Doctoral Dissertation Research: The Evolution of Locomotor Specializations in the Context of Adaptive Plasticity

可塑性是指生物体的行为、解剖或生理变化，以应对环境条件，并可能导致新的特征和行为的进化。关于人类两足行走（用两条腿行走）——人类谱系最早的定义特征之一——起源的许多假设都涉及到一个可塑性阶段。本博士论文项目考察了可塑性在灵长类动物运动特殊化中的作用，通过将人类置于更广泛的灵长类动物环境中来推进对人类两足动物的认识。这项研究强调了两足动物进化的潜在早期阶段，这项研究的发现可以为未来对人类化石记录的解释提供信息。本研究支持对代表性不足的高中生和本科生进行STEM培训和指导。该项目有两个主要目标。第一个目的是通过研究15种灵长类动物的肢体运动能力来研究肢体骨骼的可塑性和进化性之间的关系。研究人员收集并分析了人类、类人猿和猴子不同程度的肢体骨骼的3D地标数据。对于第二个目标，采用机器人模拟方法来模拟运动技能的可塑性如何导致新行为的起源，以及影响适应性和灭绝风险。基于六种现代灵长类物种和四种古人类化石物种的机器人模型在一系列模拟环境中运行。这些模拟的算法将两种不同形式的机器人建模——进化和发育——联系起来，可以应用于灵长类动物的适应性可塑性的其他实例，并可供其他研究人员使用。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。

Plasticity refers to alterations to an organism’s behavior, anatomy, or physiology in response to environmental conditions and can lead to the evolution of novel features and behaviors. Many hypotheses regarding the origin of hominin bipedalism (walking on two legs), one of the earliest defining features of the human lineage, involve a phase of plasticity. This doctoral dissertation project examines the role of plasticity in primate locomotor specializations to advance knowledge about human bipedalism by placing humans within a broader primate context. This research highlights the potential early stages of the evolution of bipedalism, and findings from this research can inform future interpretations of the human fossil record. This research supports STEM training and mentorship of underrepresented high school and undergraduate students. The project has two main objectives. The first objective is to investigate the relationship between plasticity and evolvability of limb bones in reference to the locomotor repertoire of 15 primate species. The investigators collect and analyze 3D landmark data from limb bones across humans, apes, and monkeys with varying degrees of specialization. For the second objective, a robotic simulation approach is used to model how plasticity of locomotor repertoire can result in the origin of novel behaviors, as well as impact fitness and extinction risk. Robotic models based on six modern primate species and four hominin fossil species are run through a series of simulated environments. The algorithm for these simulations links two different forms of robotic modeling – evolutionary and developmental – which can be applied to other instances of adaptive plasticity in primates and made available for other researchers to use.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.