Evolving life-history traits promote biodiversity via eco-evolutionary feedback mechanisms

To what extent is biodiversity shaped by environmental conditions, and to what extent is it the result of self-organization? Both natural processes and organismal properties may contribute to promoting diversity. Here, we show that one such process, namely natural selection, and an organismal property, namely life history, interact in a feedback mechanism that promotes the emergence of diversity. We illustrate how this mechanism operates using various models of ecological diversification driven by intraspecific resource competition, in which both a niche trait that determines resource use and a life history trait can evolve. We find that natural selection acting on life history traits leads to increased competition, which, in the presence of ecological opportunity, facilitates niche diversification. As a consequence, the environmental conditions for diversification are more restrictive in the absence of life history evolution than in its presence. Our findings indicate a strong influence of life history evolution on ecological processes that in turn shape the origin of biodiversity. Our results call for a better integration of life history evolution and niche diversification in both theoretical and empirical realms.