Modern Fishes and Amphibians: Anatomy, Reproduction, and Adaptations

1. Chapter 33 Fishes and Amphibians Section 1: The Fish Body Section 2: Today’s Fishes Section 3: Amphibians

2. Section 1 The Fish Body Objectives: • Describe the characteristics of modern fishes. • Summarize how fish obtain oxygen. • Summarize how blood circulates through a fish. • Contrast how marine and freshwater fishes balance their salt and water content. • Describe two methods of reproduction in fishes.

3. Section 1 The Fish Body Key Characteristics of Modern Fishes • Features All fishes have gills and a backbone, and they circulate oxygen-rich blood from their gills directly to body tissues.

4. Section 1 The Fish Body Gills • Countercurrent Flow Countercurrent flow maximizes the amount of oxygen that can be extracted from water through the gills.

5. Section 1 The Fish Body Circulation of Blood • Circulation The four-chambered heart collects oxygen-poor blood from the body and pumps it through the gills where it receives oxygen. Oxygen-rich blood then circulates to the rest of the body.

6. Section 1 The Fish Body Kidneys • Salt and Water Balance Fish rely on their gills and a pair of kidneys to regulate its salt and water balance.

7. Section 1 The Fish Body Reproduction • Reproduction Most fishes fertilize their eggs externally as males and females release their gametes near one another in the water.

8. Section 2 Today’s Fishes Objectives: • Distinguish between the three general categories of modern fishes. • Describe the major external and internal characteristics of the yellow perch. • Summarize features of bony fishes.

9. Section 2 Today’s Fishes Jawless Fishes • Hagfishes and Lampreys Hagfishes and lampreys are the only surviving jawless fishes.

10. Section 2 Today’s Fishes Cartilaginous Fishes • Sharks Sharks have light, highly streamlined bodies well suited for rapid swimming, which makes them swift and efficient predators.

11. Section 2 Today’s Fishes Bony Fishes • Features Bony fishes have an internal skeleton made completely of bone, a swim bladder, a lateral limb sensory system, and a set of gill covers called opercula. • Ray-Finned Bony Fishes Ray-finned bony fishes comprise the vast majority of living fishes. • Lobe-Finned Bony Fishes Only seven species of lobe-finned fishes survive today.

12. Section 3 Amphibians Objectives: • Summarize the characteristics of modern amphibians. • Compare the three orders of living amphibians. • Describe the major external and internal characteristics of the leopard frog.

13. Section 3 Amphibians Key Characteristics of Modern Amphibians • Features Most amphibians have legs, breathe with lungs and through their skin, and have two circulatory loops. • Lungs An amphibian lung is basically an air sac with a large surface area for gas exchange. • Double-Loop Circulation The amphibian heart pumps oxygen-poor blood to the lungs and receives oxygen-rich blood from the lungs. The oxygen-rich blood is then pumped to the body.

14. Section 3 Amphibians Frogs and Toads • Reproduction in Frogs Frogs release their eggs into water.

15. Section 3 Amphibians Salamanders and Caecilians • Salamanders Salamanders are semiaquatic predators with tails. • Caecilians Caecilians are legless amphibians specialized for burrowing.