(urth) Mystery of Ascia/Agia

[Gerry Quinn]

From: "Jeff Wilson" <jwilson at io.com>
> On 1/21/2011 12:34 PM, Gerry Quinn wrote:

>> Unless variations are very small, the idea of a 'natural country type'
>> conflicts with Dollo's Law which was discussed here a while ago. Suppose
>> a race evolves in Country A according to the 'natural' pattern, moves to
>> Country B and after many generations adopts that country's natural type,
>> and then moves back to Country A again. If they go back to the original
>> type, they are violating Dollo's Law.
>
> Dollo's Law has since been weakened to allow reversion over millions of 
> years:
> http://www.pnas.org/content/91/25/12283.full.pdf
> "...we show that, in fact, there is a significant probability over 
> evolutionary time scales of 0.5-6 million years for successful 
> reactivation of silenced genes or 'lost' developmental programs."
>
> This is after the Book's time of authorship, so the Book doesn't have to 
> agree with it, but other RL observations included in the Book don't have 
> to agree with Dollo's Law as an absolute, either.

It would be foolish to take a law such as Dollo's as an absolute in any 
case - but it is a pretty solid general prediction if the conventional 
theory of evolution is valid.  (Of course, Wolfe has a reputation, justified 
or not I do not know, for Lamarckian tendencies.)

If there are substantial and various changes, they won't all be reversed.


>> What should happen according to Dollo's Law is that they will evolve
>> traits suited to life in Country A, but those traits will not be the
>> original traits. A country cannot have a single unique natural type.
>
> This doesn't prevent a continental area from have a convergent "look" that 
> newer populations can convince themselves ls essentially the same after 20 
> generations, even if it would really take more like 50.

I can't say much about what people might convince themselves of, but this 
'law' cannot reasonably be expected to apply in general.  For that matter, 
there are regions where considerably different looking peoples have 
cohabited for a long time.  Pygmies, for example, and their neighbouring 
tribes.

- Gerry Quinn