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From: ncramer@bbn.com (Nichael Cramer)
Newsgroups: sci.astro,sci.space,sci.space.shuttle
Subject: Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth)
Message-ID: <40171@bbn.COM>
Date: 19 May 89 03:18:20 GMT
References: <256@ringwood.Morgan.COM> <3200009@hpindda.HP.COM> <1212@irisa.UUCP> <13111@ut-emx.UUCP> <1216@irisa.UUCP>
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In article <1216@irisa.UUCP> saouter@irisa.UUCP (saouter yannick) writes:
>In article <13111@ut-emx.UUCP>, ethan@ut-emx.UUCP (Ethan Tecumseh Vishniac) writes:
>> It is also true that this is not the most dramatic mass extinction in the
>> fossil record. 
>
>Such collisions occurs about every 50 000 000 years and I've heard that others
>species have disappeared as suddenly as the dinosaurs did, so earlier
>collisions might be the cause for that, too.
>
>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.