Feeding:
* Parasitic lifestyle (lampreys): Lampreys have a specialized mouth with sharp teeth and a tongue covered in rasping hooks. This allows them to attach to and feed on the blood and flesh of other fish.
* Scavenging (hagfish): Hagfish are scavengers and feed on dead or dying fish and other marine animals. Their mouths are equipped with numerous sharp teeth and a tongue with a pair of barbs that they use to tear at flesh.
* Mucus production: Both lampreys and hagfish produce large amounts of slime as a defense mechanism. This mucus can clog the gills of predators and deter them from attacking.
Locomotion:
* Cartilaginous skeleton: Their skeletons are made of cartilage, which is lighter and more flexible than bone, allowing them to be agile and maneuverable.
* Undulating body: They have a long, slender body with a series of muscle segments that allow them to swim in an undulating, snake-like motion.
* Lack of paired fins: The absence of paired fins like those found in bony fish means they rely on their body undulation for movement.
Other Adaptations:
* Nocturnal behavior: Many jawless fish are more active at night, which may help them avoid predators.
* Burrowing ability: Hagfish can burrow into sediment, providing them with shelter and a way to ambush prey.
* Sensory organs: They have well-developed sensory organs, including a lateral line system for detecting vibrations and a keen sense of smell for locating prey.
Evolutionary Significance:
Jawless fish represent some of the earliest vertebrates to evolve on Earth. Their unique adaptations showcase how early life forms adapted to diverse environments and developed survival strategies that paved the way for later evolution of jawed vertebrates.
It's important to note that the adaptations mentioned above are not exhaustive, and different species of jawless fish have developed additional, specialized adaptations to survive in their specific environments.