Re: Fossil Records Show Biodiversity Comes and Goes

From: Carsten Troelsgaard (carsten.troelsgaard_at_mail.dk)
Date: 03/19/05 

Date: Sat, 19 Mar 2005 09:07:47 +0100

"John Harshman" <jharshman.diespamdie@pacbell.net> skrev i en meddelelse
news:IBE_d.20027$Pz7.8401@newssvr13.news.prodigy.com...
> George wrote:

snip

>>
>> My purpose in pointing it out was that it has been accepted for quite
>> some time,
>> so I don't understand your objection to it.
>>
> Well, "thought about" and "accepted" are two quite different things.
> Accepted on what basis? We just know it's true? It sounds nice? Or was
> this established on the basis of rigorous tests? If so, do you have
> citations? The Paleobiology paper you cited was one such test, which
> seems to show an effect in crinoids -- though again, greater speciation
> rates among the specialists compensated for the greater extinction
> rates. What else you got?

Whatever the specific details the two of you disagree upon, George has a
point in his example of the selection pressure a drowned reef could be. The
author of the below link estimates 1/4'th of the marine diversity to inhabit
the reefs. I figure that the Permo/Triassic event would count heavily in the
statistics of some cyclicity in diversity - the author does not find an
impact event very likely compared to the alternatives.

http://www.killerinourmidst.com/index.html#anchorContents

Carsten