Mammalian lactation as a framework for teaching development, physiology, and cell biology for social change.

Mammalian lactation is a dynamic process that develops throughout the lifespan of an organism. Here we present a framework for a third semester core course in biology that centers course content on lactation allowing examination of the developmental process as a dynamic whole-body experience involving changes occurring at the molecular, cellular, and organ levels of organization. Inequitable economic, socio- and geopolitical systems structure social determinants of health, affecting rates of breastfeeding in human populations. By integrating content exploring the ways social and biological systems impact breastfeeding rates in human populations, students develop abilities to understand the relationship between science and society throughout the course, a critical core competency for engaging in social change. Importantly, they interrogate social systems while simultaneously learning about many canonical biological processes including how natural selection and constraint have shaped the anatomy, physiology, cell biology, and biochemistry of lactation, how proteins, lipids, and carbohydrates are synthesized, processed, and exported through the endomembrane system in eukaryotes, and how neuronal and hormonal feedback mechanisms regulate milk synthesis and secretion. The course is structured using a flipped-classroom design emphasizing revision and student-self assessment that supports development of biological knowledge, social responsibility, and metacognitive skills. Because mammalian lactation includes fascinating, nuanced, and complex components that cross interdisciplinary boundaries, it provides a wealth of opportunities for faculty to teach developmental biology for social change.