There are only a few vertebrates that have no jaws, such as lampreys and hagfish. Jaws evolved from gill arches in fish and provided benefits like being able to hold food so it couldn't escape from the stomach. Paired fins also evolved around the same time, and it would have been difficult to swim without front fins. Both lampreys and hagfish are jawless fish, with lampreys having an eel-like body structure and hagfish having eyes beneath their skin and no vertebrae.
There are only a few vertebrates that have no jaws, such as lampreys and hagfish. Jaws evolved from gill arches in fish and provided benefits like being able to hold food so it couldn't escape from the stomach. Paired fins also evolved around the same time, and it would have been difficult to swim without front fins. Both lampreys and hagfish are jawless fish, with lampreys having an eel-like body structure and hagfish having eyes beneath their skin and no vertebrae.