TeenHelp - How many hours per unit can be expected for homework in a Biology BS?

It depends a lot both on the friends you have, the professor, the amount of understanding you have and other courses. For all the third-year biology courses I did (2 only) I spend tons of time but that was because they were ridiculously difficult. In my second year, it varied a lot. One of the second-year biology course I spent little time studying while for another one I spent a bit more and another one I spent hours on end. It varies a lot. Also, not all biology courses have labs or tutorials. One of the third-year biology courses I'm going to do has no labs, only lectures. Another third-year biology course I'm considering to do as a back-up has labs off-campus at research facilities in addition to lectures and labs on campus. Some people have a better grasp for genetics while others don't so you have to first see for yourself what your strengths and weaknesses are.

Your planning will be affected by other courses you are taking because those may be harder.

For homework, the same varies. For the evolution course, the only way anyone could manage to pass it is if we came into the labs after hours and spend at least 3 hours there, so for that course I have no idea how long I spent on it. This was almost daily for me and many others. Over 40 hours for this course, not sure what the total amount was though.

For one of my first-year biology courses, the labs were optional because there were no lab reports. All you did was sketch the organisms through the microscope, jar or whatever they were in, in hopes to identify key features for bell-ringer tests (don't want these, they can be utter hell).