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Re: pineal gland notes



In response to Flying Goat's latest:

>    Why did birds survive and not therapods?...

1) Birds are several orders of magnitude smaller than theropods were,  
and this makes a HUGE difference ecologically; 2) Recent birds are  
several orders of magnitude more diverse than theropods ever were  
(there are about 9,000 named species of birds), and probably were  
similarly diverse in the the latest Cretaceous; 3) birds are found  
virtually everywhere on the planet, including all sorts of Pacific  
islands inaccessible to terrestrial animals, which means that there  
are/were plenty of refugia available to them. Put these things  
together, and I think you will agree that birds vs. theropods isn't  
really a meaningful comparison - it's like comparing bicycles and  
Sherman tanks. Furthermore, all three of these factors would make it  
much, much easier for birds to survive a mass extinction.

>  I won't take
>"Well, dinosaurs couldn"t survive the nuclear winter" explanation  
because I
>don't think there was one...

There was a profound and long-lasting climate change at the K-T.  
There is plenty of evidence to back this up (forams, plant  
megafossils), and clearly something very profound happened to global  
climate patterns at the boundary, whatever caused it. However, I  
agree that cold intolerance per se may not have been the major reason  
for terrestrial dinosaur extinctions - as Stan Friesen just said in a  
post today, large body size (not to mention low standing diversity;  
mega-dinosaurs were always a minor, minor group in terms of taxonomic  
diversity) is all the "explanation" we need.

>     The only other way I can think of to measure what season it is  
has to do
with being able to measure magnetic polarities...

Like I said a couple posts ago, if you look long enough for  
"important" differences between any groups you will always find one.  
Be very careful here; you are using the same kind of reasoning that  
some people, for example, might use to argue for "innate" differences  
among human ethnic groups. You don't believe THOSE arguments, do you?