derives from/develops from
blastula
gastrula
An early metazoan embryo in which the ectoderm, mesoderm, and endoderm are established either by invagination of the blastula (as in fish and amphibians) to form a multilayered cellular cup with a blastopore opening into the archenteron or by differentiation of the blastodisc (as in reptiles, birds, and mammals) and inward cellular migration.
BTO:0001403
BrendaTissueOBO
blastodisc