Life and death: a biologist's view.

The strict link between life and death of an organism should be discussed and compared to the life cycles of molecules and cells that allow the organism's development and survival. Indeed, a brief consideration of the main features of biological functions reveals that they occur at widely different levels of organization, ranging from molecules to species and ecological systems, and occupying widely different spatio-temporal domains. Biological functions are characterized by the integrated motion of their constitutive parts, and operate in cyclic fashions that comprise on and off phases. The birth and death of molecules, cells, organisms or species represent a special class of cycling functions that support the life cycles of the entities that include them. Under this perspective, the life cycles of past, present and future human beings may be viewed as necessary support to the longer lasting and more widely spreading life cycles of families, nations, and civilizations. If due consideration is given to our deep mental nature, one may cherish the conclusion that past, present and future human beings may be all supporting the life cycle of a superior mental entity that includes us in the same way we include our own cellular and molecular components.