The ability of organisms to synthesize skeletons and functional biomineral structures is one of the most remarkable events in the timeline of mineral evolution. The relatively abrupt rise of such forms in the fossil record marks the beginning of a new type of chemistry whereby biology develops a playbook of mineralization processes whose strategies scientists are only beginning to decipher. The first outlines of an impressive picture are emerging, in which the biochemical machinery and sequence of instructions that pass forward to subsequent generations are being defined. Yet, skeletons are anything but static in the transfer. The fossil record shows the dynamic responses of skeletal structures to shifts in environmental conditions over geologic time.