Well, we come right back to my question: Can you show me one observed example of how evolution has worked, say, in the development of a human being from an ape? That should be fairly simple, because that is a principal teaching of how evolution works for humans.
Sure. Humans evolved from Australopithecines, or their close relatives. Below the neck they are almost identical to us, but slightly transitional between us and forest apes.
Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins
Elaine E. Kozma, Nicole M. Webb, William E. H. Harcourt-Smith, David A. Raichlen, View ORCID ProfileKristiaan D'Août, View ORCID ProfileMary H. Brown, Emma M. Finestone, Stephen R. Ross, Peter Aerts, and Herman Pontzer
PNAS April 17, 2018 115 (16) 4134-4139; first published April 2, 2018
The biomechanical issues for bipedalism were largely resolved long before there were humans.

One problem was the lack of stability. Chimps and other apes can walk bipedally, but clumsily with an inefficient rocking gait. A broader pelvis was one adaptation, (which incidentally allows the birth of larger-brained offspring) but also the legs changed. The femur is bent inward, giving Australopithecines and humans a slightly knock-kneed posture, allowing efficient walking.

Notice also that the feet are adapted to walking, with the Australopithecines again transtitional between forest apes and humans, but more humanlike than apelike. They were still slightly adapted for climbing, though.
So evolution of humans from other apes was mostly above the neck. How did that happen?
Well, as you see, wider hips made it possible for infants to be born with larger brains. And in humans, the brain continues to grow,and the skull sutures remain open for a much longer time than in apes.
And that's the real point. We are examples of paedomorphosis; retention of juvenile characteristics. Very young apes have flat faces, small jaws, relatively large brains, and the foramen magnum (where the spinal cord enters the skull is positioned under the skull, not at the rear of the skull as it is in adult apes.
D'Arcy Thompson over 100 years ago, showed how this worked developmentally:

Top figures are ape and human infants. Bottom are adults. Notice how much the ape changes, and how little the human does. Neotony is largely the cause of human evolution. There is some hint of this process in Australopithcines and their kin, but not anything to the degree we see it in humans. Human evolution is essentially the evolution of our skulls; almost everything else was evolved before humans.
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