Re: Punk eq vs gradualism

[Jeffrey Martz <martz@holly.ColoState.EDU>]

>    ie What was Darwin's theory of evolution (wasn't it natural selection /
> adaptation rather than an actual theory of evolution?)
>    and I thought I read that the gradualist model was not proposed by Darwin

     By the time Darwin came around, evolution was not a new idea.  
Darwin's big innovation was proposing natural selection as the MECHANISM 
of evolution.  Probably the most well known (to us today) anyway 
alternative around before that was Lamarkism.  Of course, today we have 
people suggesting that God controls evolution, apparently replacing 
natural selection with divine intervention as the main driving force of 
evolution.  

>    and I thought I read that the gradualist model was challenged in favor of
> a "punctuated" model in the 19th century as soon as the gradualist model was
> proposed.

     Before evolution was a well accepted idea, one of the big ideas to 
explain the fossil record and its obviously extict forms, as well as new 
species popping in apparently out of knowhere, was Catastrophism.  
According to this theory, history was punctuated by several 
catastrophies (I can't remeber if they were all floods or not) that wiped 
out existing species, each followed by a brand new creation.  Cuvier was 
a big fan of this theory (an an opponent of evoltuion).  In the 19th 
century, when Hutton and Lyell came up with uniformitarianism (sp?), geologic 
history in general and evolution in particular began to be seen as a 
gradual, uniform process.  In the 70s or 80s (can't remember), Steven J. 
Gould and Niles Eldridge (sp?) came up with the theory of punctuated 
equilibrium, which says that evolution is mostly stasis, with brief 
periods of explosive speciation.  Today it is largely accepted that 
uniformitarianism is not always the case, and that things in the geologic 
past sometimes happend differently and at different rates than they do 
today.  This merging of unifromitarianism and catastrophism (using the 
term loosely in light of its previous biblical connotations) is called 
ACTUALISM.    
        
LN Jeff
 
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