Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu 432-8561, Japan.
Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561, Japan.
Sci Rep. 2017 Feb 10;7:42445. doi: 10.1038/srep42445.
Bivalve, ammonite and snail shells are described by a small number of geometrical parameters. Raup noted that the vast majority of theoretically possible shell forms do not occur in nature. The constraint factors that regulate the biased distribution of natural form have long since been an open problem in evolution. The problem of whether natural shell form is a result of optimization remains unsolved despite previous attempts. Here we solve this problem by considering the scaling exponent of shell thickness as a morphological parameter. The scaling exponent has a drastic effect on the optimal design of shell shapes. The observed characteristic shapes of natural shells are explained in a unified manner as a result of optimal utilization of shell material resources, while isometric growth in thickness leads to impossibly tight coiling.
双壳类、菊石类和蜗牛壳的形状可以用少数几个几何参数来描述。劳普注意到，绝大多数理论上可能的壳形在自然界中都没有出现。长期以来，调节自然形态的偏态分布的约束因素一直是进化中的一个开放性问题。尽管之前有人尝试解决这个问题，但自然壳形是否是优化的结果仍然没有得到解决。在这里，我们通过考虑壳厚度的标度指数作为形态参数来解决这个问题。该标度指数对壳形状的最佳设计有重大影响。由于对壳材料资源的最优利用，自然壳的观察到的特征形状得到了统一的解释，而等厚生长则导致不可能出现紧密的螺旋状。
