[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
On Fri, 24 Mar 2000, Stanley Friesen wrote:
> At 03:11 PM 3/24/00 -0500, John Bois wrote:
> >Specifically, among terrestrial vertebrates the ONLY group that
> >experienced true extinctions were the dinosaurs!...
> Not strictly true, at least according to Archibald. His analysis of the
> Hell Creek and overlying layers shows the following: 50% extinction in
> Multituberculates, 89% extinction in Marsupials, 70% extinction in
> squamates, and 100% extinction in non-avian dinosaurs.
Yes, of course. However, these extinctions are also coincident with (but
definitley not yet attributable too) placental invasion at the time. So,
competition/predation hypotheses are very much alive for these particular