Question

Distinguish between diploblastic and triploblastic organisation

Answer 1

Diploblastic:
Animals in which the embryo have two embryonic tissue layers or germ layers i.e. ectoderm and endoderm are termed as diploblastic.
Coelom is absent.

Examples: Sponges, coelenterates and cnidarians  

Triploblastic:
Animals in which the embryo have three embryonic tissue layers or germ layers i.e. ectoderm, mesoderm and endoderm are termed as triploblastic.
Coelom is present.

Examples: Mammals, birds, reptiles

Answer 2

Diploblastic and triploblastic refer to two different types of blastula stages. The primary layer of cells, formed during the embryogenesis is referred to as the germ layer. In vertebrates, three germ layers can be generally identified in the gastrula; they are endoderm, mesoderm and the ectoderm. Animals with a more complex structure than a sponge (eumetazoans) however produce two or three germ layers. Radially symmetric animals are diploblastic. They produce only two germ layers: endoderm and the ectoderm. Bilaterally symmetric animals are triploblastic. They produce the three germ layers: endoderm, ectoderm and the mesoderm. The key difference between diploblastic and triploblastic animals is that diploblastic animals produce two germ layers excluding mesoderm and triploblastic animals produce all three germ layers.