Question

Explain diploblastic and triploblastic organisation.

Answer 1

Depending on the primary germ layers present in the blastula stage of organisms, they can be categorized mainly into two groups; diploblastic and triploblastic.

Diploblastic:

1. Body wall develops from two embryonic germ layers- ectoderm and endoderm and persists as such in adults.

2. Non-cellular, gelatinous mesogloea is present in between ectoderm and endoderm.

3. Coelom is absent, e.g. Hydra (coelenterates), and sponges (Porifera).

Triploblastic:

1. Body develops from 3 germ layers- ectoderm, mesoderm, and endoderms.

2. Mesogloea is absent and mesoderm is present.

3. Coelom is present, e.g. platyhelminths, annelids, arthropods, mollusks, echinoderms, and chordates.