Re: NANFA-L-- Re: the aquarium hobby as conservator of

Steffen Hellner (steffen-in-hellner.biz)
Fri, 12 May 2006 19:54:31 +0200

To me genetics is overestimated. Look-in-Cyprinodon diabolis. Extremely
small population, isolated for aeons, when released-in-Hoover Dam it
suddenly developed the ancient body shape and size back. If that inzest
doesn4t eliminate the ancient form over thousands of years, what can captive
rearing for some generations mean? Not much from my point of understanding.
If there is no competition then genes are extremely lazy in regard of
changing.

Am 12.05.2006 19:33 Uhr schrieb "Jerry Baker" unter <nanfa-in-bakerweb.biz>:

> Moontanman-in-aol.com wrote:
>> I have to disagree, release a large number of domestic goldfish into the
>> wild, in a pond or even a stream. In a very few generations you will have
>> wild
>> type goldfish again. I've seen it happen in even small ponds. animals are
>> often
>> genetically more plastic than we give them credit for.
>
> Indeed. The whole argument that captivity induces genetic drift, and
> therefor bad, is a tautology. Of course there is genetic drift because
> that's what happens when one population of a species is separated from
> another. It might not have anything to do with captivity and just be the
> process of natural evolution continuing along slightly different courses
> in isolated populations. Sure, the conditions of captivity can influence
> the evolutionary path, but that shouldn't matter much as long as the
> animals remain able to survive in their natural environment. Without
> constantly providing for genetic exchange between two populations held
> in isolation, of course they're going to drift. Keep them separated long
> enough and they may evolve into separate species. That's the way it works.
>
> It seems to me that trying to keep a population of some threatened or
> endangered creature genetically stable is as foolish as was the old way
> that the National Park Service used to try and prevent any changes in
> the forests. After a while the exclusion of fire and other disturbances
> was destroying the very forests they thought they were protecting. I
> don't think it would be helpful to actively prevent a species from
> experiencing the genetic drift that might allow it to adapt and survive.
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