Bony Fish

The Class Osteichthyes: 

• Lobe-finned fish
  • Known only as fossils until 1938.
  • The Coelacanth has paddle-like fins with a fleshy base.
  • Living species found in Africa
• Lungfish
  • Have lungs, internal organs for gas exchange between air and the blood.
  • Only a few species are known.
• Ray-finned fish
  • Fins are supported by stiff rays and/or bony spines.
  • All other bony fish, both freshwater and saltwater, are in this group.

Fish Body Parts

Dorsal Fin: top, keeps body straight up and down
Caudal Fin: "tail fin"; provides propulsion
Anal Fin: located in front of anus; keeps body straight up and down
Pelvic Fin: paired fins; used to steer left and right and backward
Pectoral Fin: paired fins; moves fish up and down
Adipose: found on catfish and trout; fleshy fin between dorsal and caudal fins
Lateral Line: A row of scales with sensory depressions down each side of the fish.
                   This system detects vibrations in the water.
Chromatophores: structures containing pigment to provide color patterns.

• Most fish have large eyes to help gather light in dim surroundings.
• In bright surroundings, this causes fish to seek shadows.
  

Gills:  external tissue rich with blood vessels to exchange gases with the water.

Operculum - a hard plate on either side of the head that protects the gills and opens at the rear to allow water to flow through the mouth and over the gills.

Swim bladder:

A thin-walled sac along the top of the abdominal cavity containing a mixture of oxygen, carbon dioxide, and nitrogen obtained from the bloodstream.

The swim bladder usually produces neutral buoyancy, but some fish are able to adjust their buoyancy by slightly changing the amount of gas in the swim bladder.

Almost all fish have a swim bladder. Those without one, like sharks and freshwater darters, sink if they stop moving their fins.

Yes, fish can talk! 

The circulatory system of simple vertebrates:

Atrium - the collecting chamber. upper
Ventricle - the pumping chamber. lower
Arteries - thick-walled blood vessels that carry blood under high pressure away from the heart.
Veins - thin-walled blood vessels that carry blood under low pressure toward the heart.
Capillaries - small blood vessels that connect arteries and veins.

Olfactory lobes - respond to smell.
Cerebrum - respond to smell and other sensory information.

Optic lobes - largest lobes - process information from the visual, auditory, and lateral line systems. This part of the brain is also responsible for turning the animal's body toward or away from a stimulus.

Cerebellum - muscle coordination.
Medulla oblongata - regulates internal organs.

Cranial nerves - connect major sense organs directly to the brain.
Spinal nerves - connect internal organs and muscles to the spinal cord.

Spawning: the external fertilization of fish eggs.

• In many Oklahoma fish species, the male uses his fins to make a depression to use as a "nest".
• He then tries to guide a female to the nest to release her eggs.
• He swims over the eggs and releases his milt, a fuid containing the sperm. This "external fertilization" is inefficient, but having the eggs in the depression helps.
• In most cases, the female will guard the nest until the eggs hatch. After that, the hatchlings are on their own.