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Re: [GSP1954@aol.com: MORE DINOSAUR ENERGETICS] (fwd)



        To anyone interested in my two cents please look this over. I am a 
neuro-physiology graduate student and I don't care if dinosaurs were endo or 
ectothermic. However I do not see a problem with the methods or sample 
size that Ruben Geist and Jones used in thier paper.  

Greg Paul wrote:

>Jones says that people should refer to the "available information and decide
>for themselves". Good idea. For instance, CAREFULLY examine the data behind
>all the grand conclusions in Ruben et al's Science paper that Jones
>participated in. Note how many birds are used to help come to the conclusion
>that there is a fourfold difference between the cross-sectional area of nasal
>passages of endotherms and reptiles. Four, FOUR! That's just three big
>ratites and one heron. Hardly cutting edge science, indeed it is a grossly
>inadequate sample. (This is an example of how the Oregon people prematurely
>derive broad conclusions from insufficient data.*) I have measured nasal
>passage cross-section in over two dozen birds, plus an interesting giant
>mammal. Sorry Jones, your four fold gap does not exist.  As for dinosaurs
>having small nasal passages, have you bothered to look up the nose of a large
>horned dinosaur? You could park a 58 Buick in one of those spaces. Why did
>that not end up on your plot, which included only three, THREE, dinosaurs? I
>thought that in science the careful accumulation of large and therefore
>significant data sets were the hall mark of good science*. As for the
>supposed causal link between RT and metabolism, even K. Nagy - one of the
>preeminent field biologists - questions their importance (1995 Science
>270:736). 

        Hello, my name is J.Melville and I am a neuro-physiologist here at
OSU.  I just wanted to state for the record that although the data set
presented by Ruben Jones and Geist may be some what small and may possibly
under represent the diversity of endo and ectothermic animals, one fact
remains. There is a four fould difference in crossectional area of the nasal
cavities of these animals. This is based on very sound statistical methods of
multiple linear regression. The model that was calculated for the two lines
that they recieved described over 95% of the variance in thier data set and
the difference between the two lines was highly significant. This four fould
difference does exist in this data set!!!  So it is quite posiible that
through other anecdotal evidence that others may disagree with thier
conclusions but THIS DIFFERENCE IS REAL whether you choose to believe it or
not.

        There are however some problems with there data. 1) wieghts of
dinosaurs and the wieghts of some animals are estimated, 2) thier is only one
animal per point on the regression line. Also there sample is not that large.
All of these criticisms should have worked against thier data set!!! Not for
it. Lest this is unclear to anyone I will explain this briefly. Each point on
a regression ususallly represents the average of a population of
responses. So for example if you are trying to make a regression of oxygen
consumption as a function of time while running you could hook up an O2 meter
to someone and have them run for an hour and take readings at every 5
minutes. You could then plot your results and try to model the response using
linear parameters. However, with only one response at any given point in
time, you most likely would not get the best linear fit.Thus, you would want
several trials or several different people to run for an hour and take the
same measurements and then plot this data on top of the data you originally
got.

        The Ruben group estimated thier wieghts and only used measurements
from one animal per point. This should have worked against thier data not for
it!!! I hope have followed me to this conclusion. If you have any further
questions about this feel free to contact me. I personally find it rather
amazing that even with such a small sample that the Ruben lab got such good
results. We are talking excellent adjusted R-squared values.  With this data
in mind (not looking at dinosaurs) I would have to conclude taht nasal
turbinates and effectively nasal crossectional area is an excellent character
for determining the metabolic state of an animal.  I originally like most of
you did not think that this research was going to be significant and I am not
interested in dinosaur physiology at all. However after I looked at and
critiqued thier statistical analysis and ran it by several statisticians here
on campus I could find no fault in thier data. I think that if you were to
look at thier research and seperate it from the three dinosaur points taht
are on this graph that you would be hard pressed to refute thier findings.
However even with data from three dinosaurs I do believe that the Ruben's lab
work sheds important light on the possibility that dinosaurs were
ectothermic. To anyone interested just pick up the last issue of Discover
magazine and read the article for yourself it makes sense. If anyone out
there thinks that there data is better or refutes thier data why not do some
multiple linear regression analysis on it, instead of refuting them with ad
homonym attacks on thier character. I will even do it for you. Please send me
the estimated wieghts of your dinosaurs and the nasal crossectional area. Of
course you must assure that during the process of extracting the matrix that
you have not destroyed anything. Please make sure that your methodology is
sound in essence. I would be happy to examine your data sets and compare them
to thiers.  Please contact me if you are interested.


Cheers and Happy Holidays. JM