Chordates and Marine Fish Overview

A group of animals that possess a dorsal hollow nerve cord, notochord, pharyngeal gill slits, endostyle or thyroid, and a post-anal tail at some point in their life cycle.

A subphylum within Chordata characterized by a gelatinous outer covering called a tunic, filter feeding through incurrent and excurrent siphons, and a sessile lifestyle. Only their larvae possess all chordate features.

A subphylum within Chordata that retains all chordate characteristics throughout its life. They are slender, fish-like creatures that filter feed and are primarily found in marine environments.

A group of chordates with a backbone (dorsal row of hollow vertebrae), bilateral symmetry, and an endoskeleton. They include fish, reptiles, birds, and mammals.

A group of jawless fish that includes lampreys and hagfish. They are characterized by an eel-like body, median fins, and a lack of jaws.

A class of bony fish with calcium-based skeletons, overlapping scales, an operculum protecting their gills, and a swim bladder for buoyancy. They are found in both freshwater and saltwater environments.

A class of fish with cartilaginous skeletons, lacking bones and having a more primitive jaw structure. Examples include sharks, rays, and skates.

A sensory system in fish that detects vibrations and pressure changes in the water, aiding in their ability to navigate and find prey.

Oxygen diffuses from the water into the blood, because the blood has a lower oxygen concentration than the water. This is achieved by having the water and blood flow in opposite directions, maintaining a constant concentration gradient.

A specialized network of blood vessels that helps maintain the concentration gradient for gas exchange in fish gills. This network of vessels allows for efficient transfer of oxygen from the water to the blood.

The protein in red blood cells that binds and transports oxygen throughout the body.

The protein in muscle tissue that stores oxygen, allowing muscles to work for longer periods without relying solely on blood oxygen.

Fish need to maintain a balance between the salt concentration in their body and the environment. Bony fish achieve this by filtering out excess salt through their kidneys and excreting small amounts of concentrated urine.

The area that a fish defends against other individuals to protect its resources, such as food or mates.

A group of fish that travel together for protection and increased swimming efficiency.

Regular movements of fish from one location to another, often for breeding or feeding.

Cartilaginous fish like sharks and rays; have a skeleton made of cartilage, not bone.

Specialized scales found on cartilaginous fish, designed for protection and hydrodynamic efficiency.

Openings on the side of the head in some sharks and rays, used for respiration.

Fins that are wider than they are long, like wings, found in rays and skates.

The 'S-shaped' motion used by fish to move through water, driven by muscle contractions.

Specialized sensory organs in cartilaginous fish that detect electrical fields, helping them locate prey.

Camouflage that helps an animal blend in with its surroundings, making it difficult to see.

A type of camouflage that uses color patterns to break up an animal's outline, making it harder to see.

A type of coloration where the dorsal (top) side of the fish is darker than the ventral (bottom) side. This helps camouflage the fish against the background. Examples include tuna and great white sharks.

A type of coloration where the fish mimics another animal or object to avoid predators or attract prey. Examples include stonefish, which resemble rocks, and false cleaner wrasses, which mimic real cleaner wrasses.

A type of specialized skin cell that contains pigments like yellow, red, orange, or black. These cells are irregularly shaped and branch out. They give fish their vibrant colors.

A type of specialized skin cell that contains guanine, a substance that reflects light. These cells make the fish appear iridescent, creating a shimmering effect. This is a structural color, meaning it's not from pigments, but from how light interacts with the cell's structure.

A type of fish that actively hunts and ambushes prey. Examples include barracuda, piranhas, and moray eels.

A type of fish that feeds on algae, marine debris, or other plant material. Examples include many reef fish.

A type of fish that feeds on decaying organic matter, like carcasses. Examples include remoras and eels.