Fish

Classification Kingdom- ??? Phylum- Chordata Sub Phylum- Vertebrata Classes- Agnatha, Chondrichthyes, Osteichthyes

Class Agnatha Jawless fish: Lampreys, Hagfish

Examples of Agnathans Hagfish- Ocean scavengers, not much is known about them. Lamprey- fresh and salt water, they are parasitic and prey on other fish. Both have cartilagenous skeletons, sucker-like mouths, and a spinal column Neither have a vertebrae

A Sliming Hagfish

The Sea Lamprey

Class Chondricthyes Chondr – cartilage Ichthyes – fish Cartilaginous Fish: Shark, Ray, Skates, and Chimaeras

Class Chondrichthyes Skeletons made of cartilage Sharks are adapted for a predatory lifestyle: streamline body, teeth, stiff pectoral fins (built for speed). No operculum Most have live births (exception: skates) Placoid scales - (feels like sandpaper) Sting Rays and Skates - live in shallow water, have mouths located on the underside, are fairly docile, wide flat bodies and wing-like fins that are flexible.

Types of Chondrichthyes

Osteichthyes Bony Fish: Salmon, Trout, Tuna, etc. Over 20,000 different species

Types of Osteichthyes 1. Ray Finned: 2. Lobe Finned: Most fish are this type Fins are supported by bony, spiney structures called Rays. 2. Lobe Finned: Fins are long, fleshy, muscular, supported by bones that are not spiney. Thought to be ancestors of amphibians. An example is a lungfish

Fish Characteristics Gills Jaws (Most) Scales Vertebral Columns Paired Fins Single Loop Circulation Do not make certain amino acids

Different Dorsal Fins

Fish Respiration Water flows over gill surface as fish opens mouth and swims. Oxygen (O2) diffuses from the water into the blood. It removes 85% of the oxygen. Gills are made of thousands of gill filaments called lamellae. Gills are covered by the operculum which protects the gills and aids in pumping water.

Up Close and Personal

Fish Circulation Blood flows opposite from how the water flows over the gills; the friction helps remove the oxygen (85% efficient) Fish heart has 2 chambers: the atrium (receives O2–poor blood from the body) and the ventricle (sends blood out to the gills/body) Single loop circulation Blood flows into gills, picks up O2 while also getting rid of CO2, delivers O2–rich blood to the body to dump off O2, and returns O2–poor blood back the to the heart.

Fish Reproduction Most Fish reproduce sexually, and fertilize their eggs externally. Spawning is the process of fertilizing eggs via oviparous fertilization. Some reproduce internally and have live births. Baby fish are called fry.

Fish Adaptations Lateral Line System - used to detect vibrations, orient the fish in water, it is a line of cells running down the side of the fish. Operculum - gill cover, movement of operculum allows more water to be drawn in. Swim Bladder - a gas filled sac that helps the fish maintain buoyancy. It allows them to move to more shallow waters or dive to deeper waters. Sharks don’t have a swim bladder! Fins - Dorsal, Caudal, Pectoral, Pelvic, Anal.

Adaptations Swim Bladder Operculum Lateral Line and Fins Gills