QUASI-11 YEAR MODULATION OF GLOBAL AND SPECTRAL FEATURES OF GEOMAGNETIC DISTURBANCE

Variations in spectral characteristics of the K-p-index of geomagnetic activity during the solar activity cycle were studied in order to ass ess the role of its rhythms in the formation of temporal structure of biological objects. It is shown that most spectral components of the K -p-index are mdulated by the 10.5-year periodic rhythms in solar activ ity variations, while its circasemiseptan component (3.5 days) exhibit s an 11-year rhythm. Since it: is a circasemiseptan rhythm that is cha racteristics of biological objects (e.g., unicellular algae), it: can be assumed that geophysical rhythms played a substantial role in the f ormation of biological rhythms during evolution.