Climate has long been recognized as a deterministic factor in shaping species ranges and assemblages, but there is a growing appreciation for the role of ecological interactions in modulating how species respond to climate change. Given this, it's troubling that we know so little about 1) the degree to which biotic interactions shape contemporary distribution patterns, 2) how interactions themselves are likely to change due to climate change or extinction, and 3) whether those interactions will help or hinder a species' ability to track its climatic niche through space and time. In this talk, I'll discuss three case studies from the recent geologic record that shed light on the causes of climate-driven extinction, and the impacts of extinction on plant community dynamics and distributions at the macroecological scale.