Thais Vasconcelos, Brian O'Meara, Jeremy Beaulieu

In 1974, G. Ledyard Stebbins provided a metaphor illustrating how spatial gradients of biodiversity observed today are byproducts of the way environment–population interactions drive species diversification through time. We revisit the narrative behind Stebbins’ “cradles” and “museums” of biodiversity to debate two points. First, the usual “high speciation” vs. “low extinction” and “tropical” vs. “temperate” dichotomies are oversimplifications of the original metaphor and may obscure how gradients of diversity are formed. Second, the way in which we use modern gradients of biodiversity to interpret the potential historical processes that generated them are often still biased by the reasons that motivated Stebbins to propose his original metaphor. Specifically, the field has not yet abandoned the idea that species-rich areas and “basal lineages” indicate centers of origin, nor has it fully appreciated the role of traits as regulators of environment–population dynamics. We acknowledge the popularity of “cradles” and “museums” in the literature and that terminologies can evolve with the requirements of the field. However, we also argue that “cradles” and “museums” have outlived their utility in studies of biogeography and macroevolution and should be replaced by discussions of actual processes at play.