 Learning Goal Name the main characteristics of fishes Name the major groups of fishes and describe how they differ  Warm up: What does the backbone surround and protect in a vertebrate? Homework: Finish pages 5-8

Chapter 11 Section 2

 Vertebrate  Lives in the water  Uses fins to move  Ectotherms  Obtain oxygen through gills  Have scales

 Fishes get oxygen from the water Fish gulps water (water contains oxygen) Moves through openings in fish’s throat to the gills Water flows over gills Oxygen moves from water into the fish’s blood Carbon dioxide comes out through gill covers (operculae)

 Closed circulatory system  Heart has two chambers, or inner spaces Pumps blood in one loop  Heart to the gills  Gills to rest of the body  Back to heart

 Fins help fish swim  Thin membrane stretched across bony supports, rays  Fin provides large surface to push against the water (canoe paddle)  Movement is related to obtaining food and reproduction

 External fertilization: the eggs are fertilized outside the female’s body  Male hovers close to female and spreads a cloud of sperm cells over the eggs  Internal fertilization: giving birth to live young Sharks Guppies

 Nervous system and sense organs of fishes help them find food and avoid predators  Keen sense of touch, smell, and taste help fishes capture food

 Jawless  Cartilaginous  Bony

 No jaws or scales  Have mouths instead (scraping, stabbing, and sucking their food)  Cartilage: tissue that is more flexible than bone  Examples Hagfish  Look like large, slimy worms Lampreys  Can be parasites  Use sharp teeth and suction cup mouths to feed on other fishes  Eel-shaped bodies

 Have jaws and scales, and skeletons made of cartilage  Most sharks cannot pump water over their gills, rely on swimming or currents to keep water moving across gills  Rays and skate take in water through small holes located behind their eyes  Usually carnivores Sharks: attack and eat nearly anything that smells like food, many rows of teeth Rays and skates: hunt on ocean floor, crushing mollusks, crustaceans, and small fishes with their teeth

 Examples: trout, tuna, goldfish  Have jaws, scales, a pocket on each side of the head that holds the gills, and a skeleton made of hard bones  Fins: help the fish stay upright  Scales: cover the body by overlapping each other  Gill Pocket: holds the gills  Swim Bladder: helps stabilize the fish at different depths in the water