Low Cost Bology Experiments

[rblgw]

I am in the process of developing a workshop for biology teachers (grades
3-12).  The object is to try and bring back the bios in biology.  Since I 
am doing this in Louisiana, one can expect the budget for biology teachers 
to be almost zero.  I have several experiments lined up but am looking for 
more.  I would like the experiments to meet the following criteria: 

1) They should be relatively simple to do (not require any unusual 
equipment).

2) Incorporate living material to explain biological concepts.

3) Be inexpensive to setup.  

I would appreciate any and all suggestions.

Dr. R. N. Bortnick
Louisiana State University - Alexandria