The study of human cranial morphology has a long and contentious history. This study is the first large scale analysis of ecoregion specific human cranial modularity and integration. It utilizes an analysis of morphometric craniofacial variation and ecoregion affinity to better understand the environmental contribution to biological shape. This study tested three hypotheses. First, that there was variation in craniofacial shape that was linked to an individual’s ecoregion. Second, that there were ecoregion specific patterns of cranial modularity. And third, that the patterns of cranial integration (or the level of covariation between any two modules) were also associated with an individual’s ecoregion, and that different environments would result in different patterns of modular dependence and independence. Three-dimensional scans of 298 human crania were collected from museums, representing four higher level ecoregions and 11 lower-level ecoregions. Each cranium was mapped and placed within two hierarchical ecoregions. By examining ecoregions, instead of individual climatic variables, this analysis gives a more complete picture of how the environment is influencing cranial variation. Modules, or relatively independent morphological regions of the crania, were identified and their level of integration was assessed for every ecoregion. Modular integration is an analysis of the relative strength of the covariation between any two modules, and previous research theorized that changes in integration reflected changes in modular independence during development (Bastir and Rosas, 2005; Hall, 2005; Raff, 1996). The variation in strength between modules, both intrapopulation and interpopulation, were assessed and various explanations were explored. This analysis found that each ecoregion exhibited significantly different craniofacial shape from one another. Patterns of integration were also variable by ecoregion, suggesting that the ecological shape variation observed was solidified early in development. This study also identified the presence of a nasal module in each ecoregion. Overall, the findings of this study demonstrate that human crania are variable by ecoregion and that environmental conditions have led to ecoregion specific patterns of cranial modular integration. / Anthropology
| Identifer | oai:union.ndltd.org:TEMPLE/oai:scholarshare.temple.edu:20.500.12613/7219 |
| Date | January 2021 |
| Creators | Kirkland, Scott, 0000-0003-2172-4342 |
| Contributors | Rockwell, Christie, Weitz, Charles A., Henry, Kevin A., Nelson, Frank |
| Publisher | Temple University. Libraries |
| Source Sets | Temple University |
| Language | English |
| Detected Language | English |
| Type | Thesis/Dissertation, Text |
| Format | 166 pages |
| Rights | IN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available., http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | http://dx.doi.org/10.34944/dspace/7198, Theses and Dissertations |
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