We synthesize organization learning theory and organizational ecology to predict systematic patterns in the founding and growth of organizations over time. Our central argument is that competition triggers organizational learning, which in turn intensifies competition that again triggers an adaptive response. We model this self-exciting dynamic--sometimes referred to as the 'Red Queen' in general evolutionary theory--to explain organizational founding and growth rates among the thousands of retail banks that have operated in Illinois at any time from 1900--1993. We find strong evidence that Red Queen evolution led some organizations to grow quickly and to place strong competitive pressure on rivals. Red Queen evolution also helped establish barriers to entry. However, this same evolutionary process appears to make organizations more susceptible to 'competency traps', ultimately slowing their growth rates and inviting new market entry. Organizations confronted by a widely varying distribution of competitors grow more slowly and are more likely to face new entrants. Overall, the results suggest that processes of organizational creation and growth emerge from ecologies of learning organizations. More generally, we discuss the use of ecological theory and models to study the empirical consequences of organizational learning. Сopyright 2002, Oxford University Press.