Evidence of hierarchical organization in the planktic foraminiferal evolutionary record

The Wavelet Transform was used to analyze the evolutionary record of planktic foraminifera to distinguish specific structure not previously resolvable. Both the speciation and extinction wavelets are characterized by a major singularity at the Cretaceous-Tertiary (K-T) boundary, when there was a total breakdown in the interconnectedness of ecosystems related to sharply reduced diversity following the Chicxulub impact event. The speciation wavelet is also characterized by an interval consisting of a hierarchical array of five orders of bifurcation, which are related to repeated iterative radiation of species from the Albian to Maastrichtian. These planktic foraminiferal extinction patterns were related to quasi-periodic orogenic cycles of the Cretaceous that, in turn, produced episodic mantle CO2-degassing, oceanic volcanism and anoxia, and sea level fluctutations. We hypothesize that the hierarchical structure observed is a reflection of this process in an otherwise stochastic system.