Atoms are bound into molecules, which are organized into cells, which are layered into living creatures. Life is a sequence of structures, each nested upon previous ones. Cells arise from  previous cells. Creatures emerge from previous creatures, which themselves emerged from previous creatures. Every being is embedded in the previous form.

Our parents, grandparents, and great-grandparents live on in us. Every being is part of this continuum, which leads back to the very origins of life. Yet every human being still begins as a single cell, a seed which contains the entire tree of life.