Goals Not Yet Accomplished
The integrated approach to understanding the Earth-life system exemplified by scientific ocean drilling has resulted in a spectacular understanding of some of the largest biotic changes the planet has seen in the past 200 myr. Although some initial discoveries, such as the K-T impact, occurred on land, deeper understanding was achieved by the contextual approach provided by sediments preserved in the ocean basins. However, a number of scientific ocean drilling-related goals for the Earth-life system have yet to be realized. For example, very little new core-based progress has occurred in understanding the roles of LIPs in biotic change or the overall structure of the Chixulub crater. Scientific ocean drilling may also continue to contribute to understanding the processes that link climatic and evolutionary events in hominin evolution. Finally, the effects of the evolution of new life forms and new physiological modalities on biogeochemical cycles has not been examined in scientific ocean drilling studies; organisms and their physiology are a first-order control on processes such as oxygenation, terrestrialization, agronomic revolution, human culture, and technology.