. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ir n "u w- vv • |D H, Q fl£ C _ n n° •• »• * ^ n Strain Rate (s-1) d. g S 2 in en 01 CD z ai 1-. ffi Strain Rate i Figure 2. Breaking force (a), nominal strength (b). breaking strain (c). and nominal stiffness (d) are plotted on a log-log scale against strain rate for oral (crosses, dotted line), ambitul (filled circles, dashed line), and aboral (open squares, solid line) podia. Lines are least-squares linear regressions. Line slopes and elevations were compared by ANCOVA (Table 2). rates, and aboral p
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ir n "u w- vv • |D H, Q fl£ C _ n n° •• »• * ^ n Strain Rate (s-1) d. g S 2 in en 01 CD z ai 1-. ffi Strain Rate i Figure 2. Breaking force (a), nominal strength (b). breaking strain (c). and nominal stiffness (d) are plotted on a log-log scale against strain rate for oral (crosses, dotted line), ambitul (filled circles, dashed line), and aboral (open squares, solid line) podia. Lines are least-squares linear regressions. Line slopes and elevations were compared by ANCOVA (Table 2). rates, and aboral podia were significantly stiffer than oral podia at all strain rates; r values for these regressions ranged from to Discussion Some of the morphological differences found among the podia of other urchins (, presence versus absence of suckers) are absent in Strongylocentrotus droebachiensis, possibly because the aboral podia, in addition to acting as a respiratory surface, perform other functions that require suckers. For example, drift algae captured by aboral podia may be the primary food source for some urchins (De Ridder and Lawrence, 1982). Furthermore, urchins like S. droebachiensis, that live in high-flow environments, may require suckered aboral podia to secure themselves in cracks and to right themselves (Fenner, 1973). Thus, aboral podia, though performing a different set of tasks from oral podia, would still require the same gross morphology. Although all podia in S. droebachiensis do possess suck- ers, they still exhibit mechanical and morphological differ- entiation consistent with their location and functional spe- cialization for locomotion or respiration. The greater strength and thicker walls of the oral podia presumably enhance one of their primary functions, which is to resist hydrodynamically generated forces on the urchin (Denny and Gaylord, 1996). Similarly, the thin walls of the aboral. Please note that these images are extracted f
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
