被子植物の進化的成功：生物エネルギー余剰の基盤

The global ecological dominance of angiosperms represents a major evolutionary success. This study suggests that their ascendance is not due to a single trait but to a deeply integrated hydraulic design that maximizes performance and resilience. A model is developed, and based on the constructal law, the leaf vascular architecture of three major plant lineages, angiosperms, gymnosperms, and ferns is compared. The model evaluates performance based on two foundational parameters: the branching exponent which accounts for the supply efficiency, and the vein placement ratio, which controls water distribution. The results demonstrate that the angiosperm architecture is superior across all modeled metrics. This design minimizes the energetic cost of water transport, ensures uniform water distribution, and enables rapid hydraulic responsiveness. Significantly, the model reveals that this profound efficiency generates a bioenergetic surplus that funds a resilient, redundant vascular network. This fault-tolerant design provides a decisive advantage against physical damage, ensuring that high photosynthetic capacity is a sustained reality rather than a fragile state. It is this synergistic system that provides a quantitative explanation for the enduring global supremacy of angiosperms.