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Re: Extinction (was Jurassic Intelligence)
> > > Well then, we should be sitting pretty - no animal I know if in the
> > > history of the Earth has had such a wide geographic distribution.
> > > Even most of our domestic animals fail to match our range: I think
> > > only the dog and *maybe* the cat are found *everywhere* humans are.
Karen E. Richardson responded:
: Sorry for the delay in commenting I've been away and had alot of mail
: to wade through. With regards to wide geographic distributions -
: what about BIRDS they are everywhere man is and more so, penguins in
: the South Pole etc and the Arctic Tern which traverses the whole globe
Everything seems relative when it comes to "success" in evolution. (however
one wants to define "success"). Even with wide geographic distribution, you
still need to invade many ecological niches. And you still should diversify
your clade with multiple taxa.
Using Homo sapiens as an example, we are not going to be as successful as
the Dinosauria, because we are only one species. That is not a good sign of
taxonomic health. According to Robert Carroll in his text book _Vertebrate
Paleontology and Evolution_, quoting others, Carroll lists the average
species longevity of Cenozoic mammals as 2 - 3 million years. For genera,
the average longevity is 8 million years (p. 574). Although I can't remember the
ref., someone has reported that Triceratops lasted only 5 million years.
It becomes obvious that it pays to have lots of different taxa in different
genera, families, and sub-families. The dinosaurs were successful because
they were taxonomically-DIVERSIFIED, *not* just because they were geographically
widespread. In fact, the dinosaurs were *so* diversified that they actually
survived the K/T extinction!!!
The dinosaurs living today are only highly diversified on lower taxonomic
levels. The Mesozoic dinosaurs were diversified at high taxonomic levels.
Summing this whole thing up, I can't imagine how a species like Homo sapiens
can ever dream of being as successful as the Dinosauria. No single species could
ever hang on for 225 million years. Well..... maybe if we start stockpiling
our Spam, Velveeta, canned chili, and Dr. Pepper, we might just be able to make
in another 10 million years......naaah....the cockroaches would just steal
it from us.....