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

["Jaime Headden" <ja_headden@qilong.8m.com>]

I wrote:

<<(Predation/competition extinction models) would seem to make sense in regards 
to an extinction event on a population, rather than
a global mass extinction of a percentage (however small) of a given range of 
species. Climate changes, or disease, or other natural
disasters or alterations can effect a wider range of species...>>

John Bois (jbois@umd5.umd.edu) wrote:

<I don't think this is an accepted assumption.  Certainly it would be true if 
species were isolated from each other.  Is this the
case?  If not, the evolution of new traits should be expected to have profound 
effects on species composition.>

  But this is about extinction factors. Isolated species should be free of 
non-catastrophic vectors of extinction, such as disease,
because if it can't get there, they cannot die. However, global factors need 
not be limited to one factor, as explained before, and
though it is indeed not an "accepted" assumption, it is a prodigious one that 
supports methods of possible extinction. After
replying to an argument that predation factors should affect global extinction, 
I responded that this is unlikely given the
selectivity of such factors, like disease. One requires much broader 
circumstances to explain what we see, even if remote regions
were affected in part (or in whole) by the other factors.

  Instead, I note that, aside from the timing of events, three extinctions 
should take place during the end-Permian era:
  1) the initial terrestrial/atmospheric warming killing less resilient species 
not capable of dealing with temperature changes and
increasing aridity, and ozone begins to decay;
  2) resultant marine/oceanic warming and die-off and release of gases that 
help erode atmosphere;
  3) a secondary terrestrial extinction as marine gases begin to add to the 
desolation on land and in the atmosphere.

  This would appear to explain how different regions can have different 
timings, and constraining down the terrestrial events does
not appear to effect the overall picture; rather, it may have operated for over 
several tens of thousands of years, an inversion of
an ice age. Disease and such will lead to limited deaths, and in-population or 
among limited populations, as is the effect of a
contagion. Any quality of mutation is non-selective initially and should not 
have an observable effect (here, just morphological)
for at least a million years or more, much less than time has been given to the 
Permotriassic faunal transition and Triassic faunal
recovery. Using human ancestors as a model, one can see that in just the 
thousands of years, changes along a lineage, as such that
may evidence mutation factors through environmental controls, the morphological 
changes noted are corollary to the species
identifications. However, if the mutation-inducing events were of UV as 
suggested, perhaps the greatest effect was on plants, not
animals, and this made them unfruitful as nutrition were concerned; loss of the 
food source then leads to a chain reaction, and this
is another global factor that may have worked after the secondary ozone decay 
noted in Phase 2 above.

  Cheers,

  Jaime A. Headden

  Little steps are often the hardest to take. We are too used to making leaps 
in the face of adversity, that a simple skip is so
hard to do.  We should all learn to walk soft, walk small, see the world around 
us rather than zoom by it.

  "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)