Why do we age and how do biologically immortal organisms combat the aging process?
In: Biology
Part of it is hardwired into us, also metabolism plays a big part. If you’re processing a lot of calories all the time it’s like you’re running the factory at full or near full speed. Part of longevity is tampering the metabolism down with fasting.
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Our bodies break down like how cars break down. Aubrey de Grey explains it well here: https://m.youtube.com/watch?v=AvWtSUdOWVI
Long story short, telomeres. You’re body has a little counter on it’s cells that counts the number of divisions it’s had. Once that hard counter runs out, the cell stops splitting and just as quickly your vitality goes with it. Your body heals more slowly, breaks more easily, the ability to add muscle goes down, if your body was a car it would have just passed the manufacturer warranty date. If nothing else gets your first, eventually your body just won’t have the juice to keep itself going.
How to fight it is a totally different matter, biologically immortal creatures go about it one of two ways. The first is to trick their cells into thinking they’re newly reborn, basically towards the end of their life they metamorphisize back into a younger version, simple organisms tend to do this. This method isn’t really workable for humans, unless you want to be reborn a baby with no functional memory of your past life. Immortal, yes, but not how you want it.
The other way is to slow the whole process way way down, if your cells split once every second, make them split once every 10 seconds instead. Lobsters owe their longevity to this method, but again not really workable for humans. All this would do is make us take forever to age, which may at first seem good, but that wouldn’t jive with how our bodies work, we would work out and take 10 times longer to heal after, get cut and it will take months to heal. People would look and act like teenagers but would get weird cancers that only really happen from long exposure, but since our cells aren’t replacing themselves as quickly the same cell would be exposed for longer.
For better or worse, both natural and pre-natural death has proven to be the exact catalyst for change that life needed to evolve. If one organism never died, it would compete against it’s offspring for resources. If it never died, it couldn’t evolve and be much more vulnerable to the unexpected. I suspect if we ever do discover functional immortality it won’t be biological, but technological.
This is a complex question and I’m far from being an expert on the topic, but:
There’s several mechanism of aging. Our cells first of all cannot replicate forever, the ends of DNA have something called telomere, that shortens every time the cells divide. Once they are too short the cell is set to die. (Except for cancer cells. Cancer cells are basically immortal. If you provide for them, they can survive for a very long time, check out the HeLa cells.) Second, all our life, we are experiencing a lot of stress, like UV lights from the sun, or chemicals that harm the DNA, but such agents are also created inside the body, as a part of normal functioning. Harming the DNA can result in the death of the cell or it not dividing anymore, or losing its function. Proteins can also be impacted, and “abnormal” proteins can aggregate in cells, killing them, or imparing their function. Also, as another commenter mentioned, reducing calorie intake can expand the lifespan of several animals, including humans, but I unfortunately don’t understand the mechanism well enough to simply explain it. There’s also a number of other reasons for aging, like mitochondria creating reactive molecules, stem cells depleting and so on.
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