Saturday, May 7, 2011

Planned Obsolescence Theory of Biological Aging

"Planned obsolescence" was a term used in the 1950s and 1960s to describe products designed to have a limited life span. Cars, for example, were supposedly built to last less than ten years so that a continuing stream of replacement cars would be needed in future years. Planned-obsolescence theories of aging suggest that the human body is built so that it will give out after its useful life is over, to be replaced by a newer model.

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While such an argument seems counterintuitive at first, it does have some grounding in evolutionary biology. Within a population, it is important that there be at least a small amount of turnover, with older members of the group dying and being replaced by newborns. While this borders on a group selectionist argument, it still has important implications. Firstly, it is important that new individuals are born into the population so that natural selection has something on which to operate. Without the mixing of genetic material that occurs with sexual reproduction, the gene pool stagnates and the population’s ability to adapt to new conditions is diminished. Secondly, turnover allows the population to maintain a more stable growth rate and a more evenly distributed demographic. For example, a population in which there is no loss of individuals due to old age increases the stress on the population, as the ever-increasing population must waste limited resources on post-reproductive individuals who are not contributing in any significant way to their off-spring’s reproductive success. This implies that aging plays a role in creating turnover within a population in order to promote genetic diversity and limit the rate of population growth.

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Planned Obsolescence Theory is considered one of the most popular and well-accepted by scientists Genetic Theories of Aging as it focuses upon the encoded programming within our DNA. Our DNA is the blue-print of individual life obtained from our parents. It means we are born with a unique code and a predetermined tendency to certain types of physical and mental functioning that regulate the rate at which we age.

No, we do not have the exact replica of the DNA of our parents.  Our parents only influence the genetic composition of our bodies. Each of us is born with unique genetic codes that can only be attributable to us. Our DNA regulates the mental and physical functions of our bodies. It also determines the rate at which we age. Based on this theory of aging, our DNA determines when we will become obsolete or old.

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But this type of genetic clock can be greatly influenced with regard to its rate of timing. For example, DNA is easily oxidized and this damage can be accumulated from diet, lifestyle, toxins, pollution, radiation and other outside influences.

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Thus, we each have the ability to accelerate DNA damage or slow it down.

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