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

人类进化史上的一个里程碑是向两条腿行走的过渡——两足行走——尽管很难重建化石物种可能同时在树上活动的程度。本博士论文研究项目分析了几种以不同方式行走的物种锁骨中不同类型骨骼的分布，以更好地重建和理解化石人类近亲上肢的使用。向以两足为主的运动模式转变与人类历史上的其他几个关键发展有关，包括石器的生产和使用，远距离狩猎以及相关的肉类制备和消费。方法上的差距仍然存在，并且阻碍了识别人类进化中远离使用上肢运动的过渡的方法的改进；这项研究的结果有助于重建运动模式在人类进化过程中更大的分辨率。该项目为服务不足的学生提供与STEM教育和临床实践相关的培训。该项目量化了灵长类动物锁骨形态的不同方面，其结果有助于长期以来关于早期人类上肢使用的关键争论。本研究量化并比较了灵长类动物锁骨外形状的变化，以及锁骨皮质骨和锁骨小梁骨在个体发育过程中的分布，并在不同运动适应群体中进行了比较。它进一步模拟了运动过程中形态变化如何影响锁骨负荷，并最终将这些结果应用于构建背景，以记录和解释早期古人类化石记录的变化，以评估运动适应。本研究进一步提高了生物人类学及相关领域研究人员收集古人类化石树栖行为程度信息的能力，最终使解剖学与生态学之间的联系更加清晰。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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.