ABSTRACT
Cell death occurring as a normal part of physiology has been observed in every multicellular organism in which investigators have bothered to look. This raises the question of how it evolved, and what it evolved to do. This chapter will attempt to answer these questions, but the answers are incomplete, and are largely speculative. However, while they can’t explain all the observed cell death phenomena, they are consistent with most of it, and will hopefully encourage the experiments required to support or disprove them.
