Long Version:
The retention of the notochord in adult hagfish helps with their locomotion by providing structural support and allowing for flexion and extension of the body. The notochord is a flexible rod-like structure that runs along the length of the body and provides support for the muscles and other tissues. In hagfish, the notochord persists into adulthood and is surrounded by a sheath of muscle tissue.
The notochord allows hagfish to flex and extend their body in a lateral (side-to-side) motion, which is used for swimming and burrowing. When the hagfish extends its body, the notochord straightens and the muscles surrounding it contract, creating a wave-like motion that propels the hagfish forward. When the hagfish flexes its body, the notochord bends and the muscles relax, allowing the hagfish to move in a different direction or to stop swimming.
Overall, the retention of the notochord in adult hagfish helps with their locomotion by providing structural support and allowing for flexion and extension of the body. This enables hagfish to move effectively in their aquatic environment and to perform a variety of behaviors, such as swimming, burrowing, and capturing prey.
Shorter Version:
The retention of the notochord in adult hagfish helps with their locomotion by providing structural support and allowing for body flexion and extension. This enables hagfish to move effectively in their aquatic environment and to perform a variety of behaviors.