For example our hands become wrinkly after getting wet so our ancestors could grip onto trees better after swimming.
Would we really go extinct as a species if we didn’t develop that extremely specific trait at one point?
Same for crying as an emotional response, or eyebrows keeping sweat out of our eyes, or goosebumps making our hair stand to be more intimidating to predators.
I understand why these would be helpful, but I don’t see why these were so necessary to the human race’s continuation that nearly every human has these traits.
In: 0
It’s not that a trait has to be a life-or-death decision (though obviously, in evolution, nothing is “deciding”). The trait just has to make it so that you leave behind more descendants than individuals that don’t have that trait.
An example of this is the fact that humans can’t make our own Vitamin C.
Vitamin C is an essential nutrient. Most mammals can make it themselves. We can’t – if we don’t have it in our diets, then we develop scurvy. So why can’t we make our own?
Well, millions of years ago our ancestors had a diet that was naturally rich in Vitamin C. By a freak mutation, one of our ancestors lost the ability to make their own Vitamin C. If we hadn’t had our diet, this would have been fatal, and they would have died and not passed it on.
But that’s not what happened. Since they were already getting Vitamin C through their diet, the loss of that functionality didn’t kill them. Instead, they were able to use the energy and resources that would have been spent synthesizing Vitamin C to do other things. Develop a bigger brain, make more of a different vitamin, whatever. The point is that thanks to that mutation, they had an advantage over other human ancestors. Their descendants retained that advantage, and eventually the trait spread to our entire species.
Latest Answers