Doctoral Dissertation Research: Functional signals of upper limb use in the collarbone

人类进化史上具有决定性意义的里程碑之一是向用两条腿走路的过渡--两足行走--尽管很难重建化石物种在多大程度上同时在树上仍然活跃。本博士论文研究项目分析了不同活动方式的几个物种锁骨中不同类型骨骼的分布，以更好地重建和了解上肢在人类化石亲属中的用途。转向以两足动物为主的运动模式与人类历史上的其他几个关键发展相关联，包括石器的生产和使用、远距离狩猎以及相关的肉类准备和消费。在方法上仍然存在差距，并阻碍改进确定在人类进化中不再使用上肢进行运动的方法；这项研究的结果有助于以更高的分辨率重建人类进化过程中的运动模式。该项目为缺乏服务的学生提供与STEM教育和临床实践相关的培训。该项目量化了灵长类锁骨形态的不同方面，其结果有助于长期存在的关于早期古人类使用上肢的关键辩论。这项研究量化和比较了锁骨外部形状的变化，以及皮质和松质骨在灵长类锁骨中的分布，贯穿个体发育和不同运动适应的不同群体。它进一步模拟了形态变化如何影响运动过程中锁骨的负荷，并最终将这些结果应用于构建环境，以记录和解释早期原始人化石记录中的变化，以评估运动适应。这项研究进一步提高了生物人类学和相关领域的研究人员收集有关化石人类树栖行为程度的信息的能力，最终使人们能够更清楚地了解解剖学和生态学之间的联系。这一奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

One of the defining milestones in human evolutionary history is the transition to walking on two legs – bipedalism – although it is difficult to reconstruct the degree to which fossil species might have simultaneously still been active in the trees. This doctoral dissertation research project analyzes the distribution of different types of bone in the collarbone of several species who get around in different ways, to better reconstruct and understand the use of upper limbs in fossil human relatives. Shifting to a predominantly bipedal mode of locomotion is associated with several other key developments in human history, including stone tool production and use, long range hunting and associated meat preparation and consumption. Gaps have remained in approaches and have impeded the refinement of ways to identify the transition away from use of upper limbs in locomotion in human evolution; the results of this research contribute to the reconstruction of patterns of locomotion during human evolution with greater resolution. This project provides training relevant to both STEM education and clinical practice for underserved students.This project quantifies different aspects of the morphology of the primate clavicle, and the results contribute to longstanding key debates regarding upper limb use in early hominins. This study quantifies and compares variation in external clavicular shape, and the distribution of cortical and trabecular bone in the primate clavicle, throughout ontogeny and across groups with diverse locomotor adaptation. It further models how morphological variation affects the loading of the clavicle during locomotion, and finally applies these results to building context to document and interpret variation the early hominin fossil record with respect to assessing locomotor adaptation. This study further enhances the ability of researchers in biological anthropology and related fields to glean information about the degree of arboreal behavior in fossil hominins, ultimately allowing a clearer understanding of the associations between anatomy and ecology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.