Date: Mon, 20 May 2002 01:03:20 -0500
From: Jeff Wilson 
Subject: RE: (urth) Liev's Postpostulate

>      From: 
>           "Dan'l Danehy-Oakes" 

> Jeff Wilson claims that
> 
> > Dollo's law is crap; it's violated by marine mammals, and 
> > moths that alight on trees in once-polluted areas.
> 
> ...well, no; it isn't. 
> 
> In the case of peppered moths, no lost organs are reappearing; 
> the a:A balance of certain alleles is shifting due to natural
> (or, I suppose, semi-artificial) selection. The "dark" genes
> had always been present as a minority in the "gene pool," became 
> a far more prominent proportion of the gene pool when industrial 
> pollution caused the trees they sit on to become darker in color, 
> and once again became less common as pollution control allowed
> the trees to regain their former light color. The basic papers
> on this, by Kettlewell's and Haldane, are both easily available
> in the Oxford reader on "Evolution," edited by Mark Ridley.
> 
> In the case of marine mammals, what has happened is that the
> lost organs have exactly failed to reappear -- all marine 
> mammals still must come to the surface to breathe; no gills 
> have reappeared. And, while the modified fins we call legs have
> re-modified themselves to a more fin-like structure, this isn't
> a case of anything lost reappearing. The only thing that might 
> be considered as a reappearance is the dorsal fin on some marine
> mammals; I don't know enough about how those evolved to give a
> legitimate answer to this.

In that case, I sit corrected but I don't see the relevance; the
function returns even if the anatomical detail doesn't. The Frenchmen
don't give the suspected abos a medical exam, they test their limbs'
function. Human hand or polymorphed pseudopod, if it can make nets it
ought to be able to work a shovel.

-- 
Jeff Wilson
How Am I Posting? 1-800-555-6789
"If your SecOp can see you, so can the enemy." -Cpt Law


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