Re: Pollen From Permian/Triassic Extinction Show UV Induced Mutations

[Richard W Travsky <rtravsky@uwyo.edu>]

On Sat, 18 Oct 2003, Nick Pharris wrote:
> Quoting Richard W Travsky <rtravsky@uwyo.edu>:
> 
> > 
> > http://dsc.discovery.com/news/afp/20031013/pollen.html
> 
> > The prehistoric mutations probably occurred after gas and dust from
> > massive volcanic eruptions damaged Earth's ozone layer, resulting in a
> > torrent of damaging ultra-violet radiation from the sun, according to
> > Clinton Foster, of Geoscience Australia, who presented the findings at a
> > recent conference at Utrecht, Netherlands.
> > 
> > "An extreme change in the environment resulted and that caused conifers to
> > produce mutant pollen," Foster told ABC Science Online. "The fascinating
> > thing is that modern conifers show just these sorts of mutations in
> > response to stress, such as extreme cold, dryness, or the Chernobyl
> > fallout." 
> 
> OK, so the mutations do not necessarily indicate the presence of DNA-damaging
> radiation, thus mooting Foster's whole argument about the ozone layer.  Or did
> I miss something?

Elsewhere in the article:

 "About 250 million years ago the world was an alien place, with what is
 now Russia and China separated by thousands of kilometers and an immense
 ocean," Foster said. "The only thing that linked the two land masses was
 the atmosphere.

 "Sudden and drastic changes in the atmosphere, such as those caused by
 massive volcanic eruptions, would have released huge amounts of dust and
 gases into the air. The ozone layer would have been damaged and there
 would have been a subsequent increase in ultra-violet B light." 

The same species of trees widely separated showing the same effects is
seen to rule out other forms of stress.