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From: cramer@optilink.UUCP (Clayton Cramer)
Newsgroups: sci.astro,sci.space,sci.space.shuttle
Subject: Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth)
Message-ID: <1519@optilink.UUCP>
Date: 21 May 89 18:42:57 GMT
References: <256@ringwood.Morgan.COM> <3200009@hpindda.HP.COM> <1212@irisa.UUCP> <40227@bbn.COM>
Organization: Optilink Corporation, Petaluma, CA
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In article <40227@bbn.COM>, ncramer@bbn.com (Nichael Cramer) writes:
> In article <1493@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes:
> >In article <40171@bbn.COM>, ncramer@bbn.com (Nichael Cramer) writes:
# ## #Does anyone knows others example of strange disappearance ?
# ## 
# ## I don't remember the numbers (in species/yr) offhand, but I've read
# ## arguements (e.g. by S J Gould) that claim that we are *now* in the midst of
# ## the one of greatest (if not in fact _the_ greatest) of mass extinctions of
# ## all time.
# ## 
# ## If I recall right, the numbers work out to ~1 species/100,000 increase in
# ## human population.
# #
# #I've read that the current rate of extinction is about 15 species/century --
# #which is clearly far lower than ~1 species/100,000 increase in human
# #population.
# 
# CLAYTON
# 
# I checked my source for the above after I got home last night, and he was
# claiming a loss of 10,000 species/yr but he didn't cite any sources.  This
# does sound very high.  But on the other hand, it seems equally difficult to
# believe we've only lost 13-14 species in all of the 20th century.  (I've
# also seen figures in the 1-10/yr range.)
# 
# Do you (or anyone else) have specific references for what the actual value
# of this rate is?
# 
# Thanks
# NICHAEL

Nope.  I sure would like to see some numbers.  Now that I think about
it, I think what I had read (in a newspaper, so probably false) was
that over the time man has been on the planet, there has been an
average loss of 15 species/century -- not the same as the rate for
this century.

-- 
Clayton E. Cramer                   {pyramid,pixar,tekbspa}!optilink!cramer
Assault rifle possession is a victimless crime.
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