Re: Hybrid Fish - A few cents more

[Billinet at aol_com]

Scott Hieber said, in part:

<< . . .If they are infertile/impotent, the traits wouldn't diappear into the
gene pool; the creatures would die off.  Of course, it's conceiveable
that the supply of sterile creattures in the wild could continuously be
replenshed by human machinations. . . . >>

I agree.  If the hybrids can't reproduce then they can't do any harm to the 
environment.  Restockings of sterile hybrids wouldn't have a significant 
impact,
I wouldn't think.  

Note that hybrids are not considered to be a species.  A species has 
developed 
thousands of years or more through natural selection, so that it's 
characteristics 
are those which lead to survival.  Fertile hybrids, on the other hand, have 
typically 
existed for no more than a few months or years and their genetic 
characteristics 
have been determined mainly by their breeders.  If these breed with wild fish 
the 
effect on the gene pool is unpredictable, but the resultant fish would be 
hybrids, not wild, and conceivably the wild fish would disappear, replace by 
something new.

And if I may add one other point to this already too long post:  Evolution 
doesn't happen through hybridization.  Darwin observed that it occurs when 
inheritable variations within a species give a competitive edge to those 
individuals who have it,  meaning that more of their offspring survive to 
breed, etc.

Bill