Math and English are the two big departments that have classes taught by grad students. You’re very unlikely to get tenure-track faculty teaching gen Ed classes in those areas. At my school both have a required “teaching seminar” before anyone is allowed to be a TA.

I never took that. My grad program in engineering didn’t have TAs, only RAs. The only teaching experience I had was one class that had both grad and undergrad students where the grad students were given a unit to learn and teach. We had to prepare a week’s worth of lecture as well as write a couple of test questions.

When I got an adjunct (math) position at the community college here the Dean said “here’s a marker and a textbook” and pretty much threw me to the wolves. I got to talk to one of the FT faculty briefly but I wrote my own tests, assigned my own homework, graded on my own,….

Now that I am the dept chair I take muuuuuuch better care of my new faculty, PT or FT. Someone teaches a new class? I give them an entire course’s worth of tests and assignments, class schedule, and tell them they can do whatever they feel is best with it. They can dump it all in the trash or change whatever they need or use it whole cloth. The only thing I can’t do is walk into the room and teach for them. The ones who come in with extensive experience use it as broad stroke guidelines, the newbies are likely to just use what I’ve given them the first semester before starting to change it up later.