Figure 24.14 A Brief History of Multicellular Life on Earth The geologically rapid “explosion” of life shortly before and during the Cambrian saw the rise of many major animal groups that have representatives surviving today. The following three pages depict life’s history through the Phanerozoic. The movements of the major continents during the past half-billion years are shown in the maps of Earth, and associated biotas for each time period are depicted. The artists’ reconstructions are based on fossils such as those shown in the photographs.