Since you are asking this question on the Drury University page, I will assume that you are interested in teaching in missouri. There is a mahalo page on this very topic How to Become a Teacher in Missouri (http://www.mahalo.com/how-to-become-a-teacher-in-missouri).

Generally speaking, you have to have an undergraduate degree, get a teaching certificate, and get fingerprinted. There are alternate routes to the teaching certification but you do have to have that undergraduate degree to pursue them as well. As such, you'll have to take those other courses that you mentioned though if you are a biology major, you will only take a few of the other sciences. They all work together, however. You can't know biology and not know some chemistry and some physics. They are all interrelated.

Once you get to the teaching part though, you will not be asked to teach the other courses because you will not be certified to teach those (assuming that you get your teaching certificate in biology). Teaching certificates beyond elementary and middle school are often subject specific. Some states even require you to take a subject area test to get your certification.

Good luck.

Edit: If you want to teach in another state but go to Drury University, you should check out the requirements for teaching in the state you wish to live in.

You actually just need a degree period. Ideally a degree in Biology would be great but depending on the grade level and where you want to teach (there is a huge need for teachers in certain areas where they overlook it), they will train you in whatever teaching program you enter on the subject. However, a degree in Biology means you take a ton of upper level chemistry and physics classes as well.