Similarities:
* Aquatic Habitat: Both fish and sharks live in water, primarily in oceans and seas.
* Gills for Breathing: They both use gills to extract oxygen from the water.
* Streamlined Bodies: Their bodies are streamlined, helping them move efficiently through water.
* Fins for Movement: Both have fins, though their specific types and arrangements differ.
* Cold-Blooded: They are both ectothermic, meaning their body temperature is regulated by the surrounding environment.
* Reproduction: Both lay eggs (oviparous) or give birth to live young (viviparous) depending on the species.
* Sensory Systems: They share some advanced sensory systems, like lateral lines which detect vibrations in water.
Key Differences:
* Skeleton: Fish have a bony skeleton, while sharks have a cartilaginous skeleton (made of cartilage, a more flexible material).
* Scales: Fish scales are typically thin and flexible, while shark scales (called dermal denticles) are hard and tooth-like.
* Jaws: Sharks have jaws with multiple rows of teeth, often sharp and pointed, while fish have jaws with varying types of teeth.
* Swim Bladder: Fish typically have a swim bladder, a gas-filled sac that helps them control buoyancy. Sharks lack a swim bladder and rely on their large livers and fins for buoyancy.
Overall, fish and sharks are both aquatic animals with many common features, but their differences highlight their evolutionary adaptations for survival in their respective environments.