Re: changing rad levels over time (2)

["Harald Weiß, D-24147 Kiel" <weiss@ki.comcity.de>]

Andrew Karam wrote:

> One thing I forgot to mention in my previous message is that we are
> trying
> to find out if the ability to withstand higher radiation levels in the
>
> distant past could have carried on to current organisms.

...

> If anyone can think of a plausible mechanism for mutation repair to
> retain
> primitive capabilities over this length of time OR if anyone can
> suggest
> some test to show that modern organisms have mutation repair
> capabilities
> similar to those of early organisms, we'd appreciate your input.

Hello Mr. Karam,

Many years ago (it must have been between 1978 and 81) I saw a review
about available data on effects of low level radiation. It was published
in Health Physics and the author came to the conclusion that the
statistic significance of any single study was weak, but in sum they
showed that slightly elevated dose rates were beneficial as they
produced less cancer than normal or even "zero" doses. I had the
impression that lower organized and older forms of life (algae, insects,
...) showed higher resistance than newer and highly developed forms like
mammals. This led me to the hypothesis that the optimum dose rate for an
organism (equilibrium between harmful and beneficial effects) is that,
under which it initially developed since this is the environment for
which this being was constructed by evolution. Will this fit your
calculations on rad levels in geologic time scales?

Greetings, Harald
--
Harald Weiss                 weiss@ki.comcity.de
Preetzer Strasse 263         Tel  +49 431 7859659
D-24147 Kiel                Fax  +49 431 7859658
..