The Evolution of Aging: How New Theories Will Change Medicine by Theodore Goldsmith

Author:Theodore Goldsmith
Language: eng
Format: epub
Tags: medicine, health, aging, biology, gerontology, aging theory, senescence
Publisher: Azinet Press

Octopus Suicide

The female octopus displays what appears to be a very explicit example of programmed death. The octopus, which normally only reproduces once stops feeding and dies shortly after reproducing. However, surgical removal of the optic glands prevents (Wodinsky, et al[23]) this result and the animal begins feeding again and survives for at least another breeding season. Apparently, the optical apparatus provides some hormonal signal to activate the programmed death mechanism.

Here we have a case of not only programmed death but actual programmed suicide or death resulting from a behavior. The animals die of starvation. They starve because they do not eat. They do not eat because they do not experience hunger. Hunger is controlled by hormones. Therefore, life span in this instance is controlled by a complex central mechanism.

This characteristic of the octopus has two very interesting attributes. First, unlike the salmon, there does not appear to be any obvious potential orthodox Darwinian (individual) benefit to descendants resulting from death of the parent. Second, life span control involves a behavior and suggests that other behaviors might be significant in regulating life span.

The octopus life span control mechanism involves communication with the central nervous system in both directions: Sense organs are involved in detecting the circumstances leading to activating the suicidal behavior, and, the execution of the behavior involves inhibiting the organism’s normal hunger response, a nervous system function. This is a textbook example of the sense/process/execution organization seen in non-genetic adaptation.

A traditional explanation for organisms that die after reproducing is that they die of “exhaustion” associated with reproduction. The idea is that they are the result of a tradeoff between more vigorous reproduction and a longer life, a tradeoff that is supported by traditional evolutionary mechanics. It seems obvious that this explanation cannot be applied to the octopus as the specimen successfully reproduces and then survives (even with surgery) if the suicide mechanism is inhibited.

Any discussion of animal suicide invariably results in someone mentioning lemmings. Some have observed lemmings apparently jumping off cliffs or into water. However, current scientific consensus is that lemmings do not commit suicide but rather die by accident (pushed off cliffs by other lemmings) or intentionally jump in a non-suicidal effort to cross an obstacle during mass migration.

Sex and Aging

There have long been reports that people having more sexual activity tend to live longer. (Some might suppose that this is related to the stress effect!)

In 1997, Smith, Frankel, and Yarnell published a paper in the British Medical Journal titled Sex and death: are they related?[24]. This 10-year study of 918 men from the area around Caerphilly, South Wales correlated “orgasmic frequency” with mortality. The study found that men (aged 45 – 59 at the start of the study) with a high (twice per week or more) frequency of orgasm had a mortality risk 50 percent lower than men reporting a low (less than monthly) frequency. Heart disease risk was especially beneficially affected.

Obviously a major issue here is determining whether sex causes good health or good health causes more sex.

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