1. Fishes Chapter 11 Section 2

2. Characteristics of Fishes  Vertebrate  Lives in the water  Uses fins to move  Ectotherms  Obtain oxygen through gills  Have scales

3. Obtaining Oxygen  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

4. Circulatory System  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

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

6. 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

7. Nervous System  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

8. Major Groups of Fishes  Jawless  Cartilaginous  Bony

9. Jawless Fishes  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

10. Cartilaginous Fishes  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

11. Bony Fishes  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

13. Diversity of Bony Fishes