SEAN B. CARROLL: “A long-standing issue in evolutionary biology is whether the processes observable in extant populations and species (microevolution) are sufficient to account for the larger-scale changes evident over longer periods of life’s history (macroevolution). Outsiders to this rich literature may be surprised that there is no consensus on this issue, and that strong viewpoints are held at both ends of the spectrum, with many undecided.”

— Sean B. Carroll, genetics professor, Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin-Madison (“The big picture,” Nature 409:669, 2001).