Evolution of a functionally robust, high-performance musculoskeletal system

环境温度对动物的生理过程有很大影响，例如两栖动物的体温是由环境决定的。这种体温外动物的活动受到低温下生理过程减慢的限制，特别是肌肉收缩的速度和力量。与肌肉运动的热敏感性不同，一些体温外动物的弹道进食运动几乎不受环境温度的影响。凭借弹性后坐机构，在广泛的温度范围内，性能都保持在高水平。这种“弓和箭”的机制允许肌肉缓慢收缩并拉伸肌腱状结构，这些结构随后迅速回缩，为运动提供动力。由于胶原蛋白弹性回弹的速度比肌肉收缩的速度对温度的敏感度低得多，这种弹性驱动的运动表现出更强的热稳定性，潜在地扩大了动物的温度范围。这项研究将考察弹性动力运动中高性能和热稳定性演变的生理学基础。这项研究将集中在集成系统的性能以及潜在的运动控制、形态、生物力学和肌肉收缩生理学方面的进化转变。这项研究还将检验这一假设，即弹性系统是通过修改现有的解剖结构而不是通过肌肉生理学的根本变化从非弹性系统进化而来的。弹性反冲的一般模型将被应用于一个焦点外热系统--火蜥蜴的弹道进食--在这个系统中，极端的性能和热稳定性已经并行进化了多次。这项研究将对具有和不具有弹性组件的其他不同肌肉骨骼系统对环境挑战的稳健性进行可测试的预测。研究生、本科生和博士后将接受广泛的科学技能和活动方面的培训，包括实地和实验室程序、参加科学会议和传播成果。将开发弹性系统(火蜥蜴中的弹道进食)的交互式在线模拟，以供教学和外行使用。与当地的K-12教师和墨西哥的一名生物学教授合作，将为美国和墨西哥的研究人员、教师和学生提供培训以及实验室和实地经验。教师的研究经验将促进K-12科学教育工作者的发展，并支持将新的研究成果在跨课程框架下交付给大而多样的学区的教室。

Environmental temperature has strong effects on the physiological processes of animals such as amphibians whose body temperature is determined by their surroundings. Activity of such ectothermic animals is limited by the slowing of physiological processes at low temperatures, notably the speed and power of muscle contraction. In contrast to the thermal sensitivity of muscle-powered movements, the ballistic feeding movements of some ectothermic animals are scarcely affected by environmental temperature. Performance is maintained at a high level across a broad range of temperatures by virtue of an elastic-recoil mechanism. This 'bow and arrow' mechanism allows muscles to contract slowly and stretch tendon-like structures, which subsequently recoil rapidly to power movement. Because the speed of elastic recoil of collagen has a much lower temperature sensitivity than the speed of muscle contraction, such elastically powered movements display greater thermal robustness, potentially expanding the animal's thermal range. This research will examine the physiological basis for the evolution of high performance and thermal robustness in elastically powered movements. The research will focus on evolutionary transitions in performance of the integrated system as well as in the underlying motor control, morphology, biomechanics, and muscle contractile physiology. This study will also test the hypothesis that elastic systems evolve from non-elastic systems via the modification of existing anatomical structures rather than through fundamental changes in muscle physiology. A generalized model of elastic recoil will be applied to a focal ectothermic system--ballistic feeding in salamanders--in which extreme performance and thermal robustness have evolved multiple times in parallel. The research will make testable predictions about the robustness to environmental challenges of other diverse musculoskeletal systems with and without elastic components. Graduate, undergraduate and postdoctoral students will be trained in a wide range of scientific skills and activities, including field and laboratory procedures, participation at scientific meetings, and dissemination of results. An interactive online simulation of an elastic system (ballistic feeding in a salamander) will be developed to be used in teaching and by laypersons. Partnership with local K-12 teachers and a biology professor in Mexico will provide training as well as laboratory and field experiences to US and Mexican researchers, teachers and students. Research experiences for teachers will enhance the development of K-12 science educators and support the delivery of new research findings in a cross-curricular framework to classrooms in a large and diverse school district.