Triploblasts

Definition

Triploblasts are animals whose embryos develop three primary germ layers: the ectoderm, mesoderm, and endoderm. These layers give rise to all the tissues and organs of the organism.

5 Must Know Facts For Your Next Test

1. Triploblasts include most animals except sponges and cnidarians.
2. The three germ layers in triploblasts form during the gastrulation phase of embryonic development.
3. The mesoderm in triploblasts gives rise to muscles, bones, and the circulatory system.
4. Triploblastic animals can be further classified into protostomes and deuterostomes based on their developmental patterns.
5. Examples of triploblastic animals include humans, insects, and fish.

Review Questions

• What are the three primary germ layers in triploblasts?
• Name two major groups that exclude triploblastic animals.
• How do protostomes and deuterostomes differ among triploblasts?

Related terms

Ectoderm: The outermost germ layer that forms structures such as skin and nervous tissue.

Mesoderm: The middle germ layer that develops into muscles, bones, and the circulatory system.

Endoderm: The innermost germ layer that forms internal structures like the digestive tract and lungs.