Evolution of marine palaeoecosystems and stratigraphical correlation

Based on the analysis of evolution trends and diversity dynamics of the number of widespread Paleozoic animals in the Northern Eurasia the important, and often crucial, role of event-driven phenomena has been determined for these processes. The reason for crises in the evolution of the regional fossil biota, causing the rebuilding of community structure and extinctions, was, first of all, considerable change of habitat conditions or complete abandoning of biotops resulted from climate changes or sharp fluctuations of global ocean level.