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Re: "Random selection": an oxymoron.




On Sun, 24 Jan 1999 Dinogeorge@aol.com wrote:

> In a message dated 1/24/99 3:13:07 PM EST, jbois@umd5.umd.edu writes:
> 
> << Of the roughly 10,000 bird species, most 
>  are small and are staying that way.  Why? Because, as Collias says, being
>  small and flying allows them to conceal their nests.  This is a valuable
>  rule.>>
> 
> This "rule" can apply only to certain small birds. It has no applicability
> outside this narrow set of organisms. It is like calling the statement
> "nearsighted people wear glasses to see better" a "rule." Besides, tomorrow
> someone else will come up with a different reason that some bird species
> remain small. Then what will happen to this so-called "rule"?

But I am not saying that the development of such rules is simple.  They
are highly contingent on the species, environment, and everything else.  

> What you are calling "rules" are not rules, if there is a different "rule" for
> practically every different species. There is no generalization, if every
> "rule" is specific. We try to look for general rules, but the "rules" that you
> are displaying are limited in their applicability practically to the species
> for which they are created. They are not rules but characteristics of species,
> like "blue feathers" or "jugal expanded." There is no point to creating a
> welter of thousands of different rules whose applicability is so limited. You
> are just adding to the chaos.

But a rule like "birds stay small due to predation pressure" applies to a
great many species.  Ecological patterns are complex but not random.
And the
understanding of underlying patterns is not merely a subject for parlor
chat.  If the rules we perceive are accurate and have predictive power
they can be applied to conservation.  For example, edge predators are
better agents of extinction if their prey's range is chopped up into small
units.  Or, large plots of land harbor a greater number of species than
small.  And it seems to me that these rules involve complex processes;
they are not just species' characteristics.  E.O. Wilson is a great
reductionist, but I believe he would recognize the complexity of
ecological rules _and_ the importance of discovering them! 

> Cope's "rule" doesn't say "species grow bigger." It only notes a tendency.
> There are lots of reasons that species can grow bigger, there are lots of
> reasons species can stay the same size, there as lots of reasons species can
> grow smaller. None of these reasons amounts to a rule. There are no such rules
> in evolution; everything is contingent.

It doesn't matter if rules are contingent.  As long as they describe
empirical regularities they are rules.