Paläoanthropologie

Evolutionary Processes Driving Human Origins and Variation

One of the most important goals of the Paleoanthropology work group is the understanding of the evolutionary processes which critically influenced human evolution and which shaped modern human phenotypic variation around the globe today.

We approach this goal in an interdisciplinary and integrative fashion

Our comparative samples comprise a large number of modern human population series from across the modern human geographic and ecological range. They also include our closest living relatives, non-human primate species.

The proximal goals of this work are to disentangle the evolutionary mechanisms underlying human phenotypic variation and to apply these findings to the interpretation of the human fossil record.

Ultimately we aim to elucidate the biological and historical processes through which have shaped human evolution in the past (and are likely to do so in the future). Within our theoretical framework of comparative study we apply the methodologies:

Additionally, we integrate climatic (Harvati and Weaver, 2006a,b; Tzedakis et al. 2007; Hubbe et al. 2009; Noback et al. 2011, [see citations]), archaeological (Hubbe et al. 2011), stable isotopic (e.g. Richards et al., 2008) and genetic (Harvati and Weaver, 2006a,b) data with phenotypic data.


Several interconnected research projects on this wide ranging theme are being conducted or planned for the near future by the Paleoanthropology group:

The influence on climate and diet on human craniofacial morphology.

A link between climatic adaptation / dietary function on the one hand, and craniofacial morphology on the other has long been postulated in the interpretation of fossil as well as modern human skeletal variation. Our recent seminal studies confirmed the hypothesis of climate selection of human cranial anatomy, especially in the face. This work has been widely cited in the literature and featured in popular science reports (Science, Nature).

Since 2010 a dissertation by Marlijn Noback aims to further evaluate the influence of climate in combination with dietary functional requirements in shaping modern human external and internal cranial morphology. This project is conducted on CT scans of a large comparative sample of geographic populations of known distinct climatic categories and dietary adaptations, and has been awarded four external grants (SYNTHESYS Copenhagen and Vienna, L.S.B. Leakey Foundation and Wenner-Gren Foundation dissertation grants).

 

Ontogenetic and Phylogenetic Constraints.

Among the factors that limit variation and evolvability of craniofacial morphology are phylogenetic and ontogenetic constraints. However very little information is available on the variability of developmental trajectories across primate and hominin species.

The PhD dissertation completed in 2010 by Dr. Nandini Singh explored the covariation patterns and ontogenetic trajectories in the cranial morphology of great apes and humans, identifying commonalities and differences across species. An extension of this work is funded by a Marie Curie postdoctoral fellowship to Dr. Singh (Marie Curie Reintegration Grant ‘No two halves are the same: an analysis of cranial asymmetry in human and non-human apes’) explores the growth of pathological individuals to examine the influence of ill health on craniofacial variation.

 

The effects of Locomotion and Lifestyle on the Skeleton.

Because bone responds to habitual mechanical loads through remodeling, stress trajectories caused by common loads can be reconstructed from trabecular bone architecture. Locomotor patterns, activity levels and lifestyle have all been shown to have major effects on the skeleton. Changes in lifestyle and mode of subsistence, such as those brought about by the development of agriculture and sedentism, result in changes in the mechanical loading of the skeleton throughout development and have profound effects, both systemic and localized, on the skeleton.

Paleoanthropology postdoctoral fellow Dr. Heike Scherf explores the signatures of locomotor and activity patterns on the trabecular bone architecture, and the effects of lifestyle on the structure, strength and health of bone (Saparin et al., 2011).

Paleoanthropology / DAAD postdoctoral fellow Dr. Thomas Rein plans to extend this work to explore the manifestations of subsistence strategies on forelimb internal and external morphology across human populations and in fossil human species. Dr. Rein is the recipient of a University of Tübingen fellowship for young scientists (Nachwuchsförderung) scheduled to begin in June 2012.

 

Modern human dispersals and population diversity.

At a worldwide scale, modern human genetic and morphological intra-population diversity decreases as a function of geographical distance from Africa. This pattern is interpreted to signal the effect of ancient population demography and the out-of-Africa expansion. Under this assumption, competing modern human dispersal models can be tested. Using cranial morphometric data, we have tested models of dispersal into the Americas (Hubbe et al 2010 [article], Hubbe et al 2011 [article]). The dissertation by Hugo Reyes Centeno, completed in 2015, used genomic and cranial morphometric data to test current hypotheses of the modern human out-of-Africa process and dispersal into Eurasia (Reyes-Centeno et al 2014 [article], Reyes-Centeno et al 2015 [article]).