Re: More tyrant Q & A's

["Norton, Patrick" <Patrick.Norton@state.me.us>]

Stan Friesen  wrote:

>On ecological grounds, forms that co-occur in one time-place can really   
only be distinct species if they differ sufficiently to be able to   
minimize competition.<

Many highly competitive, morphologically similar species have territories   
that overlap to some extent for one reason or another.  _Canis lupus_ and   
_Canis latrans_ , for example, co-exist across broad ranges of Canada and   
the US, probably due to a gradual process of displacement.  Several   
species of _Sciuris_ (also highly competitive and morphologically   
similar) co-occur in the forests of the northeast.  I think that, over   
time, in a stable environment, minimization of competition would   
naturally among the inhabitants.  But I'm not sure it's safe to assume   
that morphologically similar Tyranosaurid species found in the same   
paleoenvironment were engaged in only minimal competition.