Testing Adaptive Hypotheses of Plio-Pleistocene Hominin Craniofacial Evolution

该项目研究了已灭绝人族主要群体之间的进化差异，特别关注与饮食和认知相关的形态变化。这一结果将促进对进化过程的了解，揭示饮食驱动的自然选择如何与现有的形态整合模式相互作用，从而产生进化变化。该项目将支持一名女性研究员，并扩大科学基础设施。它还将为一名博士后研究员和一名来自代表性不足群体的本科生提供3D扫描、生物力学和进化建模方面的培训机会，从而扩大对科学的参与。研究人员将使用美国国家科学基金会支持的CREATE方法，根据该项目的结果制作一个本科教学模块。这项研究还将收集和存档许多3D表面模型和生物力学测量结果，供其他研究人员和学生使用。拟议中的研究将检验关于自然选择在人族进化中所起作用的假设，包括：1)加工坚硬食物的选择推动了人类早期祖先——南方古猿（australopiths）头骨的进化；2)复杂认知的选择导致了我们人类属（Homo）早期成员的大大脑（从而产生了神经颅骨）。研究人员将利用现有的定量遗传学测试，利用咀嚼生物力学和大脑大小的形态学数据来区分自然选择和中性进化过程。研究人员将测量从上新世到更新世三个主要类群的化石表面扫描产生的3D模型：类人猿、南方古猿和早期人属。此外，现存物种的测量结果将用于模拟性状变异和共变异的种群模式，作为灭绝物种的代理。性状变异和共变异的程度是影响种群对自然选择的反应能力的关键参数，也是种群因遗传漂变等随机过程而变化的方式的关键参数。该研究的创新方面包括使用生物力学信息变量来测试关于选择和评估测试对选择化石活体代理的敏感性的假设。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。

This project addresses the evolutionary divergence of major groups of extinct hominins from one another, with a particular focus on morphological changes associated with diet and cognition. The results will advance knowledge about evolutionary processes, shedding light on how diet-driven natural selection can interact with existing patterns of morphological integration to produce evolutionary change. The project will support a female Investigator and expand scientific infrastructure. It will also generate opportunities for training in 3D scanning, feeding biomechanics and evolutionary modeling for a postdoctoral researcher and an undergraduate student from an underrepresented group, thus broadening participation in science. The investigators will use the NSF-supported CREATE approach to produce an undergraduate teaching module using the results of this project. The research will also result in the collection and archiving of many 3D surface models and biomechanical measurements to be used by other researchers and students.The proposed research will test hypotheses about the role of natural selection in hominin evolution, including that: 1) selection for processing hard or tough foods drove skull evolution in australopiths, a group of early human ancestors, and 2) selection for complex cognition led to large brains (and thus neurocrania) in early members of our own genus, Homo. The researchers will take advantage of existing quantitative genetics tests that can distinguish between natural selection and neutral evolutionary processes using morphological data that are informative about chewing biomechanics and brain size. The researchers will measure 3D models generated from surface scans of fossils from three major groups of Plio-Pleistocene hominins: Paranthropus, Australopithecus and early Homo. In addition, measurements from extant species will be used to model population patterns of trait variation and covariation as proxies for the extinct species. The extent of trait variation and covariation are key parameters influencing the ability of a population to respond to natural selection, as well as the manner in which populations change due to random processes like genetic drift. Innovative aspects of the research include the use of biomechanically informative variables to test hypotheses about selection and assessment of how sensitive tests are to choice of living proxy for the fossils.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.