The purpose of the backbone in vertebrates is to provide structural support and protection for the spinal cord. Comprised of individual vertebrae, the backbone enables flexibility and movement while maintaining the body's shape. It serves as an important attachment point for muscles and helps to distribute weight throughout the body. Additionally, the backbone plays a key role in locomotion and supports the overall function of the nervous system. Therefore, this structure is essential for both physical stability and the coordination of bodily movements in vertebrates.