cortical-spinal conections

[Stephen Lessnick]

I have recently been asked to find info on the following, but have not 
been particularly successful.  Does anyone have information regarding:

1)  Why (from a teleological {sp?} point of view) does the right 
hemisphere control (and receive information predominantly from) the left 
side of the body and visa-versa?  I'm sure there have been a number of 
theories advanced.  If you have references for the theories it would be 
really helpful.

2)  When in evolution does this pattern of crossed connections arise?

Thanks!