Abstract

Life on Earth descends from a common ancestor. However, it is likely that there are other instances of life in the universe. If so, each abiogenesis event will have given rise to an independently originated life clade, of which Earth-life is an example. In this paper, I argue that the set of all IOLCs in the universe forms a Darwinian population subject to natural selection, with more widely dispersed IOLCs being less likely to face extinction. As a result, we should expect that, over time, more planets will become inhabited by fewer, more successful IOLCs.