Five researchers in lab coats and safety goggles gather around a microscope in a laboratory. One person is looking into the microscope while others observe and smile, surrounded by shelves and lab equipment.
BIO123 Series

New Introductory Biology Courses and Labs for UC Davis

The College of Biological Sciences is revamping core biology at UC Davis to enhance STEM curricula. Replacing BIS 2A, 2B, and 2C, the BIO123 Series focuses on adaptation, heredity, ecology, evolution (BIO1); metabolism, DNA structure, and cell biology (BIO2); and challenges of multicellular life with evolved adaptations (BIO3). Optional labs BIO1L and BIO2L, now separate, emphasize inquiry-based approaches and multi-week projects for hands-on experience in biological techniques and hypothesis testing.

Evolution and Ecology

BIO1 Lecture and Discussion

BIO1L Lab

Molecules to Cells

BIO2 Lecture and Discussion

BIO2L Lab

Cells Through Organisms

BIO3 Lecture and Discussion

What's Changing

The BIO123 Series curriculum is designed to enhance student learning through an integrated and conceptual approach. The updated structure emphasizes hands-on experiences, problem-solving, and real-world applications, fostering deeper engagement with the life sciences. Some of the most notable changes include:

BIO123 Lectures

Sequencing of the courses will allow for improved student success as study skills and topics mastered in one course can be built on in subsequent courses. Topical themes can be connected and reinforced across the sequence, connecting to practical problems such as climate change, human health, and biodiversity conservation and ecosystem management.

BIO 1L and 2L 
  • Creation of a sequenced lab series that can be taken concurrently with BIO1 and BIO2 (2 additional units):
  • These courses have hands-on, hypothesis-driven, inquiry-based laboratory activities that meet 2.5 hours/week.
  • Their goal is to grow a student’s scientific mindset and build a more intuitive understanding of the molecular and biological world, and to enhance their ability to formulate and test hypotheses using current techniques in molecular and cellular biology, ecology, evolution and biodiversity.

Recommendation for Majors Requiring BIS2ABC

For majors that require a full year of introductory biology, we recommend that students take all five courses in the BIO123 Series, including BIO1, 2, 3 and both BIO1L and 2L, totaling 14 units. Alternatively, the new structure allows departments to require the BIO1, 2, and 3 lecture courses without the BIO1L and 2L lab courses, affording two units of flexibility for major-specific instruction.

Replacing BIS2ABC Courses with BIO123 Courses and Labs

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 BIS2ABC syllabi to familiarize yourself with their content. 

Currently, there are five scenarios where BIS2 courses represent instances where the change to the BIO123 Series will require substitutions to fulfill the prerequisite or major requirements:

  • If only BIS2A is required

  • If only BIS2A is required, we recommend one of the following two options:

    Take BIO2 lecture (4 units). If lab component is desired, add BIO2L (1 unit). Note that BIO2 has a prerequisite of BIO1 (4 units). BIO2L has a prerequisite of BIO1L (1 unit).

    OR

    Take BIS 010 – Everyday Biology (4 units).

  • If only BIS2B is required

  • If only BIS2B is required, we recommend the following replacements:

    Take BIO1 lecture (4 units). If lab component is desired, add BIO1L.

  • If both BIS2A & BIS2B are required

  • If both BIS2A and BIS2B are required, we recommend the following replacements:

    Take BIO1 lecture (4 units) and BIO2 lecture (4 units).

    If lab component is desired, take BIO1L (1 unit), and BIO2L (1 units). Note that BIO1L is required for BIO2L.

  • If both BIS2B & BIS2C are required

  • If both BIS2B and BIS2C are required, we recommend the following replacements:

    To replace BIS2B, Take BIO1 (and 1L if lab desired). 

    To replace BIS2C, take either BIO3 or BIS70 or other non-CBS courses to be listed here as they are identified. Note that if BIO3 option is selected, BIO1 and BIO2 will also be required since they are prerequisites.

Syllabi of Potential Replacement Courses*

*This folder is populated with options within CBS, such as the new courses and labs in the BIO123 Series, as well as other CBS-administered courses, like BIS10 and BIS70. As various departments identify substitutions, we will update the pages above to include their recommendations. 

How Do I Add BIO123 Courses as Prerequisites Using ICMS?

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. 

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 do I add the new BIO123 Series courses as prerequisites?
  • Please see the detailed information in How Do I Add BIO123 Courses as Prerequisites Using ICMS? Note: 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. 
  • 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.