The interplay of physical and biotic factors in macroevolution

The study of macroevolution, here defined simply as evolution above the species level, has seen a growing appreciation of the role of physical factors in shaping large-scale evolutionary patterns. Many of the major biotic turnovers, extinctions, and radiations that had once been attributed to direct competitive replacements or adaptive breakthroughs are now seen as physically mediated. Asteroid impacts, abrupt changes in ocean circulation and atmospheric chemistry, and a host of other physical perturbations and secular trends have been emerging as plausible hypotheses for major biotic patterns in the history of life. Now that the range of potential hypotheses has expanded more fully into the physical