Form and Function of Hearts and Toes

作为一名比较生理学家，我的研究重点是通过跟踪动物王国器官系统的功能形态，或在运动和潜水能力的生物范围的极端情况下研究动物的生理学，来研究系统发育过程在塑造动物环境中的作用。在器官系统的功能形态学方面，我将研究海龟的心脏，它可以说是所有海龟中最活跃的，还有鸸鹋，它们的头远远高于心脏，必须补偿重力的影响。为什么这些动物有趣？我们基于形态学和古生物学系统发生学对爬行动物心脏进化的看法，已经被分子系统发生学的出现所颠覆。海龟已经失去了在系统发育的基础上的地位，现在被置于蛇和蜥蜴之中。我研究过蜥蜴的心脏，现在打算研究海龟的心脏结构和功能，通过经食道超声和磁共振成像对活体心脏的研究，寻找解剖和生理上的关系。头部高过心脏意味着心脏必须更加努力地泵血以产生高血压，这样血管才不会塌陷并停止流动。所有长颈动物都有很大的心脏，这表明它们可以在高压下泵血，但到目前为止，还没有人记录过有行为的动物的压力。我建议记录下不受约束的鸸鹋的动脉血压，并将其与头部在心脏上方或下方的位置联系起来。在鸭子潜水领域，最有趣的一个方面是没有人知道潜水组成部分的实际能量消耗（下降，在底部保持进食和上升）。所做的功是力乘以移动的距离，所以下降和上升都很容易，但在底部，鸭子继续划水以保持自己的位置。因此，没有移动距离，没有完成任何工作，但鸭子看起来很努力。我们建议通过测量在划水过程中移动脚所做的功来模拟潜水时所做的功，所以我们有一个移动的距离！本研究对今后潜水生态生理学的研究具有重要意义。

As a comparative physiologist, I have focused my research on the role of phylogenetic processes in shaping an animal for its environment by tracking the functional morphology of organ systems across the animal kingdom or studying the physiology of animals at the extremes of the biological range of exercise and diving capabilities. In respect to functional morphology of organ systems, I will be looking at the heart of sea turtles, arguably the most active of all turtles, and emus which raise their heads way above their hearts and have to compensate for gravitational effects. Why are these animals interesting? Our view of evolution of the reptilian heart, based on morphological and paleontological phylogenies, has been upset by the advent of molecular phylogenies. Turtles have lost their place at the base of the phylogeny and are now placed among the snakes and lizards. I have researched lizard hearts and now propose to investigate heart structure and function in sea turtles, looking for anatomical and physiological relationships by investigations of the living heart by trans-oesophageal ultrasound and magnetic resonance imaging. A head held high above the heart means that the heart has to pump much harder to create a high blood pressure so the blood vessels don't collapse and stop flow. All long necked animals have large hearts suggesting they can pump at high pressures but, to date, nobody has ever recorded pressure from a behaving animal. I propose to record arterial blood pressure from unrestrained emus and correlate it to the position of the head above or below the heart. In the duck diving field, one of the most intriguing aspects is that nobody knows the actual energetic cost of the dive components (descent, holding at the bottom to feed and ascent). Work done is force multiplied by distance moved so descent and ascent are easy but, at the bottom, ducks continue paddling to hold their position. Hence, no distance moved, no work done but the ducks look to be working hard. We are proposing to model the work done during diving by measuring the work done by moving the feet through the water during paddling, so we have a distance moved! This research will be indispensable to future studies of the eco-physiology of diving.