25. From Cells to Organisms

This lecture introduces the second major section of our course, Development and Homeostasis, by setting up two major questions: First, how do single cells proliferate and form complex multicellular organisms with a diverse array of different cell types Second, how do different cell types in a complex multicellular organism coordinate their activities in such a way as to maintain the integrity and function of the organism as a whole The first question brings us to a discussion of developmental biology, while the second brings us to a discussion of homeostasis and the physiological mechanisms organisms use to protect and maintain an internal environment.