Energy Conservation and the Evolution of Flightlessness in Birds
Energy Conservation and the Evolution of Flightlessness in Birds
复制标题
能量守恒和鸟类不会飞的进化
作者：
B. McNab
我通过比较与猕猴桃、有飞行和无飞行的铁轨和鸭子的基础代谢率相关的因素，检验了能量节约有助于鸟类无法飞行状况进化的假设。不能飞的铁轨有较低的基础率，其水平随着胸肌质量而降低。几维鸟也有低基础率和小胸肌群众。在不会飞的、不会飞的鸬鹚和不会飞的鹦鹉中发现的小胸肌块表明这些物种的基础率较低。与此相反，企鹅和不会飞的鸭子既没有低的基础率，也没有小的胸肌，因为这些鸟类使用翅膀运动。这些数据是兼容的假设，即能量守恒有助于物种中的胸肌质量减少的flightless的演变。在海洋岛屿上，秧鸡已经反复进化出不能飞行的状态，通常与较小的身体尺寸有关。这两种调整都减少了能量消耗，从而促进了轨道在资源有限的环境中的持久性。昆虫不能飞的进化也可能是对有限资源可用性的一种反应，特别是在以低生产率为特征的持久栖息地。
I examine the hypothesis that energy conservation contributes to the evolution of a flightless condition in birds by comparing the factors that correlate with basal rate of metabolism in kiwis and flighted and flightless rails and ducks. Flightless rails have low basal rates, the level of which decreases with pectoral muscle mass. Kiwis also have low basal rates and small pectoral masses. The small pectoral masses found in flightless grebes, the flightless cormorant, and the flightless parrot suggest that these species have low basal rates. Penguins and flightless ducks, in contrast, have neither low basal rates nor small pectoral masses because these birds use their wings for locomotion. These data are compatible with the hypothesis that energy conservation contributes to the evolution of flightlessness in species in which pectoral muscle mass is reduced. On oceanic islands, rails have evolved a flightless condition repeatedly, usually in association with a small body size. Both adjustments reduce energy expenditure, which thereby facilitates the persistence of rails in environments with limited resources. The evolution of flightlessness in insects may also be a response to a restricted resource availability, especially in persistent habitats characterized by low rates of production.