Evidence for evolution: human kidney development

[Vivre]

Hello,
I'd like to share an illustrative outline with you, showing and describing the in utero developement of the human kidneys where three different forms are built up from which the latest is kept to be used.


Taken from: Evidence for evolution: development of our kidneys by whyevolutionistrue 08.02.2012

... our own development does not successively resemble that of an adult fish, amphibian, and reptile before arriving at our own mammalian characteristics, but we do show developmental features resembling those of young ancestors. ... in some cases the order in which developmental features appear often corresponds to the order in which the ancestors with those features evolved.

One example is the development of the human kidney, which is pretty much the same as the development of any mammalian kidney. It turns out that, in utero, we develop three separate kidneys in succession, absorbing the first two before we wind up with the embryonic kidney that will become our adult kidney. The first two of these reprise embryonic kidneys of ancestral forms, and in the proper evolutionary order.

Pronephric kidney (0-12 secs into video) (filters wastes from coelom (body cavity) / excretes to the outside, no function in human / other mammalian embryos)
Mesonephric kidney (14-40 seconds) (filters wastes from blood / excretes to the outside of body via pair of tubes, functions for a few weeks)
Metanephric kidney (42 secs until end) (filters wastes from blood / excretes to the outside via pair of new tubes (ureters), it's the final adult kidney of reptiles, birds, mammals)