What is the biological cause of aging?

I wrote a Quora answer to this question. I like it so much that I am posting it here for you to read-

Aging is a survival advantage. Getting old was one of the strategies used by early life in order to defeat those who did not get old in the race of evolution!

Unbelievable, I know!

How can the strategy of getting old give survival advantage to an organism over its peer?

1. Some biologists think that aging benefits specie by checking over-population.
2. Others think that getting old is an altruistic feature which gives younger animals opportunity to reproduce.

I think that both these theories are wrong as far as humanity is concerned.

In human history, cannibalism has existed. Human murder each other, selfishly even today for small reasons like resources, space, prestige, sexual opportunity and self defense etc. How can we explain the existence of altruism along with cannibalism? How can a an organism get old as an act of altruism while at the same time murder its peer for resources?

Altruism and inter-specie violence cannot go hand in hand. Yes, there exist animals that are altruist. Human being is not. We are altruistic at the family level, but other than this, it is a dog-eats-dog world.

As far as giving younger animals chance to reproduce, older ones do not need to make themselves old for this. They will die all the same, due to accidents. The probability that a child will live at least 20 years is higher than the probability that it will live till at least 40 years. This explains everything. Chances are that the younger organism will live to see the older one die. So, no altruism required here as well.

So, if these theories are wrong, what is the right theory?

My theory is based upon Life History Theory. According to LHT-

1. Resources available to any organism are limited,
2. To sustain life, all organisms bear some life processes like Repair and maintenance of the body, Reproduction, Intellectual work, Maintaining body and muscular mass, learning survival skills etc. All these processes consume resources, and are hence costly to bear,
3. In order to fulfill certain life processes, resources must be directed towards them. Any resource directed towards any life process will have to be directed away from all the other life processes, hence creating a competition for resources among the life processes. So, an internal trade-off mechanism of resources between different life processes must exist.

Such trade off has been confirmed experimentally in many dietary restriction experiments.

Now, why do we get old?

My assertion: Because we trade-off our youth by compromising repair and maintenance of our body in order to gain some extra reproductive success!

Explanation: Our body has to bear continuous damages from radiation, chemicals, pathogens and physical injuries. According to a mainstream biological theory of aging, we get old because we are unable to repair and maintain these constantly occurring damages in our body with 100% efficiency.

Why is that?

Because even if we do not get old, we will die all the same. Accidents happen, and they happened more when the early man lived in jungle. Imagine getting eaten by animals, getting bitten by thousands of insects you have never seen and snakes, getting injured in foot and becoming easy prey etc. We are going to die. That is certain. So why should we invest our energy in repairing and maintaining our body, when the same energy can be directed towards sexuality to gain extra reproductive success! Why should we not compromise our repair and maintenance process from 100% to 90% efficiency, so that the 10% energy gain gives us more children and an obvious evolutionary benefit over our non-aging peers (morons)??? There is no need to maintain a system which will die all the same. A calculated rate of aging, depending upon the mortality rate of a non-aging specie will a better life strategy.

Think like a mathematician, like a game theorist. Do I not make sense?

My theory beautifully explains why we get old. I actually wrote a popular science book on this topic- Modern Biological Theory and Experiments on Celibacy: Brahmacharya under Microscope - Jatin Shankar - Amazon.com

The Idea behind the book is that if we restrain our sexuality, our repair and maintenance process can become 100%. Do you know what that means? We will not get old!!!