We study economic natural selection in classical oligopoly settings. When u
nderlying pure strategies consist of a finite number of prices, convex mono
tonic dynamics always converge under a weak condition of the smallest price
in the support of the initial state that exceeds marginal cost. When under
lying pure strategies consist of a finite number of quantities, monotonic d
ynamics always converge under a specific condition to a quantity equal or s
imilar classical Cournot equilibrium.