Diploblasts

Definition

Diploblasts are animals that develop from two primary germ layers: the ectoderm and the endoderm. They lack a mesoderm, which is present in more complex organisms called triploblasts.

5 Must Know Facts For Your Next Test

1. Diploblasts include phyla such as Cnidaria (jellyfish, corals) and Ctenophora (comb jellies).
2. They have radial symmetry, meaning their body plan is arranged around a central axis.
3. The ectoderm forms the outer layer of cells, while the endoderm forms the inner lining of the gut.
4. Diploblastic animals do not possess true muscles derived from mesoderm; instead, they have simple muscle-like cells.
5. They typically exhibit simple tissue organization and lack complex organs found in triploblastic organisms.

Related terms

Triploblasts: Animals that develop from three primary germ layers: ectoderm, mesoderm, and endoderm.

Germ Layers: Primary layers of cells in embryonic development that give rise to all tissues and organs.

Radial Symmetry: A body plan in which any longitudinal cut through the organism's central axis results in identical halves.