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theP-T boundary



        Been distracted a bit lately so I didn't get back to the Permian
Park thread quick enough to keep it from fizzling. Hope nobody minds if 
I try to revive it.
        
        I did end up buying that Czerkas book "Dinosaurs, A Global View",
the last one left in Barnes & Noble. I was a bit embarrassed to find the 
magnificent Permian scene with the cynogs and Kannemeyeria was actually
Triassic, separated by the biggest chasm of all, the P-T boundary.

        This set me to thinking about how I made that error. The K-T is 
only the second greatest mass extinction in earth's history, dwarfed by
the Permo-Triassic (P-T). And yet on land at least, the scenery didn't seem 
to change that much. At the end of the K, the dinosaurs and pterosaurs were
gone from the land, the marine reptiles (except sea turtles) were gone, 
and the largest surviving (land) vertebrate was the size of a cat. Mammals
eventually filled all the large animal niches left by the dinosaurs. Cycads
and conifers, once major players, took a back seat to angiosperms. 60% of all
species went extinct is the usual estimate. A time traveling Dorothy would
take one look around and say "Toto, we're not in the Cretaceous any more!"

        On the other hand, most estimates I've seen say about 95% of all
species checked out at the end of the Permian. But the synapsids made it
thru. In fact the land vertebrates of the lower Triassic don't look all
that different from the Permian, do they? Granted no one group dominated the
Permian the way dinos did the Mesozoic, but did any major land vertebrates
cash in their chips at the P-T? How about fish? Higher plants? Was the scenery
very different but just not as well known, or well publicized, given that
neither the P or T is as charismatic as the Jurrasic?

        To my untutored eye, it looks as if the K-T extinction mainly
clobbered vertebrates, while the P-T hit hardest the more species rich
but less charismatic (to humans) inverts, especially the marine ones.
Is this the case?

        All of this raises lots of questions about what was different about
the two events. The causes? No one has suggested ameteor strike at the P-T. 
The two theories I am familiar with are massive volcanism and the oceans-turned-
to-soda-pop theory (CO2 bubbling up from the ocean floor) This last would
explain a greater effect on marine life. 

        Maybe someone can fill me in on known facts as well as the latest 
theories. 

                                TIA
                                   - Ron Dass