skip to main content
Home  /  Academics  /  Biology  /  Courses  /  First-Year Biology

First-Year Biology

Caltech's First-Year Biology Requirement

Biology is one of the most exciting and impactful disciplines of the 21st century and at Caltech. From investigating how complex organisms develop from a single cell, to understanding the neurobiology of emotion, to recognizing the critical role microbes have played and continue to play in shaping and sustaining our planet, to coming up with new ways to control viruses, biology offers something fascinating for everyone regardless of primary major.  Indeed, some of the greatest opportunities for discovery and applications lie at the interface of biology with other disciplines. Accordingly, All Caltech students are required to take 9 units of first-year biology, which can be satisfied by taking any course numbered Bi 1. Several different course options are available, with each Bi 1 course representing a different approach to providing an introductory understanding of the biological sciences. All Bi 1 courses may be taken pass/fail if they are taken in the freshman year, independent of the term in which the course is taken. For students who are interested in the fundamentals of eukaryotic molecular and cellular biology, the freshman biology requirement can also be satisfied by completing both Bi 8 and Bi 9.

This page provides information on the different options available to students and gives guidance on how to choose the Bi 1 course that is best for you.

Bi 1 and the Core

Caltech's core curriculum is designed to provide all Caltech undergraduates with the scientific background that they need to understand the world around them and to pursue studies in any of the disciplines in which Caltech offers a degree. A basic understanding of biological principles is an integral part of a Caltech student's scientific education. Thanks to our small size and creative approach to science and instruction, we are able to teach fundamental principles of Biology in a variety of ways that tap into the interdisciplinary strengths and interests of our faculty.

Bi 1 is designed to provide insights into modern biology in a manner that provides students insights into fundamental biological mechanisms and how to understand the biological world. Core concepts such as the nature of the cell, gene expression and regulation, evolution and mutation, and energy conservation and metabolism are unique to the biological sciences and provide the starting points for understanding the biological world, with applications ranging from human health to the global environment to biotechnology.

2023-24 First-Year Biology Course Offerings

For academic year 2023-24, there are five different Bi 1 courses available.

Winter 2024

Professor Lior Pachter

Bi 1c. Biology Through the Algorithmic Lens
9 units (3-0-6); second term. Do biological systems compute? Can we compute with biological systems? Is computer code a meaningful metaphor for genetic code? Do neural networks in biology have much to do with neural networks in computer science? In this class we will investigate these and other questions with a view towards learning about deep connections between biology and computer science that shed light on fundamental questions in biology. May be taken pass/fail if taken in a first-year student's first year. Instructor: Pachter

Professor Ellen Rothenberg

Bi 1i. Construction and Guidance of Biological Defense
9 units (4-0-5); second term. We are bombarded by biological threats from the outside, ranging from toxic particulates to epidemic viruses, and also by threats from within, like cancer.  How do our bodies manage to be victorious against these threats for so many years, in most cases?  Many people have some familiarity with aspects of the answers now, due to COVID-19.  But how can these defense mechanisms actually work, and how can they coordinate their actions to be effective and safe?  Why do they fail?  This course will zoom between scales to introduce the cells that the body uses for immune defense and how they execute their roles, both system-wide and at the molecular level.  A central theme will be how the system is controlled by cellular "software" reading the genetic code, by ultra-rapid evolutionary mechanisms, and by elegant cell-cell communication networks.  Lectures and student presentations will be included.  May be taken pass/fail if taken in the freshman year. Limited enrollment. Given in alternate years; offered 2023-24. Instructor: Rothenberg

Spring 2024

Professor Rob Phillips

Bi 1. The Great Ideas of Biology
9 units (4-0-5); third term. Biological processes take place at length scales ranging from that of individual protein molecules all the way to the algal blooms or rainforests that can be seen from space and over a dizzying nearly 30 orders of magnitude in time scales. This course will start by examining the biology of processes such as how plants and animals colonize oceanic islands and the physics of how animals such as wildebeest form giant herds during their year-long migration. With these wonders of the living world revealed, we will then seek to understand biological phenomena by thinking about genes and cells. May be taken pass/fail if taken in a first-year student's first year. Instructor: Phillips

Professor Michael Dickinson

Bi 1b. The Biomechanics of Organismal Design
9 units (3-0-6); third term. Have you ever wondered how a penguin swims or why a maple seed spins to the ground? Can a flea jump as high as a kangaroo? Is spider silk really stronger than steel? This class will offer answers to these and other questions related to the mechanical design of plants and animals. The course will provide a basic introduction to how engineering principles from the fields of solid and fluid mechanics may be applied to the study of biological systems. The course emphasizes the organismal level of complexity, although topics will also connect phenomenology at the molecular, cellular, and tissue-level scales. The class is explicitly comparative in nature and will not cover medically-related biomechanics. Topics include the physical properties of biological materials, viscoelasticity, biological pumps, muscle mechanics, neural control, and animal locomotion. May be taken pass/fail if taken in the freshman year. Limited enrollment. Instructor: Dickinson

Professor Justin Bois

Bi 1 x. The Great Ideas of Biology: Exploration through Experimentation.
9 units (0-6-3); third term. Introduction to concepts and laboratory methods in biology. Molecular biology techniques and advanced microscopy will be combined to explore the great ideas of biology: the cell, the gene, evolution by natural selection, and life as chemistry. This course is intended for nonbiology majors. May be taken pass/fail if taken in a first-year student's first year. Limited enrollment. Instructor: Bois

Frequently Asked Questions

Biology can be studied from many different points of view and it is not possible to cover everything in a single 10 week course. You should look through the course description and try to find a course that has topics or a perspective that particularly interests you. Any of the courses listed here will provide you an outstanding introduction to the biological sciences and provide an opportunity to learn what makes the biological sciences so interesting and special.

