This network diagram shows the various processes involved in aging. It's not one linear process, but many interacting factors.
John D. Furber of Legendary Pharmaceuticals has put together a visual model of aging referred to as 'The 2007 Network of Biological Interactions in Human Aging' that shows the interactions between various subcellular, cellular, extracellular matrix and organ system. This is a great representation of aging as it demonstrates no root cause but rather a network of problem areas that are interlinked. The goal of systems biology would be to flush this out in great detail allowing one to zoom in down to the specific genomic and proteomic components of aging. Systems biology would also pursue such a model to have a functional runtime component to it such that variables could be tweaked and changes introduced to predict impact elsewhere in the various biological networks.