Fish

Vocabulary list

fins – a thin, triangular part on a fish, which helps it to swim

scale - any of the thin plates of hard material that cover the skin of many fish and reptiles

gill - a respiratory organ found in many aquatic organisms

jaw - either of the two bones inside a mouth that contain teeth

pharynx - the soft part at the top of the throat that connects the mouth and nose

 

Fishes are animals with backbones that live in water. They usually have paired fins, scales, and gills.

Fishes were the first vertebrates to evolve. The evolution of jaws and paired fins were the most important development in fish evolution. Jaws improved defense and expanded food choices. Paired fins gave more control of body movement.

Most fishes breathe with gills. Gills have many tiny blood vessels. This provides a large surface area for oxygen and carbon to be exchanged. Most fishes breathe by pulling water through the mouth and pumping it over the gills and out through openings in the sides of the pharynx.

Most fishes get rid of wastes as ammonia. Some wastes pass through the gills into the water. Other wastes are removed from the blood by the kidneys. Kidneys also help fishes control the amount of water in their bodies.

 

Answer the questions:

Are fish vertebrate animals?

What external organs are familiar for all fish?

What were the most important organs in fish evolution?

Do fish breathe air of water?

How do fish get rid of wastes?