Ecdysozoans

Question

Ecdysozoans

Quizplus · Accepted Answer

Ecdysozoans are a diverse group of animals that share a common characteristic of having a cuticle, which is a tough, protective outer layer that is molted or shed periodically as the animal grows. This includes organisms such as nematodes, arthropods, and tardigrades. While some ecdysozoans, such as arthropods, do have a thick, hard exoskeleton composed of protein and chitin, not all members of the group share this feature, making option B and C incorrect. Similarly, not all ecdysozoans have jointed appendages, eliminating option E. Finally, ecdysozoans are not a polyphyletic group, as they are believed to share a common ancestor and are therefore considered a monophyletic group.