Ge 104. Introduction to Geobiology. 9 units (3-0-6); second term, 2025-26. Prerequisites: instructor's permission. Lectures about the interaction and coevolution of life and Earth surface environments. We will cover essential concepts and major outstanding questions in the field of geobiology, and introduce common approaches to solving these problems. Topics will include biological fractionation of stable isotopes; history and operation of the carbon and sulfur cycles; evolution of oxygenic photosynthesis; biomineralization; mass extinctions; analyzing biodiversity data; constructing simple mathematical models constrained by isotope mass balance; working with public databases of genetic information; phlyogenetic techniques; microbial and molecular evolution.
Instructor: Tejada

Ge 11 b. Introduction to Earth and Planetary Sciences: Earth and the Biosphere. 9 units (3-3-3); second term, 2025-26. Prerequisites: Ch 1 a. Systematic introduction to the origin and evolution of life and its impact on the oceans, atmosphere, and climate of Earth. Topics covered include ancient Earth surface environments and the rise of atmospheric oxygen. Microbial and molecular evolution, photosynthesis, genes as fossils. Banded iron stones, microbial mats, stromatolites, and global glaciation. Biological fractionation of stable isotopes. Numerical calibration of the geological timescale, the Cambrian explosion, mass extinctions, and human evolution. The course usually includes one major field trip and laboratory studies of rocks, fossils, and geological processes. Although Ge 11 abcd is designed as a sequence, any one term may be taken as a standalone course. Biologists are particularly welcome.
Instructor: Tejada

Ge/Bi 244. Paleobiology Seminar. 6 units (3-0-3); first term, 2025-26. Critical reviews and discussion of classic investigations and current research in paleoecology, evolution, and biogeochemistry.
Instructor: Tejada

Ge/Bi/ESE/CE 249. Stable Isotopes: Ecological and Environmental Applications. 9 units (3-3-3); first term, 2025-26. An introduction to various stable isotopes systems and their extensive applications in ecological, evolutionary, and environmental research. Topics covered include uses of stable isotopes in plant and animal ecology, hydrological systems, reconstruction of past climates, cultural development, and forensics. The class includes lectures and occasional lab sessions.
Instructor: Tejada

Ge 121 abc. Advanced Field Geology. 12 units (0-9-3); first, second, third terms, 2024-25. Prerequisites: Ge 120 or equivalent, or instructor's permission. For Ge 121a (Lamb): Ge 125 or instructor approval. Field mapping and supporting laboratory studies in topical problems related to the geology of the southwestern United States. Course provides a breadth of experience in igneous, metamorphic, or sedimentary rocks or geomorphology. Multiple terms of 121 may be taken more than once for credit if taught by different instructors.
Instructors: Avouac (a), Bucholz (b), Tejada (c)

Ge/Bi/ESE/CE 249. Stable Isotopes: Ecological and Environmental Applications. 9 units (3-3-3); first term, 2024-25. An introduction to various stable isotopes systems and their extensive applications in ecological, evolutionary, and environmental research. Topics covered include uses of stable isotopes in plant and animal ecology, hydrological systems, reconstruction of past climates, cultural development, and forensics. The class includes lectures and occasional lab sessions.
Instructor: Tejada

Ge/Bi/BE/CNS/ESE 147. Challenges and Opportunities in Quantitative Ecology. 6 units (6-0-0); third term, 2023-24. Ecosystems are defined by dynamical interactions between groups of organisms, the communities they constitute, and the physical and chemical conditions and processes occurring in the environment. These dynamics are complex and multiscale across both length and time. This course will explore quantitative approaches that observe, measure, model, and monitor ecosystems and the services that they provide society-and the emerging opportunities that could employ these approaches to improve and strengthen global sustainability when it comes to our own ecology. This course will feature lectures each week from different members of the Caltech faculty working on ecological problems from different angles in order to illustrate how fresh insights can emerge by drawing on diverse ways-of-knowing. Given in alternate years; not offered 2022-23.
Instructors: Fischer, Tejada