Kooloos J G, Zweers G A
Department of Neurobehavioural Morphology, University of Leiden, The Netherlands.
Acta Biotheor. 1991 Jun;39(2):107-40. doi: 10.1007/BF00046595.
This paper is one of several contributions in a series, illustrating the application of a specific deductive methodology to explain diversity of form. The methodology facilitates the explanation of feeding morphologies in various ducks as a transformation of the mallard's feeding design maximized for specific proportions of performance that are contributed by pecking and filter feeding mechanisms. The earlier described anatomy and formal analyses of the three mechanisms in the mallard served as the initial conditions used in simulation models. Four elements of the feeding system were chosen that play a major role in all three mechanisms. For each element, the main parameter was selected: storage capacity of the rostral mouth cavity, transport capacity of the rostral mouth tube, storage capacity of the caudal mouth cavity and transport capacity of the caudal mouth tube. The boundary conditions for the simulation were determined from internal organismic constraints. The total food uptake of the mallard was regarded as the function to be maximized. This 'object' function is the summation of the food uptake by one second of pecking and one second of filter feeding. The drinking mechanism was shown not to interfere, since that mechanism operates sufficiently whenever the pumping mechanism works properly. The 'object' function, made up by the pecking and filter feeding performances was graphed. From these graphs a morphospace was developed: the region within which modifications of the mouth design are feasible. This procedure allowed examination of the general hypothesis that different modifications of one design for a complex multi-role system are explainable from differences in proportions of the functional performance contributed by each of the roles. Two predictions were evaluated more specifically: 1) If filter feeding performance must increase for a specific change in total food uptake, the volume of the rostral mouth cavity must increase; this requires widening and lengthening of the rostral maxillar portion and also a phase shift in jaw and lingual motion patterns, increasing the stroke volume. 2) If pecking performance must increase, the transport capacity of the rostral mouth tube must increase; this requires shortening of the maxillar mid portion. These two predictions regarding change in mouth morphology were borne out by shovelers and tufted ducks, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)
本文是一系列论文中的一篇，阐述了一种特定演绎方法在解释形态多样性方面的应用。该方法有助于解释各种鸭子的进食形态，即野鸭进食设计的一种转变，这种转变是为了使啄食和滤食机制所贡献的特定性能比例达到最大化。之前所描述的野鸭三种机制的解剖结构和形式分析，作为模拟模型的初始条件。选取了在所有三种机制中起主要作用的四个进食系统要素。对于每个要素，选定了主要参数：喙端口腔的储存容量、喙端口管的输送容量、喙后端口腔的储存容量以及喙后端口管的输送容量。模拟的边界条件由机体内部限制因素确定。野鸭的总食物摄入量被视为要最大化的函数。这个“目标”函数是一秒钟啄食和一秒钟滤食所摄入食物量的总和。研究表明饮水机制不会产生干扰，因为只要泵送机制正常工作，饮水机制就能充分发挥作用。由啄食和滤食性能构成的“目标”函数被绘制成图。根据这些图表构建了一个形态空间：即口部设计修改可行的区域。这个过程使得人们能够检验这样一个普遍假设，即对于一个复杂的多角色系统，一种设计的不同修改可以通过每个角色所贡献的功能性能比例差异来解释。对两个预测进行了更具体的评估：1）如果为了总食物摄入量的特定变化而必须提高滤食性能，那么喙端口腔的体积必须增大；这需要喙端上颌部分变宽变长，同时颌骨和舌部运动模式发生相位变化，增加冲程容积。2）如果必须提高啄食性能，那么喙端口管的输送容量必须增加；这需要缩短上颌中部。关于口部形态变化的这两个预测分别在琵嘴鸭和凤头潜鸭身上得到了证实。（摘要截断于400字）
