‘‘Biological Emergences: Evolution by Natural Experiment’’—seeks to reestablish

pages. Does adaptability evolve in concert with adaptation or independently of it, emerging as a by-product of organismal existence regardless of the fitness consequences per se? Answering this question would resolve a number of paradoxes in evolutionary biology. In genomics, it would explain the evolution of networks that combine evolvability on long evolutionary scales with robustness during development, as well as the remarkable redundancy and dispensability of gene effects in sequenced genomes. In physiology and biochemistry, it would shed light on puzzling evolutionary transitions in homeostasis—a trait that should be resistant to all changes, and address the contrast between evolutionary stasis and rapid within-generation physiological and biochemical adjustments of organisms to their environments. And in behavioral biology, it would resolve the conflicting role of behavioral plasticity as ‘‘inhibitor’ ’ versus ‘‘driver’ ’ of evolutionary change. The reason for such importance is that the link between adaptation and adaptability enables us to envision the connection between the maintenance of adaptation an