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Re: Dinosaur extinction

Dear John

Thanks for your comments. I hadn't seen the paper you cite (Bromham, 
L., M. J. Phillips, and D. Penny.  1999.  Growing up with dinosaurs: 
molecular dates and the mammalian radiation.  Theoretical Review
of Evolutionary Ecology 14:113-118). I have seen another similar 
article in TREE. My question was prompted by David Penny's talk on 

David did not mention any palaeontological data whatsoever in relation 
to his dinosaur extinction hypothesis. What he did say was that he 
feels that in principle we should attempt to study past events by 
investigating processes that can be measured today. What he means by 
this is that we should consider the history of life in terms of 
phylogenies recontructed from gene sequences, rather than focus on 
"contingent" events such as bolide impacts which cannot be studied 
directly. Before everyone starts screaming I must make it clear that I 
find this claim highly illogical. David said that his views are much 
closer to Dawkins than Gould in terms of evolutionary mechanism. Thus 
David believes that in studying evolution we should focus on selection 
rather than contingent events in earth's history. David's views would 
seem to infer that in answering questions about animal evolution 
through time the results of molecular phylogenies on extant taxa have 
primacy over geological and palaeontological data. Let's be clear here: 
David is no crackpot - he is one of the world leaders in the study of 
molecular evolution. This is why I posed the question: is there any 
fossil evidence for size-related patterns in dinosaur extinction in the 
late Cretaceous?



Kendall Clements