BIO123 Administrative Information

The BIO123 Series is UC Davis’s introductory biology curriculum, administered by the College of Biological Sciences and serving thousands of undergraduate students from majors across the university. The yearlong series provides a modern foundation in the life sciences through integrated lecture, discussion, and laboratory experiences. Designed to reflect the interdisciplinary nature of contemporary biology, the curriculum emphasizes scientific thinking, hands-on learning, data analysis, and the process of scientific discovery.

Faculty Leadership

Smiling man in blue plaid shirt, outdoor portrait with blurred autumn foliage

Jay Stachowicz

Faculty Director for BIO123 Series
Distinguished Professor of Evolution and Ecology

BIO123 Series Schedule of Offering

The BIS2 series will no longer be offered after Summer 2026. Starting Fall 2026, the BIO123 Series will be offered every quarter. After Summer 2026, if you have taken part of the BIS2ABC series, please see the equivalency guidelines for the BIS2 and BIO123 Series page. 

A simple infographic showing the timeline of the new course rollouts

*In fall 2025, BIO1 and 1L will be open only to incoming CBS freshmen during first pass. If you have questions, please contact your major's academic advisor. 

Information about Transition and Cancellation of BIS2 Series

The introduction of the BIO123 Series will result in the eventual cancellation of courses in the BIS2 series. If you currently require BIS2A, B or C in your major's curriculum, or as a prerequisite for one of your courses, please use the collected BIS2 series syllabi to familiarize yourself with their content.

CBS is working with the Academic Senate to streamline the process for majors to transition between the BIS2 series and BIO123 and will post this information as it becomes available. As of May 2025, the Undergraduate Council has approved an expedited review process. For more information, please see the Process for expedited approval of inclusion of BIO 1, 2, 3, 1L, 2L courses PDF. 

For Students in the BIS2 Series

The best option for students who have started the BIS2 series is to complete the BIS2 series. However, we recognize some students may need to substitute BIS2 courses with those in the BIO123 Series. Please work with your major advisor to determine which substitutions meet your individual needs. 

Attention students: you must get approval from your major's academic advisor before making any course substitutions to the BIS2 series.

How Do I Add BIO123 Courses as Prerequisites Using ICMS?

Overview

Instructors should add the new BIO123 courses as options rather than replacing existing BIS2 prerequisites. For example, if a course requires BIS2B, add BIO1 as an option so that the catalogue reads "BIS2B or BIO1." This will accommodate students who have taken courses in either series. You can do this yourself if you have ICMS access. If you do not have ICMS access, you will need to contact your department's instructional support staff. 

Getting Started

To add the new BIO courses as a prerequisite from an existing course, submit a Prerequisite/Restrictions ICMS proposal. If this is the only change to be made, make sure to use this proposal type for a quicker processing time.

A dropdown menu labeled "Proposal Type" is open, displaying various options related to course proposals. The highlighted selection is "Colleges Prereq/Restrictions - Undergrad." Other visible options include new course proposals and course discontinuations for graduate, professional, and undergraduate levels.
Course Information Tab

You will need to enter the effective term for the change and fill in the remarks box. A sample for BIS 101 is below. 

A form section displaying "Effective Term *" set to "2025 Fall Quarter" with a dropdown menu. Below, a bold instruction reads: "Remove previous remarks. Summarize the changes being proposed and the reason(s) for these changes." In the "Remarks *" text box, the entry states: "Adding new Bio1 and Bio2 as options for existing prerequisites. BIS2B or Bio1; BIS2A or Bio2."
Prerequisites Tab

To add the appropriate BIO123 Series course(s) as prerequisites takes two steps. First, you will need to remove the existing BIS2 series course(s) from the prerequisite list, then re-enter it with the condition “or.” Second, you will add the new BIO123 Series course(s).

You can see a sample from BIS 101 below. Note the logic: ((BIS002A C- or better) or (BIO002 C- or better))

A "Prerequisites" section listing **BIS 002A (Active)** and **BIO 002 (In Review)** as options, both requiring a **minimum grade of C-**. The entries are enclosed in parentheses with an "or" condition. Options to adjust or remove each entry are present, along with a selected "Show Details" checkbox and an "Add Item" button.

At the bottom of this page, make sure to review the Prerequisite Catalog View box to make sure it reads correctly. This is what students and advisors will see. See BIS 101’s sample below.

Alt text: A "Prerequisite Catalog View" box listing multiple prerequisite options. Courses include **BIS 002A or BIO 002 (C- or better), BIS 002B or BIO 001 (C- or better), CHE 008A, CHE 118A, or CHE 128A, and statistics options (STA 013, STA 013Y, STA 100, STA 102, or STA 130A)**. **STA 100 is preferred.**
Approvals

The department and college course committees will review and, if approved, the proposal will go directly to the team that adds to the catalog course list. 

Additional FAQs

  • Why are we making these changes now?
  • The new course series enhances small-group discussions, hands-on labs, and active learning to better prepare students for upper-division coursework. By focusing on core concepts and practical skills, the updated series allows for greater mastery and retention while maintaining a strong foundation in biological sciences.
  • How does the structure of the BIO123 Series compare to that of the BIS2ABC series?
  • The new BIO123 Series must be taken in sequence and separates lectures and labs into standalone courses (e.g., BIO1 and 1L). Lecture courses are now 4 units (3 units of lecture, 1 unit of discussion), while labs are optional 1-unit courses which can be taken concurrently with the lectures. This structure facilitates small-group discussions, active learning, and scheduling flexibility while reducing the overall series by 1 unit.
  • What about BIS2C, Introduction to Biology: Biodiversity and the Tree of Life?
  • Key topics from BIS2C are distributed across the series. BIO1 covers the basics of phylogenies and major evolutionary innovations. BIO2 addresses the evolution of unicellular life and distinctions among bacteria, archaea, and eukarya. BIO3 highlights functional biology and adaptations in multicellular organisms (plants and animals) without systematically covering all organismal diversity. A broad survey of the diversity of life will still be available in the new 3-unit BIS 070 lecture course (Biodiversity and the Tree of Life), which will be offered after BIS2C is discontinued. 
  • How do I know if a course has BIS2A, BIS2B or BIS2C as a prerequisite? 
  • To see if a BIS2 series course is a prerequisite for one of your courses, review the ICMS impact report for each respective course. This report will also indicate which majors and minors have these courses listed under program requirements.
    BIS02A Impact Report
    BIS02B Impact Report
    BIS02C Impact Report
  • How will these changes influence prerequisites for upper-division courses?
  • Departments will determine which of BIO1, BIO2, or BIO3 align with their course prerequisites. For courses that previously required BIS2ABC or a full-year biology introduction, the BIO123 Series is recommended. Departments looking for broader coverage of organismal diversity across all life should consider requiring BIO70. 
  • How will the new series articulate with community college biology courses?
  • In the short term, community college courses will continue to articulate into the BIS2ABC series. Over the next two years, CBS will work with community colleges to develop new articulation agreements for the BIO123 Series. In the longer term, the BIO123 Series is expected to articulate more easily with most community college courses than the current BIS2ABC series.