RE: paleonet PDF PAPER AVAILABLE

["Hope, Sylvia" <shope@xxxxxxxxxxxxxx>]

Please also send me a copy.  Thank you.
Sylvia Hope

> -----Original Message-----
> From: paleonet-owner@nhm.ac.uk [mailto:paleonet-owner@nhm.ac.uk] On
> Behalf Of schilar@tin.it
> Sent: Thursday, September 21, 2006 9:54 AM
> To: paleonet@nhm.ac.uk
> Subject: R: paleonet PDF PAPER AVAILABLE
> 
> 
> Can you send a copy to me?
> Salvatore
> ----Messaggio originale----
> Da:
> Jean.Guex@unil.ch
> Data: 21-set-2006 10.37 AM
> A: <paleonet@nhm.ac.uk>
> Ogg: paleonet PDF PAPER AVAILABLE
> 
> To anyone interested I can send the
> following paper in PDF form:
> 
> "Reinitialization of evolutionary clocks
> during sublethal
> environmental stress in some invertebrates."
> 
> Abstract
> This paper describes the influence of high environmental
> stress on
> evolutionary trends in some selected Mesozoic ammonite
> lineages and
> some protists. During extinction periods, many ammonoids
> are affected
> by drastic simplifications of their shell geometry,
> ornamentation and
> suture line. We observe that relatively tightly
> coiled ammonites can
> give rise to highly evolute forms or uncoiled
> heteromorphs with
> simple ornamentation and almost ceratitic suture
> line - a phenomenon
> called "proteromorphosis". Such simplifications
> often correspond to a
> reappearance of ancestral geometries (primitive
> ornamentation,
> evolute coiling or uncoiling) which suggest that the
> evolutionary
> clock of these organisms can be reinitialized by extreme,
> sublethal,
> environmental stress such as giant volcanism (including
> its
> consequences on diverse pollutions and on climatic changes) and
> major
> regressive events.
> 
> 
> 
> 
> 
>