Why do humans age? After we hit 30 the chance of dying in any given year increases logarithmically, according to the Gompertz-Makeham law of mortality.
But not all creatures follow this law. Some display what is known as negligible senescence. Lobsters, for example, get larger and larger but never become senile. Neither do clams. Researchers recently found a 507 year old clam and it only died when they ran tests on it to determine its age. Redwood trees; bowhead whales; giant turtles; jellyfish; none of these animals ever die of old age.
So why did humans evolve this trait when other species did not? Natural selection by definition favors traits that facilitate reproduction, not longevity. The antagonistic pleiotropy hypothesis suggests genes coding for traits that bestow greater fecundity early in life will increase in frequency even if these same genes affect us negatively in old age.
One study suggests menopause evolved because the genes that cause it also accelerate ovulation in young adulthood, leading to more offspring.
So embrace aging. Yes, it’s kind of a downer that our bodies gradually fall apart. But we wouldn’t have ever evolved such incredible bodies without it. Would you rather be a lobster?