Description

Bioscience is the branch of natural science dealing with the structure and behaviours of the living organism known variously as 'Natural History', Natural Philosophy, and Natural Theology. Aging has long since been ascribed to the gradual accumulation of DNA mutations in the genome of somatic cells. However, it is only recently that the necessary sophisticated technology has been developed to begin testing this theory and its consequences. It is increasingly important for physicians who treat older persons, and for researchers on aging, to understand how molecular biology informs clinical expressions of aging and age-related conditions such as osteoporosis, diabetes, osteoarthritis, frailty, cancer, and dementia. Age is the main risk factor for the prevalent diseases of developed countries: cancer, cardiovascular disease and neurodegeneration. The aging process is deleterious for fitness, but can nonetheless evolve as a consequence of the declining force of natural selection at later ages, attributable to extrinsic hazards to survival: aging can then occur as a side-effect of accumulation of mutations that lower fitness at later ages, or of natural selection in favour of mutations that increase fitness of the young but at the cost of a higher subsequent rate of aging. The book concludes that the complex relationship between population aging and longevity is not written in stone, and can be modified by properly designed choices.