Exoskeleton and Endoskeleton

An exoskeleton is a hard, external covering that provides support and protection for an animal's body. It is typically made of chitin, a tough protein, and covers the entire body of the organism. In contrast, an endoskeleton is an internal skeleton made of bones or cartilage that provides structural support and protection for the body.

Cockroach Locomotion

- Cockroaches have an exoskeleton made of chitin.
- They move using their six legs, which are attached to their thorax.
- Cockroaches can move quickly in a variety of directions, using their legs for both walking and climbing.

Fish Locomotion

- Fish have an endoskeleton made of bones or cartilage.
- They move by swishing their tail from side to side, propelling themselves forward.
- Some fish also use their fins for steering and stability in the water.

Earthworm Locomotion

- Earthworms do not have a skeleton but instead have a hydrostatic skeleton made of fluid-filled compartments.
- They move by contracting and relaxing their circular and longitudinal muscles, allowing them to push themselves forward.
- Earthworms also use tiny bristles called setae on their body segments to grip the soil as they move.

Bird Locomotion

- Birds have an endoskeleton made of lightweight bones.
- They move by using their wings to generate lift and thrust, allowing them to fly.
- Birds also use their legs and feet for walking, hopping, or perching on branches.