Department of Biology and Program in Cognitive Science, Vassar College, Poughkeepsie, NY 12604, USA.
Integr Comp Biol. 2010 Dec;50(6):1120-39. doi: 10.1093/icb/icq066. Epub 2010 Jun 24.
The bodies of fish change shape over propulsive, behavioral, developmental, and evolutionary time scales, a general phenomenon that we call "reconfiguration". Undulatory, postural, and form-reconfiguration can be distinguished, studied independently, and examined in terms of mechanical interactions and evolutionary importance. Using a combination of live, swimming fishes and digital robotic fish that are autonomous and self-propelled, we examined the functional relation between undulatory and postural reconfiguration in forward swimming, backward swimming, and yaw turning. To probe how postural and form reconfiguration interact, the yaw turning of leopard sharks was examined using morphometric and kinematic analyses. To test how undulatory reconfiguration might evolve, the digital robotic fish were subjected to selection for enhanced performance in a simulated ecology in which each individual had to detect and move towards a food source. In addition to the general issue of reconfiguration, these investigations are united by the fact that the dynamics of undulatory and postural reconfigurations are predicted to be determined, in part, by the structural stiffness of the fish's body. Our method defines undulatory reconfiguration as the combined, point-by-point periodic motion of the body, leaving postural reconfiguration as the combined deviations from undulatory reconfiguration. While undulatory reconfiguration appears to be the sole or primary propulsive driver, postural reconfiguration may contribute to propulsion in hagfish and it is correlated with differences in forward, and backward, swimming in lamprey. Form reconfigures over developmental time in leopard sharks in a manner that is consistent with an allometric scaling theory in which structural stiffness of the body is held constant. However, correlation of a form proxy for structural stiffness of the body suggests that body stiffness may scale in order to limit maximum postural reconfiguration during routine yaw turns. When structural stiffness and undulatory frequency are modeled as determining the tail's undulatory wave speed, both factors evolve under selection for enhanced foraging behavior in the digital fish-like robots. The methods used in making these distinctions between kinds of reconfiguration have broad applicability in fish biology, especially for quantifying complex motor behaviors in the wild and for simulating selection on behavior that leads to directional evolution of functional phenotypes.
鱼类的身体在推进、行为、发育和进化的时间尺度上改变形状，这是一种普遍现象，我们称之为“重新配置”。可以区分波动、姿势和形态重新配置，可以独立研究，并根据机械相互作用和进化重要性进行检查。我们使用游动的活鱼和自主自推进的数字机器鱼的组合，研究了前向游泳、后向游泳和偏航转弯中波动和姿势重新配置之间的功能关系。为了探究姿势和形态重新配置如何相互作用，我们使用形态测量和运动学分析来研究豹鲨的偏航转弯。为了测试波动重新配置如何进化，数字机器鱼受到了在模拟生态中增强性能的选择，在该生态中，每个个体都必须检测并向食物源移动。除了重新配置的一般问题外，这些研究还因波动和姿势重新配置的动力学部分由鱼体的结构刚度决定这一事实而联合起来。我们的方法将波动重新配置定义为身体的组合、逐点周期性运动，将姿势重新配置定义为波动重新配置的组合偏差。虽然波动重新配置似乎是唯一或主要的推进驱动因素，但姿势重新配置可能有助于盲鳗的推进，并且与七鳃鳗的前向和后向游泳差异相关。豹鲨的形态在发育过程中重新配置，方式与身体结构刚度保持不变的一种比例缩放理论一致。然而，身体结构刚度的形态代理与身体结构刚度相关，这表明身体刚度可能会缩放，以限制常规偏航转弯期间的最大姿势重新配置。当结构刚度和波动频率被建模为确定尾巴的波动波速时，这两个因素都在数字鱼形机器人中增强觅食行为的选择下进化。在鱼类生物学中，特别是在量化野生复杂运动行为和模拟导致功能表型定向进化的行为选择方面，这些区分重新配置类型的方法具有广泛的适用性。
