Abstract

The fossil record of echinoids indicates that a nonplanktotrophic developmental pattern first evolved, and was independently adopted, in nine clades immediately prior to the Cretaceous-Tertiary boundary. These near-synchronous shifts in developmental mode, which occurred over a broad taxonomic and latitudinal range, point to increasing seasonality as a forcing factor and provide the first clear evidence that environmental change on a global scale can drive synchronized shifts in life-history strategy.

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