Some of my colleagues and I are divided on a particular issue related to the teaching of undergraduate Science classes for majors. I am talking about the "core" classes that we teach our Science majors: the courses that cover the designated most essential topics in our Science. In most departments, faculty typically teach the core courses closest to their area of research expertise, and perhaps some courses that are sort of related.
CAMP 1. Some of my colleagues think that any one of us could teach any one of these classes. We have all taken these or similar classes as undergraduates, and even though we may not have studied certain topics since that time, we are smart people with broad knowledge of Science and we could each learn enough to teach any undergraduate course in our department.
CAMP 2. Other colleagues think OK, we could teach these courses.. if we had to.. but the courses would not be good because we would not be able to provide the depth of experience that can make a course successful and interesting. Perhaps there are some instances in which a non-specialist approach or perspective would benefit a course (and certainly there are examples of the opposite case in which a specialist of a topic is unable to teach a course well), but in many cases we wouldn't be able to provide much more information than what a smart student could teach themselves by reading a textbook.
I am more in Camp 2 than Camp 1, and I don't think it is just because I live in fear of being asked to teach a course that would require a vast amount of preparation on a topic for which I do not have deep knowledge. I don't mind being outside my comfort zone in terms of knowledge and I love learning new things, but I still don't want to run the experiment to test whether the Camp 1 people are right.
At small colleges, faculty teach a wider range of classes because there are fewer faculty to teach the core classes. That's fine -- I did the same when I taught at a college -- and I am not arguing that we can only teach (well) those courses most directly related to our specific research focus. But I think there are limits to what most of us can reasonably teach well with sufficient depth of knowledge to handle challenging questions, use supporting examples beyond what is in textbooks, and keep up with the latest developments in the field.
Maybe those things aren't important. Those in Camp 1 would argue that we could each master the fundamental concepts of each core class and be able to teach those. OK, sure, we can do that, but again I ask: Would the classes be any good?
This is mostly just a thought exercise, at least at the moment. If hiring freezes continue, however, we may find ourselves in a situation in which core courses need teaching, but the core people have left and not been replaced.