decently and in order, even the Flood.
> - Your model requires a perfect sorting mechanism by a chaotic event.
Interesting juxtaposition. But I am not so sure how chaotic it was.
Massive, vast, powerful, dynamic, extensive, intense, severe, unfathomed,
yes. But chaotic? maybe not.
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!
I think what he says is "Billion of dead things buried in rock layers
laid down by water all over the earth" (I saw a T shirt with that).
Some creationists (I don't know if this applies to him) unfortunately give
the impression that the flood was totally chaotic from the first moment of
the bursting of the fountains of the great deep through to the end. They
apparently have not carefully considered the complexity of the year-long
sequence of events in Genesis 7 and 8, and are unaware of the degree of
precision found in the stratigraphic record. I am sorry about this.
They need to know that the fossil record is not all mixed up. It does show
considerable order. The plausible sorting mechanism you embrace involves
widely spaced time periods. The one I hold involves ecological
distribution and much less widely spaced time periods during the stages of
the flood (and after). We have different opinions as to which is more
plausible.
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.
The fact that we don't indicates that they were not in the same
environments. In my model, the large Tertiary grazing mammals like
Titanotheres may have multiplied for a time in early postflood open
environments, soon becoming extinct (their brains were no match for those
of the mammals which became dominant as grasslands expanded). There were
no dinosaurs among them because the dinosaurs had already gone extinct.
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."
>
That is true, but the number of steps may not be as great as came to be
thought.
>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 wish I could do research on all the relevant topics for this subject! But
the history of life on the whole earth through all time is a big subject --
none of us can even know about all the research on all the topics, let
alone do all the research. We put the data we find into the framework we
have. Sorry it is incomplete.
> 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.
>
Yes. If we keep the discussions going maybe one will be encouraged to join us.
I appreciate your answers.
Karen