Evolutionary Advantage?

[M. Jane Harper]

I'm not sure this question fits in *any* BIONET section, but it came up in
my neuro course, so here goes ...

Can anybody explain what evolutionary advantage may lie in manufacture of
neuropeptides my subtraction?  That is, why make a B  I  G     L  O  N  G
peptide and then whack off little pieces of it until Mama Nature gets 
what she needs?  Is there an evolutionary advantage?  If so, what?

Here endeth my wise-*ss question of the week.  Thanks in advance.

Jane Harper
Doctoral Student, Neuroscience/Nursing
University of California at San Francisco
jharper at itsa.ucsf.edu