develops_from develops from existence starts and ends during blastula stage blastula BILA:0000059 BTO:0000128 GAID:1294 MESH:A16.254.270.274 OGEM:000006 OpenCyc:Mx4rEetFnKP2EdqAAAACs4vPlg Organism at the blastula stage - an early stage of embryonic development in animals. It is produced by cleavage of a fertilized ovum and consists of a spherical layer of around 128 cells surrounding a central fluid-filled cavity called the blastocoel. The blastula follows the morula and precedes the gastrula in the developmental sequence. TODO - check relationship with epiblast. Note in FMA this is not a subclass of embryo, but in uberon embryo is the whole organism from zygote onwards and thus includes the blastula UBERON:0000307 UBERON:0007011 blastosphere blastula embryo uberon multi-cellular organism embryo cleaving embryo