25.11.2021

The role of punctuated equilibrium and stabilizing selection on the evolution of Homo cranial morphology

Colloquium by Dr. Mark Hubbe

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Time: 25th November, 16:00

Speaker: Dr. Mark Hubbe

Title: The role of punctuated equilibrium and stabilizing selection on the evolution of Homo cranial morphology

Abstract:
The fossil record of the genus Homo shows a great diversity of cranial shapes and sizes, which is a direct result of the complex evolution of our lineage. The evolution of cranial morphology must strike a balance between maintaining the functionality of the several anatomical and developmental modules that define the skull and the external environmental pressures acting on individuals’ fitness over time. As such, the myriad of intrinsic and extrinsic evolutionary forces acting on cranial morphology can result in several different evolutionary processes, which ultimately produced the speciation events that defined our lineage. Despite the complex nature of the evolution of cranial morphology, few studies have explored the possible evolutionary pathways that led to the diversity of shapes seen in the genus Homo, especially when it comes to the role of stabilizing selection and non-linear evolutionary forces like punctuated equilibrium. In this talk, I will discuss the initial results of my work with Prof. Harvati during my recent visit to the DFG Center “Words, Bones, Genes, Tools”. Using data on over 50 fossil specimens of Homo as well as modern humans, we evaluated the likelihood of different evolutionary models to explain the morphological changes observed in our genus, through the incorporation of methods developed for paleontological series. For most of the anatomical regions of the skull, our analyses show much stronger support for evolutionary models that explain their differentiation as a product of stabilizing selection and quick periods of differentiation (Punctuated Equilibrium). With these results in hand, I will discuss the necessity of understanding better the developmental, functional, and evolutionary constrains that shape the evolution of the human head.

We welcome you all to join us on Zoom. The link will be sent around via email before the talk.