Question

what are monoblastic, diploblastic and triplo blastic organisms?

Answer 1

Diploblastic:

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

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

3. Coelom is absent, e.g. Hydra (coelenterates), 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. platy-helminthes, annelids, arthropods, mollusks, echinodermsand choradates.

Answer 2

Classification of animals can be made on the basis of the number of germ layers:

Animals that have two prominent germ/embryonic layers- Ectoderm( external layer) and Endoderm( internal layer)and one indifferentiated layer in between the two layers are called Diploblastic animals.

Example: Coelenterates.

Animals that have all the three germ layers present in them- Ectoderm, Mesoderm( middle layer) and Endoderm are called Triploblastic animals.

Example: Platyhelminthes.

Monoblasts are cells that are present in bone marrow and mature into monocytes and ultimately to macrophages.