[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Dinosaurs to birds



At 10:54 PM 1/21/99 -0500, John Bois wrote:
>Then how do you explain the disappearance of enantiornithines?  More bad
>luck? 
>
That is certainly possible.  The exact factors that differentiate survival
and non-survival in a mass extinction are not known, and are probably
complex.  It is very likely that many traits that are adaptive in ordinary
times have little significance during mass extinctions, and it is possible
that accidental traits, that are selectively neutral most of the time,
become critical to survival.  I would call that luck.

In addition, many sorts of stress have an unpredictable aspect to them.
Even in areas otherwise stripped of life by the Mt. St. Helen's explosion,
there were small, protected sites where a few plants (and presumably
animals) survived.  Presence in such spots is certainly largely a matter of
accident.

--------------
May the peace of God be with you.         sarima@ix.netcom.com