networks begin to decline. Only thing remaining is the contacts for the most important social functions. Cognitive deterioration due to aging and loss of support systems leads to more declines in old age. Social groups- A decline in social groups mimics the declines associated with the aging process. Ecosystems forming a global ecological network- Networks within our ecosystems show us that we should be very concerned about the aging of our habitat. Elements of human systems- The aging process can be portrayed through human conceptual, cultural, and technological networks. With time, each of these networks begin to decline. See also • DNA damage theory of aging References Systems biology Theories of ageing Theories of biological ageing Proximate theories of biological ageing