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Extinctions Out of Sync?

In a message dated 95-07-29 04:12:15 EDT, you write:

>humans began to depart from the evolutionary checks and balances of the
>environment by manipulating the environment in responce to environmental
>challanges, we ceased to act "naturally" and the effects of our subsequent
>actions must be "unnatural". More over, "natural extinctions" are events
>that we have no control over. "Unnatural extinctions" (the ones we are
>inflicting on species today) would not occur were it not for our activities
>and could be prevented by appropriate action.
I respectfully disagree. The most recent mass extinction occurred ca. <10,000
years ago on the North American continent. The mammoths, mastadons, camels,
horses, saber tooths etc all died out. This time it was not a "rock from the
sky" but ancient man!  Are you arguing that these people were "out of balance
with thei renvironment'?  I submit that they were as we now are under the
circumstances!  The ancient Americans armed with the "nukes" of their time
(stone tools) were able to survive during repeated Ice Ages and successfully
hunt many of the above animals, to the humans benefit, to extinction. Even
when the climate was more moderate this situation would have probably been
accelerated. Since that time, man of course has evolved to the technological
beasts that we are now. Consequently, with mans continued productivity, and
longevity, someone (or thing) is bound to loose out in the long term. It is
inevitable that plants and animals that may have been already under some
_other_ stress  or already headed for extinction by non-anthropogenic factors
to now succomb to the effects of human activity. Imagine 5+ Billion people
forced to hunt and gather again and I dare say the extinction ratio would be
exponential!  Any way, I am aware that some _but_not_all_ of the animals that
have recently gone extinct or are endangered are a dirrect result of mans
folly. We must draw the line and be more objective when we start legislating
"endangered species protection". Remember, I think it was Bakker who
estimated that the average life expectancy of a particular species was 2-3
My. If this figure is corroborated, then pleontologists have a base line with
which to work with and hopefully bring some moderation to the
environmentalist-extremists movement. We can then turn our attention to the
daamage that we truly have caused and have a unique opportunity to study the
minor backgound extinctions that are going to happen  regardless of our
presence on this planet.

>To try to bring this string back to the subject area of the group; We, as
>palaeontologists, have a unique and vital understanding of extinction.
>Should we be bringing this to bear on the current environmental debates? If
>so, how? If not, why?

As I stated above, paleontologists and even geologists have a unique
perspective because we study various aspects of earth  and natural history
history. To paraphrase the addage, "those who don't remember that past are
doomed to repeat it" , could be modified to the past history of life on earth
is a model for which our future could be built. We do now that ancient
greenhouses were fertile grounds for origination and evolution so why the
doomsday scenario now? Volcanoes were even more active in the past and spewed
even more sulfides (acid rain) and chlorine (for CFC production and alleged
ozone depletion) and continue to do so today. The dubious "scientific" data
that the extremists use to scare the public and governments should be tossed
out and new, objective data collected. But objective eco-studies don't bring
in the research dollars does it?  Could it be that the phenomena we currently
observe are all natural, cyclic phenomena?  Finally, I agree, let's stop
dumping and polluting as much as possible, let's not hunt whales,  lets
reduce rain forest lumbering but let's do it form a sound scientific
framework that 5 billio+ humans can all live with!

                                                            Thomas R. Lipka

Paleontological/Geological Studies