BASC Office Temporarily Closed — All Advising Services Virtual

Due to a scheduled remodel, our physical location will be closed until winter quarter. Our team will continue to provide all services virtually to ensure uninterrupted support of our students. You can connect with us through virtual advising appointments, virtual express advising, and email at cbsundergrads@ucdavis.edu.

Equivalency Guidelines for the BIS2 and BIO123 Series

The College of Biological Sciences is updating the lower division core biology courses at UC Davis to improve STEM curricula. Replacing BIS 2A, 2B, and 2C, the BIO123 Series will be required for all students in the College of Biological Sciences who have not yet begun their Introductory Biology coursework. The new series has been modernized to improve the curriculum and offer more flexibility for students. The BIO 123 series will be available starting Fall 2025.

For CBS students who have already started the BIS 2 series, it will be available for the 2025-2026 academic year. Please plan to complete the BIS 2 series if you have taken any course in the series. 

For students outside of the College of Biological Sciences, we recommend that you connect your major advisors to identify whether the BIS 2 series or the BIO series is appropriate.

Equivalency Guidelines

In general, the following can be considered equivalent:

  • BIO 1 + 1L will be equivalent to BIS 2B.
  • BIO 2 will be equivalent to BIS 2A.
  • BIO 3 or BIS 70 will be considered equivalent to BIS 2C in terms of completing the introductory biology series.
    • Note: BIS70 and BIO3 do not have a lab component.  Therefore, pre-professional students needing intro bio with lab would need to take BIO 2L to get a second lab course. This would require the consent of the instructor.
  • Special note for majors also requiring BIS 2D: BIS 2D will not be offered starting Spring 2026. Students can take BIO 3 instead of BIS 2D to fulfill requirements. 

For students who have started the BIS 2 series, you should try your best to complete the series. However, if you need to mix and match, follow the guidelines below.

Here are the main likely scenarios a student could face:

For students who have taken BIS 2A but did not take 2B or 2C, they can take:

  • BIS 2B or (BIO 1 + BIO 1L)
  • BIS 2C or BIO 3 or BIO 70
    • BIO 1 & BIO 2 are pre-reqs for BIO 3. Therefore, you will be required to submit a pre-req petition if you have taken BIS 2A.
    • Pre-professional students needing intro bio with lab would need to take BIO 2L to get a second lab course.
    • All CBS majors and many other majors on campus also require BIO 2L.

For students who have taken BIS 2B but did not take BIS 2A or 2C, they should take:

  • BIS 2A or BIO 2
    • BIO 1 is a pre-req for BIO 2. Therefore, you will be required to submit a pre-req petition if you have taken BIS 2B.
  • BIS 2C or BIO 3 or BIO 70
    • BIO 1 & BIO 2 are pre-reqs for BIO 3. Therefore, you will be required to submit a pre-req petition if you have taken BIS 2A.
    • Pre-professional students needing intro bio with lab would need to take BIO 2L to get a second lab course.
    • All CBS majors and many other majors on campus require BIS 2L.

For students who have taken BIS 2A and BIS 2B but not BIS 2C, they should take:

  • BIS 2C or BIO 3 or BIO 70
    • BIO 1 & BIO 2 are pre-reqs for BIO 3. Therefore, you will be required to submit a pre-req petition if you have taken BIS 2A and BIS 2B.
    • Pre-professional students needing intro bio with lab would need to take BIO 2L to get a second lab course.
    • All CBS majors and many other majors on campus require BIS 2L.

For students who took BIS 2B and 2C, but not BIS 2A, they should take:

  • BIS 2A or BIO 2
    • Note: these students do not need to take BIO 2L because they will have already had 2 quarters of lab from 2B and 2C.

For students who have taken BIS 2A, BIS 2B, and BIS 2C AND require BIS 2D, they should take:

  • BIO 3

For students who have taken BIS 2A and BIS 2B and need to take both BIS 2C and BIS 2D, they should take:

  • BIO 3 and BIO 2L