EAR-PF: Predator-driven evolution of shell structure at different scales during the Mesozoic Marine Revolution: An interdisciplinary experimental investigation

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。世界海洋生态系统目前正受到人类活动的许多压力。例如，全球变暖已经改变了海洋化学，影响了许多软体动物外壳的强度。这些贝壳是蛤蜊和蜗牛等生物生存的关键，它们利用贝壳作为防御机制，抵御鱼类和螃蟹等破坏贝壳的掠食者。除气候变化外，海洋生态系统还受到过度捕捞的压力，优先清除捕食者对其猎物产生级联效应。预测气候变化和不断变化的海洋掠夺制度的长期影响的一种方法是研究过去的类似事件。在中生代（2.5亿至6500万年前），世界经历了极端温暖的温室环境。此外，破壳掠食者变得越来越强大，对猎物施加了更大的选择压力。这项研究将使用物理和数值实验来分析温度升高和捕食压力的变化如何影响中生代海洋蜗牛的外壳，为现代生态系统保护工作提供信息。此外，通过研究蜗牛壳的特殊强度，本研究将应用于抗裂材料的仿生设计。在这项研究中使用物理模型还可以创建可访问的交互式3D打印博物馆展示，适用于包括古生物学，保护和生物力学在内的跨学科教育模块。约翰逊博士将指导那些对生物学、生态学、古生物学、生物力学或相关STEM领域感兴趣的高中和本科生。防御性蜗牛壳形态的变化是中生代海洋革命假说的核心--在温室条件下捕食者驱动的进化事件。然而，我们缺乏严格的定量指标来评估这段时间里捕食者驱动的进化。该项目将使用一种创新的方法来量化猎物的反应，通过实验确定腹足动物的外壳将如何在主要由外壳破碎捕食者驱动的模型系统中进化。这将使用一种新的跨尺度方法来完成，应用有限元分析建模，结合壳体宏观结构（形状）和微观结构材料特性，并验证现代和化石壳体的分析。这项研究将产生一个理论形态空间，它量化了一系列外壳形状和微结构组合的防御能力。从这项研究中产生的模型框架将有捕食者-猎物驱动的进化，保护古生物学和材料科学的研究的基础应用。世界海洋目前正面临着过度捕捞和气候迅速变化带来的巨大人为压力，这很可能对软体动物和鱼类产生不利影响。这项研究将为超越现代生态研究时间尺度的保护工作提供信息。此外，这项研究的结果将对开发更强、抗裂的仿生材料产生影响。该奖项反映了NSF的法定使命，并被认为值得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来支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). The world’s marine ecosystems are currently experiencing many pressures from human activities. For example, warming global temperatures have changed ocean chemistry in ways that influence the strength of many mollusk shells. These shells are key to the survival of organisms like clams and snails, which use their shells as a defense mechanism against shell-crushing predators like fishes and crabs. In addition to climate change, marine ecosystems have been stressed by overfishing, where the preferential removal of predators has cascading effects on their prey. One way to anticipate the long-term impacts of climate change and changing marine predatory regimes is to study similar events from the past. During the Mesozoic (250-65 million years ago) the world was experiencing extremely warm, greenhouse conditions. Additionally, shell-crushing predators became increasingly powerful, putting increased selective pressures on their prey. This study will use physical and numerical experiments to analyze how increasing temperatures and changes in predation pressures impacted the shells of marine snails during the Mesozoic to inform modern ecosystem conservation efforts. Moreover, by studying the exceptional strength of snail shells, this research will have applications for the bio-inspired design of crack resistant materials. The use of physical models for this research will also enable the creation of accessible, interactive 3D printed museum displays applicable to educational modules across disciplines including paleontology, conservation, and biomechanics. While conducting this interdisciplinary research, Dr. Johnson will mentor underrepresented and underserved students from high school and undergraduate programs, who are interested in biology, ecology, paleontology, biomechanics, or related STEM fields.Changes in defensive snail shell morphologies are central to the Mesozoic Marine Revolution hypothesis—an event of predator-driven evolution during a period of greenhouse conditions. However, we lack rigorous quantitative metrics by which to evaluate predator-driven evolution throughout this time. This project will use an innovative approach to quantify prey response by experimentally determining how gastropod shells would evolve in a model system driven primarily by shell-crushing predators. This will be accomplished using a novel cross-scale approach, applying finite element analysis modeling incorporating both shell macrostructure (shape) and microstructural material properties, and validating the analysis with modern and fossil shells. This research will generate a theoretical morphospace which quantifies the defensive capabilities of a range of shell shapes and microstructural combinations. The model framework generated from this research will have fundamental applications for studies of predator-prey driven evolution, conservation paleobiology, and materials science. The world’s oceans are currently facing intense anthropogenic pressures from overfishing and a rapidly changing climate, which are highly likely to negatively impact mollusks and fishes. This study will inform conservation efforts which extend beyond the temporal scale of modern ecological studies. Furthermore, the results of this study will have implications for the development of stronger, crack resistant bioinspired materials.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.