Exoskeletons vs. Endoskeletons

Exoskeletons vs. Endoskeletons

• Exoskeleton: An external skeletal system; the skeleton is on the outside of the body. Examples include crabs, insects, lobsters.
• Endoskeleton: An internal skeletal system; the skeleton is inside the body. Examples include humans, dolphins, birds.

Skeletal Systems: Similarities

• Protection: Both exoskeletons and endoskeletons protect the body and internal organs.
• Movement: Both help the body move.
• Framework: Both provide a framework to give the body shape.

Exoskeleton Details

• Materials: Made of chitin and calcium carbonate.
• Chitin: Strong but flexible, allowing for movement.
• Calcium Carbonate: Provides hardness to the exoskeleton.
• Invertebrates: Most animals with exoskeletons are invertebrates (lacking a backbone).
• Insect Prevalence: Insects are the largest group with exoskeletons.
• Other Examples: Crabs, lobsters, shrimp, snails, and spiders also have exoskeletons.
• Growth Limitation: Exoskeletons do not grow with the animal. Some animals shed their exoskeleton (molt) to grow.

Endoskeleton Details

• Materials: Made of bones and cartilage (a type of hard tissue).
• Growth: Endoskeletons grow with the animal.
• Vertebrates: Animals with endoskeletons are vertebrates (have a backbone).
• Human Bone Count: Adult humans have more than 200 bones.
• Other Examples: Dolphins, whales, fish, and birds.
• Axial Skeleton: Part of the endoskeleton; protects vital organs like the brain and lungs. In humans, this includes the skull, backbone, and ribcage.
• Appendicular Skeleton: Part of the endoskeleton; provides shape and support for areas such as the legs and arms. In humans, this includes shoulder, arm, leg and pelvic bones.