  We derived a new speed limit in population dynamics, which is a fundamental
limit on the evolutionary rate. By splitting the contributions of selection and
mutation to the evolutionary rate, we obtained the new bound on the speed of
arbitrary observables, named the selection bound, that can be tighter than the
conventional Cram\'{e}r--Rao bound. Remarkably, the selection bound can be much
tighter if the contribution of selection is more dominant than that of
mutation. This tightness can be geometrically characterized by the correlation
between the observable of interest and the growth rate. We also numerically
illustrate the effectiveness of the selection bound in the transient dynamics
of evolutionary processes and discuss how to test our speed limit
experimentally.
