part_of part of part of preceded by simultaneous with in taxon occurrent gastrulation Eumetazoa embryo stage life cycle stage blastula stage gastrula stage OGES:000019 FBdv:00005317 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. trilaminar blastocyst stage WBls:0000010 OGES:000004 trilaminar stage EFO:0001296 BILS:0000109 XAO:1000005 BilaDO:0000008 trilaminar blastoderm stage trilaminar germ stage ZFS:0000047 trilaminar disk stage UBERON:0000109 blastocystis trilaminaris stage