why do organic bodies degrade over time and not continually regenerate?
In: Biology
There are some relatively simple organisms, like earthworms, whose physiology is very strictly defined by their genes. So if they’re damaged severely to the point of being torn in half, as long as the remaining sections can stay alive, they can regrow. But they don’t have a brain and their nervous systems are very simple.
But even then, cells have a built-in limitation. The are sections of DNA at the ‘ends’ of all our chromosomes, called telomeres, that become shorter and shorter every time the chromosome duplicates. Eventually they wear off completely, and the chromosome starts to break apart and lose the informative sections. The result is that most cells are able to make only a limited number of copies of themselves before breaking down.
There are enzymes that are capable of rebuilding the telomeres. Our limited lifespans are a feature of our design, not merely an accidental deficiency; it’s our nature to wear out and die. It’s thought this is to give our offspring a better chance to survive in a world with limited resources.
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