I'm not entirely sure, but I think the average required to transfer into a program is the same as entering the program normally.
For Hons. Life Sci (4 yrs), the entrance average to Level II is 6.0. The requirements for entry are here:
http://registrar.mcmaster.ca /calen...nt/pg1957.html . I believe that if you have most or all of the prereqs (there really aren't a lot), you should be able to transfer directly into Level II, and possibly make up any missing credits in summer school.