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

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。目前，世界海洋生态系统正面临着来自人类活动的诸多压力。例如，全球变暖已经改变了海洋化学成分，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，它们利用它们的壳作为防御机制，抵御鱼类和螃蟹等咬碎壳的捕食者。除了气候变化之外，过度捕捞也给海洋生态系统带来了压力，因为捕食者的优先清除对猎物产生了连锁反应。预测气候变化和不断变化的海洋捕食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 - 6500万年前），地球经历了极端温暖的温室环境。此外，粉碎壳的捕食者变得越来越强大，给猎物带来了更大的选择压力。本研究将使用物理和数值实验来分析中生代温度的升高和捕食压力的变化对海蜗牛壳的影响，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，这项研究将应用于抗裂材料的仿生设计。使用物理模型进行这项研究也将使创建可访问的，交互式3D打印博物馆显示适用于跨学科的教育模块，包括古生物学，保护和生物力学。在进行这项跨学科研究的同时，约翰逊博士将指导来自高中和本科课程的代表性不足和服务不足的学生，他们对生物学，生态学，古生物学，生物力学或相关STEM领域感兴趣。防御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内捕食者驱动的进化。该项目将采用一种创新的方法，通过实验确定腹足类贝壳在主要由粉碎壳的捕食者驱动的模型系统中如何进化，来量化猎物的反应。这将使用一种新颖的跨尺度方法来完成，应用结合壳宏观结构（形状）和微观结构材料特性的有限元分析建模，并验证现代和化石壳的分析。这项研究将产生一个理论形态空间，量化一系列外壳形状和微观结构组合的防御能力。从这项研究中产生的模型框架将在捕食者-猎物驱动的进化、保护古生物学和材料科学的研究中具有基础应用。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，这极有可能对软体动物和鱼类产生负面影响。这项研究将为超越现代生态研究的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、抗裂的生物灵感材料产生影响。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 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.