[asa] How paleontology works

See below.

-- 
James Mahaffy (mahaffy@dordt.edu)          Phone: 712 722-6279
498 4th Ave NE
Biology Department                                     FAX :  712
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Dordt College, Sioux Center IA 51250-1697
>>> On 9/11/2006 at 8:18 AM, in message
<a89e52290609110618h6cef0eefx4d4eb65d9f8e3fad@mail.gmail.com>, "Rich
Blinne"
<rich.blinne@gmail.com> wrote:
> On 9/10/06, Bill Hamilton <williamehamiltonjr@yahoo.com> wrote:
>>
[snip]
> You mean you want an HR diagram? That's in all undergrad Astronomy
> texts. Actually the paleontologists do that one better than what you
> are asking. They predict using evolutionary theory where say a
> transitional form say a fish that can walk might exist. Here's how
> they knew  where to look for Tiktaalik according to Nature News:
> 
> "Daeschler and Shubin set off to find this missing link in the
> evolutionary chain back in 1999. The pair targeted Ellesmere Island
> after noticing that it was listed in an undergraduate textbook as
> exposed Devonian rock that had not previously been explored for
> vertebrate fossils.
> 
> The desolate area was reachable only by plane, and the weather was
so
> bad that field work could only be done for about two months each
> summer. The team first walked around the rocky outcrops looking for
> fossils of plant life that indicated stream or delta sediments, in
> order to target areas that had once hosted shallow waters. 'That is
> where the action is on the fish-to-tetrapod transition,' says
> Daeschler."
> 
> Sure enough they found the fossil there. This is how you make
> so-called historical sciences experimental. Similar techniques are
> used in astrophysics where colliding galaxies were recently used to
> determine whether dark matter exists.
This gives the wrong impression that most paleontology works by people
knowing there should be a transition fossil and then looking in the
appropriate age rock and finding it.  Mostly that is NOT how new
interesting fossils or "transitional" fossils are found. If it were we
would have found the transition fossils to the angiosperms (flowering
plants) and most invertebrate fossils.  We know where they appear in the
fossil record but most appear without obvious transitions and is not for
paleontologists looking for them.  Before Keith picks on me,I am not
denying transitional fossils.  Iit is easier to find transitions in the
vertebrate record than invertebrate record.  And I do know something
about fossil (graduate work in paleobotany) and teach paleontology at
Dordt. 
Let me share the other side of how paleontology sometimes works.  Back
in the late 70's I was working on paper on a fossil plant,
Microspermopteris.  It had been described as lacking leaves.  That was
wrong.  It just had long internodes and the leaves weren't seen by the
original describer of the genus.  In any case, my original article did
not draw any phylogenetic inferences to the status of this plants to
other pteridosperms.  I did see differences in the genus from different
parts of the US (our lab had the biggest collection of coalballs
(petrified coal-swamp peat) from the US.  However, I was told by the
person mentoring my first paper that I had to hypothesize what the
phylogenetic relationship.  Eventually, I had to confess I
philosophically did not believe that everything had to be
phylogenetically related.  And alas another lab meanwhile published on
the anatomy of the genus.  
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