There isn't one, except in the context of what each person plans with an advisor from semester-to-semester. There are many reasons why just one academic plan doesn't work for everyone. Students often have such disparate backgrounds of academic, personal and work experiences, each person's undergraduate course plans have to be custom-made. This is especially true for those entering the program with advanced placement from high school courses, transfer credits from colleges or other universities, or waiver status based on competency testing at the time of initial enrollment in the university.
Also, there are different professional training goals. What is a useful curriculum plan for someone considering applying to medical school, might well be different from that of someone interested in graduate school, or someone else wanting to enter the job market right after graduation. Despite the apparent lack of common structure in the course sequence for each student, most get the best from our program by working with faculty and staff not only to tailor an academic plan as soon as possible, but also to modify it as frequently as necessary as they progress toward graduation.
There is considerable variation among plans to take required courses and electives. An important guiding rule, however, is imposed by the fact that many courses have prerequisites. The Michigan State University publication, "Description of Courses," lists not only course prerequisites, but also a short description of each course, when they are offered and who is eligible to enroll in them. Another guiding rule is the academic load that each person judges to be comfortable from semester-to-semester. Deciding on the number of credits for a semester in balance with the nature of the courses is best completed, of course, with the help of an advisor.