Evolutionarily, these would be cases of antagonistic pleiotropy (39), a well-established concept in the evolutionary theory of aging.
This concept was developed as the mitochondrial theory of aging since mitochondria are the major producers of ROS in the cell [ 1].
In addition to theories of aging based on molecules and cells, there also exists a "psychosociological" theory of aging.
The "free radical theory" of aging was proposed by Denham Harman in the fifties and is based on the concept that normal aging occurs as the result of tissue damages inflicted by reactive oxygen species (ROS) [ 5].
The Harman free radical/oxidative stress theory of aging underpins one of the most popular concepts regarding the biochemical/molecular factors in aging [1].
The psychosociological theory of aging can be divided roughly into four component theories: disengagement, activity, life-course, and continuity theories.
Antagonistic pleiotropy (AP), or genetic tradeoff, is an important concept that is frequently invoked in theories of aging, cancer, genetic disease, and other common phenomena.
Certainly, mitochondria are indirectly featured in past theories of aging and directly in current aging theory.
Mechanisms of aging and longevity were selected based on major theories of aging, such as the theory of mutation accumulation, the theory of programmed cell death, etc. [ 4 ].
The description of theories of aging covers biological theories (including stress theories), psychological theories (including theories of cognition, theories of everyday competence, and social psychological theories), and sociological theories (including anthropological theories, life course theories, and social theories of aging).
Therefore, they serve as the ideal level for the development of student of understanding of both concept and theory.
