CHAPTER 1 INTRODUCTION: THEMES IN THE STUDY OF LIFE OUTLINE I. Life?s Hierarchical Order A. The living world is a hierarchy, with each level of biological structure building on the level below it B. Each level of biological structure has emergent properties C. Cells are an organism?s basic units of structure and function D. The continuity of life is based on heritable information in the form of DNA E. Structure and function are correlated at all levels of biological organization F. Organisms are open systems that interact continuously with their environments G. Regulatory mechanisms ensure a dynamic balance in living systems II. Evolution, Unity, and Diversity A. Diversity and unity are the dual faces of life on Earth B. Evolution is the core theme of biology