[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Dinogeorge Digest #15



Subj:   Re: _Night Comes to the Cretaceous_
Date:   98-08-08 22:29:04 EDT
From:   Dinogeorge
To:     jwoolf@erinet.com
CC:     jbois@umd5.umd.edu, MICHAELS@preit.com

In a message dated 98-08-08 17:49:51 EDT, jwoolf@erinet.com writes:

<< The Law of Parsimony says that the simplest explanation which covers
 _all_ the facts is preferable over more complicated explanations.  The
 impact scenario is not parsimonious as long as it fails to explain all
 the facts.  >>

The impact scenario is by far the most parsimonious explanation of the K-T
extinction. One impact, wipes out almost every significant life form. Those
that are left were lucky; there is no pattern to the survivors, except that
they tended to be small rather than large. These are all the facts that
require explaining.

Subj:   Re: _Night Comes to the Cretaceous_
Date:   98-08-08 22:24:57 EDT
From:   Dinogeorge
To:     jwoolf@erinet.com
CC:     jbois@umd5.umd.edu, MICHAELS@preit.com

In a message dated 98-08-08 17:49:51 EDT, jwoolf@erinet.com writes:

<< Illogical.  The extinction was selective: all nonavian dinosaurs, but no
 birds; mammals hurt but not wiped out; cold-water organisms less
 affected than tropical ones; marine reptiles more heavily hit than fish;
 etc.  A good shorthand way of describing the extinction on land is that
 pure ectotherms (amphibs and lower reptiles) and pure endotherms (birds
 and mammals) survived, and everything with a metabolism in between was
 wiped out.  The fact that the extinction was selective indicates there
 is a *reason* why some groups survived and others did not.  I want to
 know what that reason was.  The asteroid impact scenario doesn't say. 
 Therefore, I find the impact scenario an inadequate solution to the
 problem. >>

This is all completely irrelevant to the question of what killed the
dinosaurs, as I've pointed out already. Also, you're quite wrong that pure
ectotherms and pure endotherms survived, and "everything in between" was
wiped out. Most tetrapod species did >not< make it across the K-T boundary.
You could probably count on the fingers of one hand the number of tetrapod
species (herps, mammals, birds) that can be reliably identified on both sides
of the K-T boundary. For that matter, how about providing a list of these; it
should be really short?

Remember, for a species to survive, it is only necessary that a small
population of individuals somewhere remain alive through the crisis.
Ninety-nine percent of the population can be eradicated, and the remaining
one percent will refound the species. This is luck, plain and simple.

Subj:   Re: PRE-OLSHEVSKY BCF
Date:   98-08-08 22:01:54 EDT
From:   Dinogeorge
To:     m_troutman@hotmail.com

In a message dated 98-08-08 18:39:28 EDT, m_troutman@hotmail.com writes:

<< Also, before I go on, I must give a real positive endorsement of 
 _Origins of the Higher Groups of Tetrapods_.  Some of the best articles 
 in there are Witmer's and L. Martin's (excellent article on the anatomy 
 of _Archaeopteryx_ where he argues convincingly that the squamosal was 
 absent in the creature).  The whole book is good. >>

Yes, this is a truly excellent book: It's one of a few dozen books I didn't
leave behind in Buffalo when I moved back to San Diego in 1997. I refer to it
quite frequently.

Subj:   Re: PRE-OLSHEVSKY BCF
Date:   98-08-08 21:59:47 EDT
From:   Dinogeorge
To:     m_troutman@hotmail.com

In a message dated 98-08-08 18:39:28 EDT, m_troutman@hotmail.com writes:

<< So in response to somebody's claim that Olshevsky came up with the idea 
 of secondary flightless or arboreal theropods, let me say that it was 
 Abel who first developed the idea.  Anyway, George deserves credit for 
 coming up with the "complete picture". >>

Actually, I hadn't heard of Abel's papers until I read Witmer's; I arrived at
BCF quite independently of Abel, although about 70 years later. I was
absolutely delighted to discover that a "real" paleontologist had come up
with this concept all the way back in 1911, but was disappointed to learn
that he had, for some reason, given up on the idea by the late 1920s. I think
it may have had something to do with Heilmann's _Origin of Birds_, which
discredited the idea that birds descended from dinosaurs (largely because
theropods were not known to have had wishbones then) and placed their
ancestry among the non-dinosaurian thecodontians. Unfortunately, Heilmann was
wrong, but he sent paleontologists on a wild goose chase for the next 50
years, from which some even now have not yet recovered. The Abel papers are
quite difficult to obtain photocopies of; I still have only an excerpt from
the 1911 paper in my files. Perhaps the British Museum can provide copies?