The chaos in human body provides a sort of healthy adaptability, it seems to be the reflection of selection and adaptability in the process of the evolution of the life. Then, can the chaos be regarded as a motive power of the process of the evolution of species? In answer to this, the experiments have been conducted on sample cardioelectrical signals of human being and the canines, Through the analyses of the power spectra to a large of cardioelectrical signals, the following conclusions are shown:(1) The analyses of the power spectra to cardioelectrical signals reflect the whole dynamic characteristics of the heart, it may become a new method as a sort of quantitative researches on eletrocardiogram to early diagnose the heart disease. (2) Under normal physiological conditions the cardiac activities are chaotic, however under pathologic conditions the cardiac activities approach regularity. (3) On the basis of the comparative research of human being and the canines, the hypothesis is proposed that chaos would become more significant in the warke of the evolution of species. If the hypothesis is right, it would be a beginning of the new theory on the evolution of species.