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Re: Origins (was: Re: Sharovipteryx)



Regarding this debate...

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>> <Dinogeorge@aol.com> 05/25/00 02:06PM >>>
In a message dated 5/25/00 12:44:09 PM EST, rowe@psych.ucsb.edu writes:

<< The essence of science is not the telling of stories that make sense; it

is the testing of ideas with empirical observations.  If no observations
can 
recognizably be used to test an idea then the idea is not scientific.  And

the purpose of this list is to provide a forum for the discussion of
dinosaur 
*science*.  >>

Then you might as well close the list, because there is absolutely >no< 
empirical way to test >any< of the scenarios, hypotheses, theories, and so

forth that have been brought forth in dinosaur paleontology over the past
two 
centuries with respect to dinosaur behavior or evolution, period. >All<
these 
things are Just So Stories, some perhaps based on a bit more detailed 
analyses than others, but conjecture nonetheless, since we have no way to
go 
back in time to observe what actually occurred, measure internal
temperatures 
and observe feathers, track how dinosaurs evolved, and note how dinosaurs 
behaved. It's >all< conjecture, with only the most outrageous hypotheses 
(such as flying giant sauropods) excluded and only the most obvious 
conclusions (such as that dinosaurs laid eggs) fully substantiated. These 
debates will continue endlessly with no hope of resolution; it's not even 
possible to assign a >probability< of correctness to a hypothesis. The only

empirical things in this science are the actual specimens we find, from
which 
we can draw only the most elementary inferences. Face it: Nature is full of

counterexamples to every plausible scenario, and there's no reason to
expect that this was not as true during the Mesozoic as it is today.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Actually, Mickey's statements are quite correct. 

First of all - The mixing of the two hypotheses in questions, origins of
taxa versus origins of flight, is logically awful - they are totally
independent questions. This is the logic that seems to totally escape
Feduccia, for example, and why 90% of his statements in Florida were totally
useless for the debate he was in - on the origins of birds. Some were
interesting on the origins of flight, although I thought Shankar was better
at arguing related  points than Feduccia was on this matter. Make all the
arguments you want about bottom-up or top down, but you have said nothing
that affects the discussion of whether birds are from dinos, are only
distant cousins of dinos, or dinos are from birds. Nada. Nil. Nothing.
Period. Remember, I'm intuitively convinced that flight originated from at
least partially arboreal theropods rather than running ones. I only just
have intuition right now, however, on the arboreal part - the phylogenetic
work nails the theropod connection.

There are established and useful procedures for analyzing quantitatively
and repeatedly the relationships among the taxa we are interested in. All
are welcome to use them. All are welcome to be explicit about the criteria
they use for accepting or rejecting the results. All are welcome to develop
new algorithms, if they are clever enough, that get around any aspect of the
existing ones that they find scientifically problematic, such as strict
parsimony. No one is entirely happy with the behavior of the available
algorithms at this time, but they are better than arm waving by many orders
of magnitude. You want to suggest dinos are secondarily flightless birds, do
the work and show exactly what you have to do to the phylogeny - and what
the cost of doing it is - to allow this to happen. How many extra steps?
What is the total cost in length of ghost lineages? etc. Do the work, show
the results. Show the data and then make your case. That's what the people
who have been favoring dino origins have done. It's a convincing case and
the general audience of zoologists/paleontologists/and other evolutionary
biologists have seen it as such to an overwhelming degree. The data are
there and they can see why the conclusions are reached. You really think
birds were the start of the whole mess - do the work and present it. That's
exactly what the small group of anti-dino origin researchers have failed to
do. They won't even try to make their case in this way. That's why they have
totally failed to convince anyone except themselves. They haven't done their
job. Period. Wish they would - the world would be far more interesting. I'd
do it but I cannot, for example, give you Larry Martin's take on his
different coding of characters relative to Luis' or Paul's or Tom's, etc.
He's got some interesting ideas and may even be right. Well code the damn
characters and do the analyses. The problem is 95% of the community is
speaking one language and the others refuse to vocalize at all.

Now about functional hypotheses and hypothesis testing. Sorry George,
you're really wrong here. There are  many works that show how developing a
rigorous series of hypotheses and testing predictions made by them allow us
to do real science in historical areas such as paleontology. It's been a
wonderful area of discussion for years. Dan Fisher, for example, has done
some amazing work in this field and you certainly can do the same with
dinosaurs. Dan has 3 papers on fossil horseshoe crabs that are wonderful.
One makes you walk away knowing exactly how and how fast Mesolimulus could
swim. And if you want to argue, you can go right to his work and analyze it
step by step. Not a just so story.

Sankar's been working on developing similar models for top down and bottom
up models. A great step and  I'm looking forward to delving into his results
when he is done. Arboreality, will take some thought and lots of dicussion
and it will probably be much easier to make strong arguments against some
forms being arboreal than requiring others to be arboreal (and to what
degree?). But obviously any smallish/gracile archosaur has an advantage
towards being preadapted to being arboreal, and this could be a
bird/protobird or a theropod as protobird. There are many ways to be very
rigorous and test various hypotheses without degrading to just-so-stories.
Going back in time, although would be nice, is not necessary and if George
truly feels that historical sciences are all just-so-stories then I don't
understand  why he has the exceptional interest in them that he so obviously
does.

However, I'm not trying to pick on George. He obviously contributes lots to
lots of things and so let's decouple George from what I am arguing against
here because the just-so thing is a common misconception. We really need to
get people who work on dinosaurs to get as quantitative and rigorous as
possible - there are many schools without paleontologists because of the
incorrect assessment by other faculty that paleo is a soft science, depsite
the fact that today's paleontology is one of the most quantitative areas in
natural history. It isn't soft at all and you only have to read much of the
research to see this, or try to go through the review process with bad
analytical (or no analytical) work. Actually, if you read papers from other
sciences where they use quantitative methods - and I do because I'm into
quantification and different methods - it's amazing that in many areas they
get away with sloppy analyses that would be nailed in our major journals.
They get away with it because even their sloppy science has numbers attached
and this gives a facade of rigor for many studies. I like numbers but very
often they are used non-rigorously in these works. This includes many "hard
sciences", by the way.

Anyway, sorry about the length, but it is very important to push for
rigorous analyses at every step. They do not at all preclude any specific
hypothesis but certainly lead to ways to evaluate the hypotheses you have.
Just so stories are fun and make a nice impetus to start research in some
areas - they give you the ideas for developing hypotheses and ways to
analyze/test them. But they are only useful for a start, they are not useful
as the end product.

Has anyone really spent any time with this new specimen of Longisquama I
keep hearing about? I have heard conflicting notes that 1) the featheroid
things can't possibly be feathers, 2) they are really good feathers, and 3)
they are as good at being proto-feathers and dino fuzz is. Would be fun
either way, but inquiring minds want to know.


Ralph Chapman

Ralph E. Chapman
Applied Morphometrics Laboratory
National Museum of Natural history
ADP, EG-15  NHB, 10th & Constitution, NW
Smithsonian Institution
Washington, DC 20560-0136
(202) 786-2293, Fax: (202) 357-4122
Chapman.Ralph@nmnh.si.edu