DISSERTATION RESEARCH: Gliding Aerodynamics and the Origin of Bat Flight

滑翔空气动力学与蝙蝠飞行的起源。Swartz和Kristin Bishop一个很好地适应一种功能的结构如何演变成一个适应不同功能的新结构，而没有一个功能性的中间阶段，这个问题继续挑战着进化生物学家。 这种转变的一个例子是蝙蝠从滑翔祖先进化出飞行能力。 一种假设是，哺乳动物滑翔机的短而宽的翅膀在扑翼飞行时不能产生足够的升力。 相反，很少有蝙蝠会定期滑翔，因此，第二个假设是，细长的蝙蝠翅膀不适合滑翔。 空气动力学理论主要集中在人类设计的飞机上，因此对哺乳动物滑翔机和蝙蝠等小型，灵活，缓慢移动的翅膀知之甚少。 为了更好地了解蝙蝠飞行的演变，在本研究中，将通过建立从滑翔机到蝙蝠的连续体的翅膀物理模型来测试翅膀形状对小而灵活的翅膀的空气动力学的影响。 将在风洞中测量在生物学上真实的风速下产生的升力和阻力。为了确定蝙蝠飞行的起源，了解现存哺乳动物滑翔的机制也很重要。 滑翔在六个独立的哺乳动物群体中独立进化，它们都有相似的身体形状和行为。 这有力地表明，蝙蝠的任何滑翔祖先也具有这些特征，对滑翔哺乳动物的研究可以为蝙蝠祖先提供重要的见解。通过对三组滑翔类哺乳动物滑翔运动的三维运动分析，进一步了解哺乳动物的滑翔行为。这些信息，结合物理模型数据，将允许在相关的生物背景下评估机翼形状的重要性。

Gliding aerodynamics and the Origin of Bat FlightBy Sharon M. Swartz and Kristin BishopThe question of how a structure that is well adapted for one function evolves into a new structure adapted for a different function without a functional intermediate phase continues to challenge evolutionary biologists. One example of this kind of transition is the evolution of flight in bats from a gliding ancestor. One assumption is that short, broad wings of living mammalian gliders cannot generate enough lift if they are used in flapping flight. Conversely, few bats glide routinely, a second assumption, therefore, is that long, slender bat wings do not work well for gliding. Aerodynamic theory has focused on human-engineered aircraft, so very little is known about small, flexible, slow moving wings such as those of mammalian gliders and bats. To better understand the evolution of flight in bats, the effect of wing shape on the aerodynamics of small, flexible wings will be tested in the present study by building physical models of wings that span a continuum from glider-like to bat-like. The lift and drag forces that are generated at biologically realistic wind speeds will be measured in a wind tunnel. To determine the origin of flight in bats, it is also important to understand the mechanisms of gliding in living mammals. Gliding evolved independently in six separate groups of living mammals that all share similar body shapes and behaviors. This strongly suggests that any gliding ancestor of bats also shared these features, and that the study of gliding mammals can give important insights into bat ancestors. Three-dimensional motion analysis of gliding in three groups of gliding mammals will be used to learn more about gliding behavior in mammals. This information, combined with the physical model data, will allow assessment of the importance of wing shape in a relevant biological context.