My favorite example of a vestigial/accidental/no-perfect-designer-would-have-done-it-like-this structure:
![[Image: Route_of_vas_deferens_en.svg]](https://upload.wikimedia.org/wikipedia/commons/0/01/Route_of_vas_deferens_en.svg)
The ancestors of humans had internal testicles that gradually descended. One of them got hooked over the path from the kidney to the bladder, resulting in a silly, asymmetrical, circuitous route.
Something similar happened with giraffes' facial nerves and their hearts (really, it happens for all mammals, but giraffes are the best illustration):
![[Image: GiraffaRecurrEn.svg]](https://upload.wikimedia.org/wikipedia/commons/7/7e/GiraffaRecurrEn.svg)
The nerve from the brain to the front part of the throat is a few inches long. The nerve from the brain to the back part of the throat - which is only a few inches from the brain - is thirteen feet in length, because it got hooked around the aorta way back in some protomammal.
(Both images from Wikipedia Article on Evidence of Common Descent)
The ancestors of humans had internal testicles that gradually descended. One of them got hooked over the path from the kidney to the bladder, resulting in a silly, asymmetrical, circuitous route.
Something similar happened with giraffes' facial nerves and their hearts (really, it happens for all mammals, but giraffes are the best illustration):
The nerve from the brain to the front part of the throat is a few inches long. The nerve from the brain to the back part of the throat - which is only a few inches from the brain - is thirteen feet in length, because it got hooked around the aorta way back in some protomammal.
(Both images from Wikipedia Article on Evidence of Common Descent)
How will we know, when the morning comes, we are still human? - 2D
Don't worry, my friend. If this be the end, then so shall it be.
Don't worry, my friend. If this be the end, then so shall it be.
