WHAT WE KNOW, THINK WE KNOW, AND DON'T YET KNOW ABOUT ECOLOGICAL DIVERSITY DURING THE PHANEROZOIC (Invited Presentation)

Understanding how ancient life functioned ecologically remains a critical goal for paleontology, with consequences for understanding extinction selectivity, ecological interactions, and macroevolution. We know much about this history already: the evidence is overwhelming that larger and more mobile burrowing and predatory animals have evolved through time. And it is true that intervals with greater taxonomic diversity also ought to be times of greater ecological diversity.

What is less clear is how robust these patterns are (i.e., are they driven trends or passive side-effects of other dynamics?), and what ecological and evolutionary processes have caused them. The nascent discipline of functional ecology, with its quantitative focus on testing novel ecological hypotheses, offers exciting opportunities to leverage our paleontological knowledge with a vibrant ecological discipline.

In this presentation, I argue that despite much success, we have much to learn, and now is the ideal time to capitalize on these developments to test critical but largely unanswered questions. For example, are bivalves taxonomically rich because they are inherently ecologically versatile, or are they ecologically rich as a side-effect of their fast rate of evolution? Within individual lineages, do predators have greater extinction risk than suspension-feeders? How does body size co-vary with other life-habit dimensions (such as feeding, motility, or ability to live in certain habitats)? Are lineages occupying certain regions of ecospace more prone or resistant to background or mass extinctions? Are taxonomically rich local assemblages also ecologically more diverse?

These and many other important questions are poorly studied, in large part because the necessary data on life habits needed to test them have been previously insufficiently available. I will share ongoing efforts to develop such a database and suggest possible answers for some of these questions. Along the way, I will summarize areas of active research in functional ecology, discuss best practices in building statistically powerful ecospaces, and evaluate analytical methods—largely adopted from functional ecology—that allow us to capitalize on paleontology's vast knowledge of ancient life habits to answer these critical questions.