Multistage evolution of Metazoa

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We obtained chemostratigraphies of C, O, Sr, Fe and Ca isotopes and Fe, Mn, REE and P contents of carbonates, Mo isotopes of black shales and C and N of organic matter from the Ediacaran to the Early Cambrian to estimate primary productivity, continental influx, temperature, nutrient contents, and redox condition of seawater, using twenty-four drill cores in South China. The results suggest that the emergence of Metazoan was caused under the less oxic and P-rich condition, whereas the diversification occurred under oxic, nitrate and Ca-rich condition. Especially, the transition from P to nitrate-rich seawater contributed to more actively mobile metazoans through increase in Redfield ratio. The biological evolution occurred just after increase in nutrients, allowing a new insight of biological evolution of metazoans. The quick response of biological evolution to the environments suggests that the fundamental base for biological functions were already established before the emergence.