Beyond the Fast-Slow Continuum of Life Histories

Life history theory is key to understanding Earth’s diverse life forms. Indeed, schedules of survival, development, and reproduction are the filters through which natural selection acts on species’ heritable traits to shape fitness. Prevailing wisdom places species’ life history strategies along a fast-slow axis of variation. Challenges to the unicity of this axis are increasingly frequent, given proliferation of life history databases and availability of sophisticated multivariate statistical techniques. However, these empirical approaches often lack concrete theoretical or hypothetical foundations. We advocate for using standardised traits, targeting data gaps and overcoming focus on taxonomic siloes, to facilitate a hyopthesis-driven approach in future examination of drivers of life history variation across the whole Tree of Life.