Reacción a "Two changes in the human pelvis that were key to walking on two legs discovered"

For me, as a palaeontologist, it is very interesting that one of the first changes to occur in our evolutionary lineage, as the authors explain at the end of their discussion, was precisely the more lateral (parasagittal) reorientation and shorter length of the iliac bone. Chimpanzees are facultative bipeds, but not very efficient ones (they expend a lot of energy and cannot travel long distances). Small changes in the shape of the ilium simply allowed Ardipithecus ramidus (4.4 million years ago), proposed as one of our earliest ancestors, to stand upright somewhat more efficiently than chimpanzees, which could have been a major evolutionary advantage in terms of energy savings and freeing up the arms to, for example, carry more food and travel further.

Continuing with what was said in the press release, I find it interesting to know how these crucial modifications from an evolutionary point of view appear simply by modifying growth or development patterns — lengthening or shortening times or modifying ossification patterns at the cellular level — without the need for enormous mutations or drastic genetic changes. This type of process explains how, without major genetic revolutions, small changes can occur that gradually accumulate and can produce very significant evolutionary results over time.

The effective, efficient and obligatory bipedalism that characterises us is more than just a modification of the ilium, but the authors propose a scenario of gradual changes in three phases in which the new features become established. In short, Darwin would be delighted with this type of discovery, both at the fossil record level, for example, that of Ardipithecus, and those reflected in this work at the molecular level.