Yes!  While sometimes biology is taught well in high school, unfortunately it often emphasizes memorization and/or teaches to the AP test, which is not inspiring. Our Bi1 offerings are distinct in both mode of instruction and content.  You have the opportunity to take something completely different from what you took in high school by selecting the Bi1 option that most excites you.  Biology is a huge subject, and even if you had a good course in high school, there is undoubtedly much you have yet to learn that will amaze you.

It is also possible to satisfy the Caltech first-year Biology requirement by taking Bi 8 and Bi 9. Bi 8 and 9 are required for Biology majors, and focus on eukaryotic molecular (Bi 8) and cellular (Bi 9) biology.

We offer a variety of first-year "informational courses" that meet for 1 hour each week and provide an introduction to different topics that Caltech faculty are pursuing in their research. These courses can give an overview of some of the areas of specialization and research that biologists and bioengineers study, and the lectures are designed to tell you more about what it is like to major in bioengineering or biology.

  • BE 1. Frontiers in Bioengineering. 1 unit: first term. A weekly seminar series by Caltech faculty providing an introduction to research directions in the field of bioengineering and an overview of the courses offered in the Bioengineering option. Required for BE undergraduates. Graded pass/fail. Instructor: Staff.
  • Bi 2. Current Research in Biology. 3 units (1-0-2): first term. Intended for students considering the biology option; open to freshmen. Current research in biology will be discussed, on the basis of reading assigned in advance of the discussions, with members of the divisional faculty. Graded pass/fail. Instructor: Elowitz.

You can also talk to the undergraduate option representatives to learn more about our programs:

Yes! Caltech's offers undergraduate minors in Biology or Neurobiology. Students who minor in one of these options will typically a few required courses that go beyond the first-year biology requirement and then select from a variety of upper-level courses.

Caltech offers many ways for undergraduates to get involved in research in biology and biological engineering. Many Caltech undergraduates take advantage of Caltech's SURF program, in which undergraduates work with a faculty member (and often graduate students and postdocs) to write a proposal for a research program that is carried out during the summer. Faculty in the Division of Biology and Biological Engineering host many SURF students in their labs over the summer and there are ample opportunities available. For more information on pursuing a SURF project, see Caltech's SURF homepage.

Research during the academic year is also possible and it is common for juniors and seniors in Bioengineering and Biology to carry out research as part of their studies, including the option to pursue a senior thesis. Courses that can be used to get academic credit for carrying out research during the academic year include:

  • Bi 21. Undergraduate Research with Presentation. Minimum 12 units per term (0-11-1); first, second, third terms. Special problems involving laboratory research in biology; to be arranged with instructors before registration. Must give a public presentation reporting results of work. May be counted as advanced lab credit. May be repeated for credit.
  • Bi 22. Undergraduate Research. Units to be arranged; first, second, third terms. Special problems involving laboratory research in biology; to be arranged with instructors before registration. Graded pass/fail.
  • Bi 90 abc. Undergraduate Thesis. 12 or more units per term; first, second, third terms. Prerequisites: 18 units of Bi 22 (or equivalent research experience) in the research area proposed for the thesis, and instructor's permission. Intended to extend opportunities for research provided by Bi 22 into a coherent individual research project, carried out under the supervision of a member of the biology faculty. Normally involves three or more consecutive terms of work in the junior and senior years. The student will formulate a research problem based in part on work already carried out, evaluate previously published work in the field, and present new results in a thesis format. First two terms graded pass/fail; final term graded by letter on the basis of the completed thesis.
  • BE 98. Undergraduate Research in Bioengineering. Variable units, as arranged with the advising faculty member; first, second, third terms. Undergraduate research with a written report at the end of each term; supervised by a Caltech faculty member, or co-advised by a Caltech faculty member and an external researcher. Graded pass/fail.
  • BE 99 abc. Senior Thesis in Bioengineering. 6 or more units per term with a three-term total of at least 27 units; first, second, and third terms. Prerequisites: Junior or senior standing and instructor's permission. Research in Bioengineering, supervised by a Caltech faculty member, culminating in a thesis. The topic is determined by the research adviser and the student and is subject to approval by the Bioengineering faculty. The first and second terms are taken pass/fail and require a written report at the end of each term. The third term is taken on grades and requires completion of a thesis and final presentation. The last two terms must be completed in the final year of study. Total units arranged with the advising faculty member.

There are a lot! At Caltech, you can find a list of the areas were faculty are actively pursuing research on the BBE Research webpage. At a high level, the major areas represented at Caltech include: