Generic criticality in a model of evolution

Using Monte Carlo simulations, we show that for a certain model of biologic al evolution, which is driven by nonextremal dynamics, active and absorbing phases are separated by a critical phase. In this phase both the density o f active sites rho(t) and the survival probability of spreading P(t) decay as t(-delta), where delta similar to 0.5. At the critical point that separa tes the active and critical phases delta similar to 0.29, which suggests th at this paint belongs to the so-called parity-conserving universality class . Such a classification is also supported by finite-size analysis. The mode l has infinitely many absorbing states and, except for a single point, has no apparent conservation law.