Neoteny, Manipulation and Bipedalism

This is the abstract from an unpublished manuscript I wrote quite a while back (2015). The full article can be downloaded from Academia.edu

https://www.academia.edu/31526740/Neoteny_Manipulation_and_Bipedalism

Abstract: Although there are many established hypotheses for bipedalism in hominins none satisfactorily explain the basis for this development but rather propose different explanations or motives for increasingly sustained periods of bipedal behavior. The proposition here differs by suggesting an ontogenetic basis for extended periods of bipedal locomotion. This theory parsimoniously explains the underlying reason for the establishment of bipedalism by placing this particular adaptation within the context of the neotenous developmental trajectory of hominins. It is proposed that neotenous development and the plasticity this process afforded provided the platform upon which adaptations of the forelimbs supported increasingly refined manipulation. Natural selection for the advantages of increased dexterity likely resulted in further retardation of the hominin lineage by tending toward favouring progressively more neotenous hands. In parallel, increasingly neotenous feet demanded more sustained periods of bipedalism which indirectly conferred further self-selective advantages by freeing the hands for longer periods of time. Morphological evolvability conferred by neoteny may underlie both the evolution of the human hand and the subsequent transition toward obligated bipedal locomotion. Ultimately it was adoption of a bipedal stance which supported the accelerated encephalization maintained over the course of several million years until the fairly recent “self-domestication” of our species rapidly reversed this trend.

Keywords: bipedalism; encephalization; ontogeny; manipulation; neoteny