alt Hacker NewsThere are a couple of species that remain essentially unchanged for the last couple million years. Why can't humans become one of them?
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jl6 • today at 6:50 AM
Good question, with a couple of possible answers:
1) maybe those species aren’t as unchanged as we think, because our evidence of the past is limited to things like skeletons, and maybe the skeletal structure of the shark didn’t change much, but other aspects did.
But more likely…
2) maybe unchanging requires a stable environment with stable selection pressures - but humans have had a rollercoaster of change in selection pressures, possibly more than any other species.
Nothing stops mutating. What you see with those species is that they found a zone of stability in the fitness landscape, a local optimum. They still have mutants, you just don't see them outcompeting and shifting the makeup of the overall population as the dominant form is already the most fit.
Now consider our own species and the pressures that got us to this present body plan. They just aren't there. The shark still is facing pressures that favor the hundreds of millions of years old shark morphology. Are we facing pressures that our hominid ancestors faced? Doubtful. Look at how our bodies often react when they meet the pressures of our modern society: we often become anxious, depressed, and obese. Most of our ill behaviors such as this have some survival advantage to it that just isn't getting pressured in modern society. Your constant anxiety keeping you up at night is actually saving your family clan from a lurking predator in the bush. Your lack of portion control abilities means you can eat all the fish you just caught and pack on more fat to your frame to smooth over leaner times. Today these selective advantages are seen as illnesses people see doctors to get pills for. Our bodies are so misplaced for the society we've built for ourselves. Our mind's can't even fully fit this society into a working model ourselves without missing a lot of important information. We've out ran our capabilities a long time ago in some senses with the cultural/technological evolution that overshot our own biology. We are tumbling into some new body plan I'm not sure what exactly, but things aren't in any way stable now.