PATTERN, PATRON, PROCESS

This book is about the great mystery of how living organisms develop the shapes and proper relative positions both of the whole organism and of all the parts that make it up. These are large-scale structures, ranging from parts of a cell visible by optical microscopy up to gross anatomy. My primary interest is not in the structures themselves, most of which remain after life has departed and are indeed commonly described from studies of dead material. Nor is my attention given mainly to structural details on the molecular scale within the provinces of the biochemist and molecular geneticist, details that could be regarded as the ultimate limits of anatomy, cutting-up that has reached the atomic scale. I am concerned mainly with how the tiny, partly fragmentary and partly one-dimensionally ordered genetic beginnings are transformed into the three-dimensional organism by the processes of development. This book is about processes, as they occur during life and make up a large part of what distinguishes living from inanimate matter.

The proper study and description of processes may involve diverse branches of the physical and chemical sciences (Harrison 1993, Chap. 8), but must quite often be primarily based on dynamics. That is the kind of explanation of developmental events to which I have devoted most of my effort, and is the main topic of this book.