Respiratory protein-driven selectivity during the Permian-Triassic mass extinction
Haijun Song, Yuyang Wu, Xu Dai, Jacopo Dal Corso, Feng‐Yu Wang, Yan Feng, Daoliang Chu, Li Tian, Huyue Song, William J. Foster, Huyue Song, William J. Foster
Abstract
Extinction selectivity determines the direction of macroevolution, especially during mass extinction; however, its driving mechanisms remain poorly understood. By investigating the physiological selectivity of marine animals during the Permian-Triassic mass extinction, we found that marine clades with lower O 2 -carrying capacity hemerythrin proteins and those relying on O 2 diffusion experienced significantly greater extinction intensity and body-size reduction than those with higher O 2 -carrying capacity hemoglobin or hemocyanin proteins. Our findings suggest that animals with high O 2 -carrying capacity obtained the necessary O 2 even under hypoxia and compensated for the increased energy requirements caused by ocean acidification, which enabled their survival during the Permian-Triassic mass extinction. Thus, high O 2 -carrying capacity may have been crucial for the transition from the Paleozoic to the Modern Evolutionary Fauna.