. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 43. 41 FIGURE 2. Drag and surface area indexes for larval models. Columns I and II contain eight different models for which drag was measured empirically. Columns I' and II' show Stokes" diameters of spheres, plotted as solid circles, which have equivalent drag to models in the adjacent columns. The dotted circles represent spheres which have equivalent surface area to models in the adjacent columns. Numbers on the models refer to the models' dimensions, in mm (50X life size); numbers inside the circles refer to the dia
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 43. 41 FIGURE 2. Drag and surface area indexes for larval models. Columns I and II contain eight different models for which drag was measured empirically. Columns I' and II' show Stokes" diameters of spheres, plotted as solid circles, which have equivalent drag to models in the adjacent columns. The dotted circles represent spheres which have equivalent surface area to models in the adjacent columns. Numbers on the models refer to the models' dimensions, in mm (50X life size); numbers inside the circles refer to the diameter of equivalent surface area spheres. Numbers below the circles refer to diameters of spheres of equivalent drag. L == length of arm == 320, 800, or 1600 V := swimming velocity - 10~3 m/s a == radius of arm =: 10 A swimming velocity of 1 mm/s is probably high for a larva with 1600 ^m long arms, but the plutei of species mentioned above swim at or near this speed (Emlet, pers. ob.). Since no information exists on swimming velocity changes with size in plutei, I assumed 1 mm/s for all sizes. Drag on the arms must be summed with body drag (scaled using Stokes' diameter for the empirical measurements discussed above). Figure 3 shows the relationship between equivalent Stokes' diameter, arm length, arm number, and arm orientation. The model for forces generated in swimming To test the hypothesis that fenestrated spicules are necessary to support longer arms, forces produced during swimming were calculated and resolved into bending forces on the arms. According to the ciliary sublayer model (Blake, 1972; Roberts, 1981), the total force required to generate the ciliary currents during swimming has two components, Fc and Fd. Fc (ciliary force) is the force required to maintain the shear gradient in the ciliary layer. Since the fluid at the tips of the cilia shears with respect to fluid external to it, there is the additional component of drag, Fd (drag force), whose maximum value i
Size: 1522px × 1642px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
