Michel Boucher wrote:
> Del Cecchi > wrote in
> :
>
>
>>And the blight that ravished Ireland, long before GM or whatever?
>>Or the pest that wrecked the grapevines in france?
>>
>>Or Dutch Elm Disease, or the disease that killed all the wild
>>American Chestnuts?
>
>
> One would have to look, but each was probably had some connection to
> loss of diversity. How is it that species survived in great varieties
> before these occurences? There must have been blights then too. The
> quality of genetic diversity is that some benefit while others suffer.
> If you only have one variety left, the entire species can disappear.
>

Nope. American chestnuts grew wild, as did many elms that were just
seed grown. Then a pathogen was introduced that they had no resistance
to and they all died. Even the elms in a mixed forest died.

See the current problem with beetles and lodgepole pine in colorado.

Over thousands of years either the species will happen to have some
resistance which will repopulate, or it will be wiped out. See what
happened to native diverse lake trout in lake superior when the sea
lamprey got in.

If you have the right kind of diversity, you won't miss one species.
The world goes on.

--
Del Cecchi
"This post is my own and doesn’t necessarily represent IBM’s positions,
strategies or opinions.”