The areas of Biology, Chemistry and Physics are closely related. No matter what major you choose, you will most likely take classes in the other two disciplines.
Students say that the small departments enhance their learning.
For one thing, classes are rarely composed of students in a single major. That brings more perspectives to the material. So, even when you are not in the classroom, there is still a lot of learning going on because of that. I think that is an advantage over a big university where you would probably be interacting with students in your own major. The small departments also insure that students get more interaction with their professors.