Re: Extinction

[Joseph Daniel <jdaniel@aristotle.net>]

Very true. The worldwde diversity of dinosaurs, particularly those found in cold
climates (those that would have been cold back then) and the length of time
dinosaurs were in existence does tend to argue against climate change being a
major factor in their demise as an entire group. It could certainly have played
a part and likely did, but unlikely as a starring role. I can see it causing
extinctions in certain parts of the world, but not in all without some other
influence at work.
Hey, maybe climate change killed off the northen ones and the meteorite wiped
out the tropical ones?:) (If anyone takes me seriously here, I will personally
hunt them down and annoy them).

Joe

"King, Norm R" wrote:

> I always have had a problem with climatic extinctions of major taxonomic
> groups.  Like dinosaurs.  I know they couldn't migrate very successfully,
> for reasons Joe Daniel brought up.
>
> Say it gets a lot colder, fast.  What about the dinosaurs (or whatever) that
> already live close to the equator?  I am always impressed by the daily high
> temperature readings in Freetown, San Salvador, Quito, Nairobi, etc. during
> the middle of the winter, when it might be zero degrees here in Indiana.  If
> our temperature regime were to suffer a further decline, I'll bet just about
> everything already living in equatorial zones would survive there.  However,
> the tropical climatological zone would surely shrink latitudinally.  But
> some dinos or whatever (e.g., banana trees, etc.) would hardly be affected,
> if at all.
>
> So, during climatic changes, some species or genera should survive.  Later
> on, those could repopulate areas (probably very slowly) that may indeed have
> been vacated due to the climatic downturn.  The fossil record would likely
> show a diversity decrease that slowly recovered.  But total extinction of
> every member of the group, everywhere?  I wonder.