The evolution and diversification of Pleistocene Homo

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dc.contributor.advisorAckermann, Rebecca Rogersen_ZA
dc.contributor.authorSchroeder, Laurenen_ZA
dc.date.accessioned2016-02-03T14:24:33Z
dc.date.available2016-02-03T14:24:33Z
dc.date.issued2015en_ZA
dc.descriptionIncludes bibliographical referencesen_ZA
dc.description.abstractThe morphologically diverse and geographically expansive Pleistocene Homo fossil record continues to be a topic of debate. Recent fossil discoveries have highlighted the diversity, as well as the difficulty of identifying evolutionary relationships, within our lineage. Previous studies have focused on making distinctions between inter-and intra-specific variation, with relatively poor understanding of population structure or the evolutionary forces which have shaped the complex phenotypic diversity within our genus. The focus of this thesis is to expand our current understanding of the cranial and mandibular variation within Pleistocene Homo by assessing patterns of variation within our lineage, exploring the morphological link between newly discovered Homo (and Homo-like) fossil species and existing Homo taxa, investigating the evolutionary processes acting during the emergence and diversification of our genus, and considering the possible ancestor-descendant relationships at the transition from australopith to Homo. Analyses are performed on three-dimensional scan data (landmarks and interlandmark distances) collected from specimens of Pleistocene Homo. To provide context, robust and gracile australopiths are incorporated due to their temporal and/or spatial correspondence. The core of this thesis consists of four manuscripts. A suite of quantitative methods are utilized in these manuscripts to evaluate the morphological diversity within this hypodigm. These include statistical tests developed from quantitative evolutionary theory, Mahalanobis' distances, Generalised Procrustes Analysis, and Euclidean Distance Matrix Analysis. The results of these analyses emphasise the importance of neutral evolutionary forces in shaping morphological diversity during the evolution of Homo. However, they also indicate that adaptive evolution /selection contributed to the differences in masticatory morphology within our genus, played a significant role in the dispersal of Homo out of Africa, and may have been an important driver of diversification during the transition from Australopithecus to Homo, as well as between Homo rudolfensis and other Homo groups. Importantly, they show that specimen affiliations, the effect of selection, as well as patterns of variability vary depending on the skeletal region analysed and extant model choice. Finally, they highlight the large amount of morphological variability during the emergence and evolution of our genus, supporting the coexistence of a diversity of forms, and the presence of multiple lineages. Taken together, these results reveal a complex evolutionary scenario shaping the diversity within Pleistocene Homo and their possible ancestors, challenging previous notions of a linear evolutionary trajectory. This conclusion emphasises the need for future research on hominin diversity to incorporate evolutionary process into models of evolutionary change.en_ZA
dc.identifier.apacitationSchroeder, L. (2015). <i>The evolution and diversification of Pleistocene Homo</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Archaeology. Retrieved from http://hdl.handle.net/11427/16715en_ZA
dc.identifier.chicagocitationSchroeder, Lauren. <i>"The evolution and diversification of Pleistocene Homo."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Archaeology, 2015. http://hdl.handle.net/11427/16715en_ZA
dc.identifier.citationSchroeder, L. 2015. The evolution and diversification of Pleistocene Homo. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Schroeder, Lauren AB - The morphologically diverse and geographically expansive Pleistocene Homo fossil record continues to be a topic of debate. Recent fossil discoveries have highlighted the diversity, as well as the difficulty of identifying evolutionary relationships, within our lineage. Previous studies have focused on making distinctions between inter-and intra-specific variation, with relatively poor understanding of population structure or the evolutionary forces which have shaped the complex phenotypic diversity within our genus. The focus of this thesis is to expand our current understanding of the cranial and mandibular variation within Pleistocene Homo by assessing patterns of variation within our lineage, exploring the morphological link between newly discovered Homo (and Homo-like) fossil species and existing Homo taxa, investigating the evolutionary processes acting during the emergence and diversification of our genus, and considering the possible ancestor-descendant relationships at the transition from australopith to Homo. Analyses are performed on three-dimensional scan data (landmarks and interlandmark distances) collected from specimens of Pleistocene Homo. To provide context, robust and gracile australopiths are incorporated due to their temporal and/or spatial correspondence. The core of this thesis consists of four manuscripts. A suite of quantitative methods are utilized in these manuscripts to evaluate the morphological diversity within this hypodigm. These include statistical tests developed from quantitative evolutionary theory, Mahalanobis' distances, Generalised Procrustes Analysis, and Euclidean Distance Matrix Analysis. The results of these analyses emphasise the importance of neutral evolutionary forces in shaping morphological diversity during the evolution of Homo. However, they also indicate that adaptive evolution /selection contributed to the differences in masticatory morphology within our genus, played a significant role in the dispersal of Homo out of Africa, and may have been an important driver of diversification during the transition from Australopithecus to Homo, as well as between Homo rudolfensis and other Homo groups. Importantly, they show that specimen affiliations, the effect of selection, as well as patterns of variability vary depending on the skeletal region analysed and extant model choice. Finally, they highlight the large amount of morphological variability during the emergence and evolution of our genus, supporting the coexistence of a diversity of forms, and the presence of multiple lineages. Taken together, these results reveal a complex evolutionary scenario shaping the diversity within Pleistocene Homo and their possible ancestors, challenging previous notions of a linear evolutionary trajectory. This conclusion emphasises the need for future research on hominin diversity to incorporate evolutionary process into models of evolutionary change. DA - 2015 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - The evolution and diversification of Pleistocene Homo TI - The evolution and diversification of Pleistocene Homo UR - http://hdl.handle.net/11427/16715 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/16715
dc.identifier.vancouvercitationSchroeder L. The evolution and diversification of Pleistocene Homo. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Archaeology, 2015 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/16715en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Archaeologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherArchaeologyen_ZA
dc.titleThe evolution and diversification of Pleistocene Homoen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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