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From: oconnordm@CRD.GE.COM (Dennis M. O'Connor)
Newsgroups: sci.environment,sci.bio
Subject: Re: Condors & Otters & Cows, Oh My ! (Re: Bringing Back Extinct Species)
Message-ID: <6593@crdgw1.crd.ge.com>
Date: 6 Apr 90 14:41:37 GMT
References: <8696@pt.cs.cmu.edu> <6451@crdgw1.crd.ge.com> <151@garth.UUCP>
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Reply-To: oconnordm@CRD.GE.COM (Dennis M. O'Connor)
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Organization: GE Corporate R&D Center
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In-reply-to: phipps@garth.UUCP (Clay Phipps)

phipps@garth (Clay Phipps) writes:
] In article <...> oconnordm@CRD.GE.COM (Dennis M. O'Connor) wrote:
] >In [an earlier article], vac@sam (Vincent Cate) wrote:
] > ] ...
] >[...] mammoth cloning [...] can't bring back the species 
] >unless clones from many different ex-mammoths could be made.  
] >Even a dozen individuals wouldbe too few.
] >The same applies to endangered species. 
] >Once the gene pool is reduced to a few dozen individuals (living or dead), 
]                                   ^^^^^^^^^^^
] >it becomes nearly impossible to really resurrect the species.
] 
] Then I suppose that you have already given up on the California condor
] (Gymnogyps californianus).
] 
] As of March 23, there were only 33 California condors known still alive,
] and 2 fertile eggs known--on this entire planet, all in captivity. ...
] 
] The Andean condor, whose appearance is similar to the California condor,
] is neither the same species nor even in the same genus. 

Your rigth, I have given up hope for the California condor.  I appreciate
and support the heroic efforts of those trying to ressurect the species,
but in a thousand years ( a blink of the eye ) I doubt there will be
even one member of the species left.

This is why I feel we have to be more vigilant in protecting the genetic
diversity that remains in our ecosystem.

] >Cheetahs provide an example of this from nature. 
] >Theory has it that [the world-wide(?) cheetah population was] 
] >reduced to 200 or so individuals about 10,000 years ago. 
] >As a result, cheetahs will always teeter on the brink of extinction : 
] [...]
] >they are so close to genetically identical, 
] >they lack the diversity to survive sudden ecological change.
] 
] My understanding is that loss of viable habitat (especially important 
] because of the consequent reduction in carrying capacity) is a far greater 
] threat than anything else to the survival of most animal populations
] (is there significant disagreement on this ?).  There are notable exceptions:
] the fundamentally nonrenewable poaching of African elephants for their ivory.
] 
] I'm not convinced that the cheetahs are *practically* any worse off 
] than a lot of other animals retaining much greater genetic diversity.
] Cheetahs could certainly be hit hard by a sudden or cyclic disease, but 
] I *suspect* that encroachment by Homo sapiens is their biggest problem now.
] Can someone elaborate on the world-wide plight of cheetahs ?

I agree with you on the short-term threat. But take the long-term 
perspective : change is inevitable, and without diversity in a population
a single adverse change can destroy the entire population. Now there
is some recovery of diversity from mutation, but you won't recover
the original diversity that made the species what it was ; instead, if you
are lucky, you evolve a new species.

Look at the agri-corporation mono-cultures that blight our farmland :
( okay, I'm waxing poetic, I'm sorry )  In the past, single diseases
hafve destroyed entire counties worth of crops.  This was because
every genetically-identical plant in those counties had essentially
the same resistance to any particular disease : once a lethal disease
appeared, it propogated like wildfire.

The same could happen to cheetahs or California condors. The same DID
happen to the Clydesdale population of the US in the 1960's -- new blood
from Europe, imported by Annheiser-Busch, renewed and expanded the
gene pool and population level of the breed. Eventually, it is probable
that cheetah and condor will also fall victem to such an epidemic.
And it is sad.

Extinction is forever. So is the los of characteristcs (i.e. narrowing)
of the gene pool of a species.  Even if I'm wrong, isn't it better
too assume I'm right until we know better ?
--
  Dennis O'Connor      OCONNORDM@CRD.GE.COM      UUNET!CRD.GE.COM!OCONNOR
  "Let's take a little off the top ... a bit off the sides ...
    trim the back a bit ... Surprise ! You've been bald-ed !"