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Well, some of you that responded to my email about
change causing speciation have seemed to imply that in the past change has been
gradual, much more gradual than our current 'global warming' that we
are debating if it really exists. I am sure that if plants had
feelings, they would be very happy to see gradual changes. However, after
doing a little researching when this general topic of species loss came up, I
came across a book by W. S. Broecker, "Fossil Fuel CO2 and the Angry Climate
Beast". In it he describes the Younger-Dryas event and its believed
cause. This was without doubt an abrupt change in temperature, and was
world wide. I found a site for the book in pdf format and downloaded
it, most of which I read. Can't find the site again, but found another
interesting read, a lecture by Richard Alley, "Abrupt Climate Changes: Oceans,
Ice, and Us" that describes on page two the temp change and the time frame of
the start of the Younger-Dryer event, 10C drop in a decade, and maybe as
short as a year, and lasted about a 1000 years.
This was about 13/12,000 years ago, and look at the
enormous diversity we have now.
Cynthia, Prescott, AZ
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