Let me share with you a comparison between Exoskeleton and Endoskeleton.
| Aspect | Exoskeleton | Endoskeleton |
| Location | Present outside, covering the body of the organism. | Present inside the body of the organism. |
| Composition | · Chitin (in arthropods) · Calcium carbonate (in some mollusks) · Proteins | · Composed of bones or cartilage in vertebrates. |
| Growth | Inflexible and must be shed or molted for the organism to grow. | Capable of growing with the organism. |
| Protection | Provides a rigid external barrier protecting against physical injuries and predators. | Provides internal support and protection for vital organs and soft tissues. |
| Movement | Muscles are attached to the inner surface and contractions cause movement by moving the exoskeleton segments. | Muscles are attached to the skeleton and contractions cause movement by pulling on the bones. |
| Flexibility | Limited flexibility due to its rigid structure. | Greater flexibility, allowing a wider range of movements. |
| Weight | Generally lighter compared to endoskeletons. | Can be heavier, especially in larger animals |
| Examples | · Arthropods e.g. insects, crustaceans and arachnids · Some mollusks e.g., snails with shells | · Vertebrates · Some invertebrates e.g., echinoderms |