SEPKOSKI, J. JOHN JR. (1948-1999): ESTABLISHING THE FRAMEWORK FOR MODERN PALEOBIOLOGICAL ANALYSIS

As is true for much of the geosciences, paleontological data are sparse and extend over vast timescales. Each datum, the occurrence of a taxon at a specific place, time, and environment is hard won, not to mention the added tasks of inferring the function, ecology and evolutionary relationships of the taxa. Jack Sepkoski made many seminal contributions to our understanding of the history of life, but his pre-eminent achievements centered on the brute force compilation, analysis, and biological interpretation of the times of first and last appearances of ALL marine animal taxa. This was accomplished before the internet, e-mail, and electronic publishing. Jack began at coarse taxonomic levels, the classes and orders, then developed a family-level compendium, and then examined the entire literature once again, surveying every issue of every journal to compile a genus-level compendium, amassing stratigraphic ranges for some 31,500 genera. These databases revolutionized our understanding of the history of life at a global scale. Jack used them: to help establish the basic pattern of Phanerozoic diversity change in which he famously demarcated three evolutionary faunas and sought to model and diagnose the causes of the transitions from one fauna to the next; to distinguish between background and mass extinctions; to recognize an environmental, onshore-offshore overprint on diversification; and to diagnose mass-extinction periodicity. He was tireless in his refinement of the data and in seeking the advice of taxonomic and stratigraphic experts. He was remarkably generous with his compendia, giving them on a floppy disk to anyone who asked – probably the first example of paleontological digital open access. His synoptic figures still dominate the literature and presentations at professional meetings, as well as all the major textbooks in paleontology, evolutionary biology, and even biogeography. His data and interpretations have been at the heart of huge array of fundamental advances in paleobiology. Jack left us all too young, passing away at the age of 50. But his work has inspired the next generation of paleontological databases, including the Paleobiology Database, and the questions that can be asked of them. His ideas and contributions remain central to many contemporary macroevolutionary questions.