Fish

Fish are Vertebrates All fish have a backbone and belong to the phylum Chordata Backbone protects the spinal chord and support the rest of the body Fish have a well developed head protected by a skull Fish are made of cartilage, a tough flexible materials or bones Fish have been around for 500 million years and are considered to be the first vertebrates

Staying Warm Mammals and birds have a stable body temperature. They are known as endotherms and are warm blooded Fish do not control their body temperature and are known as ectotherms. Their body temperatures depends on the temperature of their environment Fish are considered cold blooded

Characterisitics Strong muscle network for quickness and power Fins to help steer, stop, and balance Scales protect the fish and help them move through the water more easily A brain and the senses of sight, hearing and smell A lateral line that helps a fish detect nearby vibrations in the water

Gills – Allow a fish to breathe by removing oxygen from the water Use fertilization both external and internal for reproduction. ( female eggs and male sperm)

Classes of Fish Jawless fish – Eel like fish that either eat dead fishes on the ocean floor or suck blood from other animals flesh Examples are Hagfish or Lampreys

Cartilaginous Fish do not have any bones Defined jaw, strong swimmers and expert predators Must keep swimming to stay afloat and to move water over their gills Examples would be sharks

Bony Fish are typical fish. 95% of all fish belong in this class Have a skeleton with bones They can rest in one place because of an organ called a swim bladder that keeps them afloat Examples would be goldfish, tuna, trout, bass