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Re: Dino Fest report



>Three example patterns or trends that appear among living things
>through geologic time are:
>     1) the acceleration of biodiversity,
>     2) the increase of activity levels in living things, and
>     3) the increase of behavioral complexity.
>"The Place of Dinosaurs in the History of Life"
>By Dale Russell (National Museum of Natural Sciences, Ottawa)

  IMHO, our knowledge of dinosaurs is not complete enough to establish these
trends as valid. They may be true, but I don't think we have enough evidence.

>on average, Cretaceous dinosaurs were smaller compared to Jurassic dinosaurs.

  The largest sauropods known are from the Jurassic. But the largest theropods
(tyrannosaurs) are from the Cretaceous. I would have to see Russell's evidence
to accept his statement.

>Dinosaurs did evolve: later dinosaurs could out-compete earlier dinosaurs.

  I wonder! If we created a Jurassic Park, and a Cretaceous Park, and took down
the wall between them, what would happen? I am not convinced that all Cretaceous
species are superior, but perhaps only better adapted to the climatic changes of
the Cretaceous period.

>Because of the continuing complexities of modern life,
>dinosaurs (with their deficiencies in activity levels) could not
>be competitive with modern mammals, particularly on a mainland.
>We see there is a change in biological fitness in animals
>through time.

  Oh no! Mammalian bias again! This sounds like the very old idea that life
has been evolving toward a pinnacle of achievement (man, of course). The main
factor in the evolution of life on Earth has been the mass extinctions, which
"resets" the playing field from time to time. What if tomorrow we were to dig up
Russell's intelligent "dinosauroid" fossil from a Cretaceous deposit? It has
been estimated that we know only a very few percent of dinosaur species. We do
not know enough about their activity levels to make a comparison, unless, again,
we adopt the old idea of dinosaurs being stupid, sluggish, cold-blooded animals.

Scott Horton
Geophysicist/Computer Programmer