part of preceded by simultaneous with in taxon occurrent gastrulation Eumetazoa embryo stage life cycle stage blastula stage gastrula stage OGES:000019 EFO:0001296 FBdv:00005317 BILS:0000109 XAO:1000005 A stage defined by complex and coordinated series of cellular movements that occurs at the end of cleavage during embryonic development of most animals. The details of gastrulation vary from species to species, but usually result in the formation of the three primary germ layers, ectoderm, mesoderm and endoderm. BilaDO:0000008 trilaminar blastoderm stage trilaminar germ stage trilaminar blastocyst stage ZFS:0000047 trilaminar disk stage WBls:0000010 OGES:000004 trilaminar stage blastocystis trilaminaris stage