CAREER: Mechanisms and drivers underlying thermal specialization patterns in elastic recoil and muscle powered movements

该奖项的部分资金来自2021年美国救援法案（公法117-2）。此外，该项目由生物科学理事会综合有机系统部的生理机制和生物力学计划以及刺激竞争研究的既定计划（EPSCoR）共同资助。动物在其环境中表现良好的能力是完成其许多最基本和重要功能的核心。由于这些能力-以及允许它们的动物的身体特征-经过数千代的缓慢进化，快速变化的环境挑战了动物的反应和适应能力。动物环境的一个关键特征是温度，特别是对于像变色龙这样的冷血动物来说，它们依靠环境中的热量将身体加热到最佳工作温度，同时在太热时寻求降温的方法。为了研究温度如何影响变色龙的一项基本能力--用舌头进食--该项目测量了不同种类的非洲变色龙所经历的环境温度范围，这些不同的栖息地如何对应于进食表现的差异，进食的差异如何与舌头肌肉和结缔组织的温度敏感性差异有关，以及这些差异是如何演变的此外，这项研究利用了变色龙的魅力和它们喂食的高速视频的迷人视觉效果来吸引和教育广大观众。特别是，这些成果将被纳入为解决生物和物理科学的具体K-12学习目标而开发的教育模块。具体而言，作为课程增强资源的一部分，开发连接科学家在南达科他州的农村和部落社区的教师和教室，这项研究将导致免费的课程模块的基础上发生在南达科他州的高等教育机构的科学研究与南达科他州科学标准。在这个过程中，本研究将形成一个基础，通过开发新的实验室模块，原始的案例研究材料，和新的课程设置，在本科和研究生水平的新课程的开发内容。温度表现出强烈的影响，通过其对肌肉收缩动力学的动物运动和性能。然而，由弹性组织的反冲提供动力的运动与直接由肌肉收缩提供动力的运动对环境温度变化的反应不同。因此，这些系统及其潜在的功能过程也可能经历与其环境的热专业化有关的不同选择压力。这个项目将比较两种运动类型的热专业化模式：变色龙的弹性反冲动力舌头投射和肌肉动力舌头缩回。这些比较将侧重于检查整个生物体性能的热敏感性以及产生这些运动所涉及的不同潜在机械过程（例如，运动控制，肌肉收缩生理学，解剖学变化）的变色龙生活在不同的热环境。结合生态工作在现场和实验室中的实验工作，这项工作将确定在何种程度上不同类型的运动进行热专业化，在什么样的机械水平热专业化发生的两种运动类型，什么环境因素驱动这些模式，在何种程度上驯化影响性能在这两个运动，以及在这些模式的进化趋势。在这个过程中，这项研究将深入了解动物如何使用不同类型的运动来实现关键的生态功能，从而应对环境条件的变化。我们对适应不同和不断变化的环境条件（特别是温度）的理解的这些进步将影响生态学，生理学和进化生物学领域。此外，该工作还包括广泛的外展工作、教育活动、科学报告和出版物，以及对本科生、研究生和博士后研究人员的研究培训。该奖项反映了NSF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 part under the American Rescue Act of 2021 (Public Law 117-2). In addition, this project is jointly funded by the Physiological Mechanisms and Biomechanics Program in the Division of Integrative Organismal Systems in the Biological Sciences Directorate and by the Established Program to Stimulate Competitive Research (EPSCoR).The ability of an animal to perform well in its environment is central to accomplishing many of its most basic and important functions. Since those abilities--and the physical features of the animals that permit them--evolved slowly over thousands of generations, rapidly changing environments challenge the ability of animals to respond and adapt. A key feature of an animal’s environment is temperature, particularly for cold-blooded animals like chameleons, who rely on heat from the environment to warm their bodies to the best operating temperature while seeking ways to cool off when it gets too hot. To investigate how the temperature impacts a fundamental ability--the chameleon’s feeding with its projectile tongue--this project measures the range of environmental temperatures experienced by different species of African chameleons, how those different habitats correspond to differences in feeding performance, how differences in feeding are related to differences in the temperature sensitivity of the muscles and connective tissues of the tongue, and how those differences might have evolved. In addition, this research harnesses the charismatic nature of chameleons and the captivating visuals of high-speed video of their feeding to engage and educate a broad audience. In particular, these results will be integrated into education modules developed to address specific K-12 learning objectives in the biological and physical sciences. Specifically, as part of a curriculum enhancement resource developed to connect scientists to teachers and classrooms in rural and tribal communities in South Dakota, this research will result in free curriculum modules based on scientific research occurring in South Dakota’s higher education institutions that are aligned with the South Dakota Science Standards. In the process, this research will form a foundation for developing content for new curricula offerings at the undergraduate and graduate level through the development of novel laboratory modules, original case study materials, and new course offerings.Temperature exhibits strong effects on animal movement and performance through its effect on muscle contractile dynamics. Movements powered by the recoil of elastic tissues, however, respond differently to changes in environmental temperature than movements powered by muscle contraction directly. These systems and their underlying functional processes therefore may also experience different selection pressures relating to thermal specialization to their environment. This project will compare patterns of thermal specialization in two movement types: elastic recoil-powered tongue projection and muscle-powered tongue retraction in chameleons. These comparisons will focus on examining the thermal sensitivity of whole organism performance and the different underlying mechanistic processes involved in producing these movements (e.g., motor control, muscle contractile physiology, anatomical variation) in chameleons living in different thermal environments. Combining ecological work in the field and experimental work in the laboratory, this work will determine to what extent different types of movement undergo thermal specialization, at what mechanistic level thermal specialization occurs for both movement types, what environmental factors drive these patterns, the extent to which acclimation affects performance in both movements, and evolutionary trends in these patterns. In the process, this research will provide insight into how animals using different types of movement for critical ecological functions may respond to shifts in environmental conditions. These advancements in our understanding of adaptation to differing and changing environmental conditions, particularly temperature, will impact the fields of ecology, physiology, and evolutionary biology. In addition, the work includes broad outreach efforts, educational activities, and scientific presentations and publications, with research training for undergraduates, graduate students, and a postdoctoral researcher.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.