"TomHendricks474"  wrote in message
news:bari31$5js$1{at}darwin.ediacara.org...
>  wrote:
> > I contend that due to my model, no species 'evolves'
> > unless they are forced to adapt to harsh changes - thus
> > As environmental adaptation increases:
> >    directional and diversifying selection decreases
> >    AND stabilizing selection increases.
> >     (and vice versa)
> > So I contend that the brain development in hominids
> > was due to the harsh environmental weather at the time:
> > 
> I am not knowledgeable enough on hominid brain development (even my
> own) to comment much, but as an interested amateur, I would take issue
> with your first sentence in the use of the word "harsh" and
the ubiquitous
> and generalized nature of the statement.  I would suggest that species'
> evolution (or alternatively, reduction or extinction) is almost assured by
> harsh changes, but that many other factors may also be a catalyst for
> evolution.  Chief among these would be simple advantage over other
> species and ancestor of a species in question.  This could be any or all
> of issues like higher reproductive rates, easier access to unexploited
> food sources, improved mobility, better sensory organs and processing,
> and many others items which could improve a species change to thrive,
> even in a relatively stable environment (i.e. nothing externally
"harsh"
> like weather, predators, and so on.)
>
> TH
> I agree that all your examples will make modest improvements,
> but I am talking about the major brain spurts of this specific time.
> You seldom have drastic changes in stabilizing selection.

Well, you may have been "talking" about that, but your writing stated:

>TH: "I contend that due to my model, no species 'evolves'
> unless they are forced to adapt to harsh changes - thus
> As environmental adaptation increases:
>  directional and diversifying selection decreases AND
>   stabilizing selection increases.
>    (and vice versa)"

and t'was that to which I specifically responded.  Regards, Brett.  
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