EAR-PF: Respiratory physiology and survivorship during the End-Permian Mass Extinction

Jason Pardo博士被授予美国国家科学基金会地球科学博士后奖学金，在Kenneth Angielczyk博士的指导下在菲尔德自然历史博物馆开展研究和教育活动。大约2.52亿年前，一场大灭绝事件杀死了地球上95%的生命，其中包括80%的陆生物种。究竟是什么导致了这次大灭绝还存在争议，但有可能是氧气水平的下降起了作用。一个可能的证据是，哺乳动物的祖先进化出了一种将鼻子和嘴分开的骨架，使它们能够同时咀嚼和呼吸。这名研究员将测试这种创新是否帮助哺乳动物的祖先在这次大灭绝中幸存下来。帕尔多将使用医学成像和计算机建模来测试将鼻子和嘴分开是否能使哺乳动物更有效地呼吸，以及这是否能解释为什么一些哺乳动物的祖先灭绝了，而另一些幸存了下来。作为这项奖学金的一部分，Pardo将通过菲尔德博物馆的一个项目制作教育材料，该项目支持芝加哥公立学校系统多样化的科学教育。这项研究将通过深入了解地球历史上最极端的大灭绝，以及如何测试不同程度的鼻子和嘴的分离（在一些遗传疾病中很常见）如何影响呼吸，从而促进科学的进步。二叠纪末大灭绝（EPME）是一个全球性的气候事件，被认为是造成95%的海洋物种和80%的陆地物种灭绝的原因，极大地和永久地重塑了这两个领域的生态系统。尽管导致陆生动物灭绝的确切杀死机制仍在争论中，但越来越清楚的是，二叠纪和三叠纪脊椎动物生理学的可量化代用物可以更精确地理解导致EPME的地质过程如何转化为陆生动物群落的灭绝和生存模式，特别是在哺乳动物（兽头类）的前身中。帕尔多将探索一个尚未被充分研究的生理系统——次级上颚的影响。次上颚是口腔和鼻腔通道之间的骨骼分离，形成一个专门的上呼吸道系统，在咀嚼、哺乳和吸热中起重要作用，每一个都与呼吸能力和功能有直接或间接的联系。Pardo将明确地描述该系统的进化，其生理相关性及其对整个EPME的治疗性疾病存活的影响之间的相互作用。帕尔多将通过三个主要目标来实现这一目标。Pardo将使用CT扫描来精确量化有和没有完整的次腭兽鼻道形状的变化。Pardo将使用计算和物理模型来测试鼻通道形状和次腭完整性的变化是否会产生与气流相关的生理参数的可测量差异。最后，Pardo将使用系统发育比较方法来测试这些可估计的呼吸生理学差异是否可以预测整个EPME的生存率。帕尔多将把这些结果与科学蜥蜴的相似结果进行比较，以证实帕尔多的结果在生物学上的适用性。科学蜥蜴是一种与兽头龙腭功能类似的现代动物。Pardo的结果将提供一个全面的框架，以评估哺乳动物先驱的呼吸创新，以及呼吸压力是陆地生态系统中EPME杀死机制的一个组成部分的可能性。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。

Dr. Jason Pardo has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and education activities at the Field Museum of Natural History under the mentorship of Dr. Kenneth Angielczyk. Approximately 252 million years ago, a mass extinction event killed 95% of all life on earth, including 80% of all terrestrial species. Exactly what caused this mass extinction is debated, but it is possible that a drop in oxygen levels played a role. One possible line of evidence for this is that the forerunners of mammals evolved a bony shelf that separates their nose from their mouth, allowing them to chew and breathe at the same time. The fellow will test whether this innovation helped the forerunners of mammals survive this mass extinction. Pardo will use medical imaging and computer modeling to test whether separating the nose from the mouth could have made mammals breathe more efficiently, and whether this could explain why some forerunners of mammals went extinct and why others survived. As part of this fellowship, Pardo will produce educational materials through a program at the Field Museum which supports science education in the diverse Chicago Public School system. This research will promote the progress of science by providing insight into the most extreme mass extinction in Earth’s history, as well as how testing how different levels of separation of the nose and mouth (common in some genetic diseases) affect breathing.The End-Permian Mass Extinction (EPME) was a global climatic event which is thought to be responsible for the extinction of 95% of marine species and 80% of terrestrial species, dramatically and permanently reshaping ecosystems in both realms. Although the precise kill mechanism responsible for the terrestrial extinction remains under debate, it is increasingly clear that quantifiable proxies of physiology in Permian and Triassic vertebrates can provide a more precise understanding into how the geological processes responsible for the EPME were translated into patterns of extinction and survival in terrestrial communities, particularly among the forerunners of mammals (therapsids). Pardo will explore the impact of an understudied physiological system, the secondary palate. The secondary palate is a bony separation between the mouth and nasal passages, forming a dedicated upper respiratory system which plays important roles in chewing, suckling, and endothermy, each with direct or indirect ties to respiratory capacity and function. Pardo will explicitly characterize the interplay between the evolution of this system, its physiological relevance, and its effects on therapsid survivorship across the EPME. Pardo will do this in three major aims. Pardo will use CT scanning to precisely quantify variation in the shape of the nasal passage in therapsids with and without a complete secondary palate. Pardo will then use computational and physical models to test whether variation in the shape of the nasal passage and completeness of the secondary palate produce measurable differences in physiological parameters associated with airflow. Finally, Pardo will use phylogenetic comparative methods to test whether these estimable differences in respiratory physiology can predict survivorship across the EPME. Pardo will compare these results with parallel results from scincid lizards, a modern analog of therapsid palate function, in order to confirm biological applicability of Pardo’s results. Pardo’s results will provide a comprehensive framework in which to assess respiratory innovation in the forerunners of mammals as well as the possibility that respiratory stress was a component of the EPME kill mechanism in terrestrial ecosystems.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.