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》(公法117-2)。此外，这个项目由生物科学局综合组织系统司的生理机制和生物力学计划和既定的刺激竞争研究计划(EPSCoR)共同资助。动物在其环境中良好表现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--在几千代人的时间里进化得很慢，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，同时在天气太热时寻找降温的方法。为了研究温度如何影响变色龙的基本能力--变色龙用其突出的舌头进食--这个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性能的差异，进食的差异如何与舌头肌肉和结缔组织的温度敏感度的差异有关，以及这些差异可能是如何演变的。此外，这项研究利用变色龙的魅力和它们觅食的高速视频的迷人视觉来吸引和教育广泛的受众。特别是，这些成果将被纳入为解决生物科学和物理科学中具体的K-12学习目标而开发的教育单元。具体地说，作为为将科学家与南达科他州农村和部落社区的教师和教室联系起来而开发的课程增强资源的一部分，这项研究将产生基于南达科他州高等教育机构的科学研究的免费课程模块，这些机构与南达科他州科学标准保持一致。在这个过程中，这项研究将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，为本科生和研究生水平的新课程提供内容奠定基础。温度通过对肌肉收缩动力学的影响，对动物的运动和表现表现出强烈的影响。然而，由弹性组织的回弹驱动的运动与直接由肌肉收缩驱动的运动对环境温度变化的反应不同。因此，这些系统及其基本功能过程也可能面临与其环境的热专门化有关的不同选择压力。这个项目将比较变色龙两种运动类型的热专门化模式：弹性后坐力驱动的舌头投射和肌肉动力的舌头缩回。这些比较将集中于考察整个生物体表现的热敏感性，以及在不同热环境中生活的变色龙产生这些运动的不同潜在机械过程(例如，运动控制、肌肉收缩生理学、解剖变异)。结合野外的生态学工作和实验室的实验工作，这项工作将确定不同类型的运动经历多大程度的热专门化，两种运动类型在什么机械水平上发生热专门化，什么环境因素驱动这些模式，驯化对两种运动的表现的影响程度，以及这些模式的进化趋势。在这个过程中，这项研究将为使用不同类型的运动来执行关键生态功能的动物如何应对环境条件的变化提供洞察力。我们对适应不同和不断变化的环境条件，特别是温度的适应方面的这些进展，将影响生态学、生理学和进化生物学领域。此外，这项工作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智力优势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.