Ichthyology • The study of fish.
Classification of Fish • Kingdom Animalia • Phylum Chordata • Subphylum Vertebrata
3 Classes of Fish • Class Agnatha • Class Chondrichthyes • Class Ostyeichthyes
Class Agnatha • Jawless fish • Examples: lamprey and hagfish
Class Chondrichthyes • Cartilage fish • Examples: Sharks and Rays
Jabber Jaws Shark
Class Ostyeichthyes • Bony fish • Examples: Salmon, Carp, Catfish
Characteristics of Fish • Gills • Backbone (vertebrae) • Paired fins • Single loop circulation
Fish Respiration • Water flows over gills as the fish swims-this water is flowing in the opposite direction of the flow of blood (countercurrent flow). • Oxygen diffuses from the water and into the blood.
Fish Respiration • Gills are made of thousands of gill filaments.
Fish Respiration • When a fish opens its mouth, it “swallows” water, water passes over the gills and then out the gill slits, which are covered by the fish’s operculum. • You can see the operculum opening and closing.
Fish Circulation • The fish heart is a single loop circulation which has 2 chambers. • Blood flows into the gills, picks up oxygen, goes to the body and then returns to the heart.
Maintaining Water Balance Homeostasis • Remember, salt sucks! • Salt water fish have a tendency to lose water. • Fresh water fish have a tendency to gain water • This is why you can’t put a saltwater fish in fresh water- it is not adapted to it.
Maintaining Water BalanceHomeostasis • Kidney maintain homeostasis and water balance.
Fish Reproduction • Most fish fertilize their eggs externally • Spawning- the process of fertilizing eggs (fish reproduction) • Fry- baby fish
Types of Agnathans • Hagfish- ocean scavengers, not much is known of them.
Types of Agnathans • Hagfish- ocean scavengers, not much is known of them. • Lamprey- fresh and salt water, they are parasitic on other fish. Cartilage skeletons and circular (sucker like) mouths.
Types of Cartilage Fish • Sharks • Adapted for predatory lifestyle • Pectoral fins do not move- increases speed and stability (like an airplane). • Cartilage skeletons • Teeth replaced frequently
Types of Cartilage Fish • Sharks • Special scales that feel like sandpaper • No operculum (gill cover), sharks must keep moving to breath • Most have live births
Types of Cartilage Fish • Manta Rays and Sting Rays • Flexible pectoral fins and wide bodies • Most live in shallow water and are fairly docile • Mouth located on the underside, they prey on fish
Types of Bony Fish (Osteichtyes) • Ray-finned • Majority of fish are this type. • Fins are supported by bony structures called rays
Types of Bony Fish (Osteichtyes) • Lobe Finned Fishes • Fins consist of long, muscular lobe supported by a central core of bones • Thought to be ancestors of amphibians • Examples: Coelacanth and Lungfish
Fish Adaptations • Lateral Line System • Used to detect vibrations and orientate fish in the water. • A line of cells running down the side of the fish.
Fish Adaptations • Gill Cover (Operculum) • Cover gills. • Movement of operculum allows more water to be drawn in.
Fish Adaptations • Swim Bladder • A gas filled sac that helps the fish maintain buoyancy. • Sharks do not have swim bladders, they sink when they stop swimming.
Fins • Dorsal fin- balance, staying upright • Caudal fin- forward movement • Pectoral fin- steering • Pelvic fin- steering • Anal fin- balance