Evolution and humans: our feet are special (Evolution)

by David Turell @, Monday, October 08, 2018, 22:49 (1965 days ago) @ David Turell

They did not develop from chimp feet:


"in 1995, scientists proposed that the anatomy of the ankle joint and heel (the hindfoot) existed before the anatomy of the human forefoot as it pertains to bipedalism. This was based on the discovery of “Little Foot,” an almost complete Australopithecus fossil skeleton recovered from Sterkfontein, South Africa dating to 3.3 million years ago, which exhibited similar hindfoot traits. Scientists believed that the foot of Australopithecus was adapted for bipedalism but it also allowed this early human ancestor to take refuge in the trees if needed. In piecing together these discoveries, it became clear that the evolutionary story of the human foot wouldn’t be explained linearly. The human foot evolved independently of other developments within human evolution and at different rates between species.


"One of the things we can say with certainty is that the modern human foot did not evolve from the chimpanzee foot. As reasonable as it may seem to draw comparisons between the two, the clear divergence between the genera from a last common ancestor (LCA) means that hominins and panins evolved feet to suit their needs. A major difference between the two stems from flexibility. The former’s foot is adapted for a stiff push-off which is necessary for bipedal locomotion. The latter’s feet maintains greater flexibility overall and grasping abilities that enable climbing trees as well quadrupedalism on the ground.


"Following the transition from Australopithecus to Homo, toes decreased in length and curvature, the ankle and corresponding musculature reduced in size, and full foot arches emerged. The big toe shifted to align with the other toes rather than curving inward enabling a more efficient push-off for bipedalism. There are some exceptions to these developments. In Homo naledi, for example, the toes are more curved than they are in the Homo genus overall. And Homo floriensis has an elongated forefoot, which most closely resembles that of bonobos. These kinds of variations aren’t unusual; the heel bones of modern great apes vary between species. These cases illustrate a diversity in foot evolution and locomotion, which with time may offer greater contextual clues about the lives of these groups.

"The story of the human foot is still unfolding. It is unique because it is best suited to our style of bipedal locomotion. The variations that scientists have found in foot bones for australopiths suggest there was variation in how they walked even among themselves, which is true of humans today: we have different stride lengths and different ways of coming down on our feet. Some have a more forceful step than others, to say nothing of how the feet of dancers are changed with years of training."

Comment: There is no doubt in my mind humans were especially designed. we can add feet to the big brain and other differences.

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