1. BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections Chapter 34 Vertebrates

2. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most chordates are vertebrates: have a segmented backbone –Their endoskeletons include a skull –Their backbone is composed of vertebrae VERTEBRATES Figure 18.16 VertebraeBackboneSkull

3. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lampreys lack hinged jaws –They are classified as agnathans 18.17 Most vertebrates have hinged jaws Figure 18.17A, B Jaws evolved by the modification of skeletal supports of the gill slits Gill slits Skeletal rods Skull Mouth

4. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 5 Main Classes of Vertebrates Fish Amphibians Reptiles Birds Mammals

5. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fish are jawed vertebrates with gills and paired fins There are two classes of fish –Chondrichthyes, cartilaginous fishes such as sharks and rays. They have a lateral line system, a sense organ used to detect vibrations. –Osteichthyes, bony fishes such as tuna and trout Fish Figure 18.18A

6. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Bony fishes are more diverse and have –more mobile fins –operculi that move water over the gills –a buoyant swim bladder Figure 18.18B BONY SKELETON SWIM BLADDER Gills OPERCULUM

7. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings There are three major classes of bony fishes –Ray-finned fishes (salmon and trout) –Lobe-finned fishes (coelocanth) –Lungfishes (evolved into humans) Figure 18.18C Rainbow trout, a ray-fin Coelacanth, a lobe-fin

8. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Amphibians were the first land vertebrates Class Amphibia is represented today by –frogs –toads –salamanders 18.19 Amphibians

9. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Their 4 limbs (tetrapods) allow them to move on land –However, amphibian larvae must develop in water (and go through metamorphosis) –Found in damp habitats –Threatened by fungal pathogens, habitat loss, acid rain, and pollution Figure 18.19A-C

10. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Class Reptilia is able to live on land due to –waterproof scales –a shelled, amniotic egg Modern reptiles are ectotherms (cold blooded) –They warm their bodies by absorbing heat from the environment 18.20 Reptiles Figure 18.20A, B

11. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Reptiles Include turtles, alligators, crocodiles, lizards, and snakes

12. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Dinosaurs were the most diverse reptiles to inhabit land –This group included some of the largest land animals ever –They may have been endothermic, producing their own body heat –They evolved into birds and some modern reptiles Figure 18.20C

13. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Like reptiles, class Aves has –scales –amniotic eggs –No bladders –Only one ovary –Light bones –Wings and feathers 18.21 Birds Figure 18.21A Teeth (like reptile) Wing claw (like reptile) Feathers Long tail with many vertebrae (like reptile)

14. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Other bird characteristics include –an endothermic metabolism –hollow bones –a highly efficient circulatory system –A 4 chambered heart Figure 18.21B, C

15. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Class Mammalia descended from reptiles Mammals are endothermic (warm blooded) There are two unique mammalian characteristics –Hair, which insulates the body –Mammary glands, which produce milk that nourishes their young 18.22 Mammals

16. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most mammals give birth to young after a period of embryonic development inside the body of the mother –The embryo is nurtured by an organ called the placenta A few mammals lay eggs-Monotremes Platypus Echidna Figure 18.22A

17. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Marsupials have a short gestation –The tiny offspring complete development inside a pouch –Example: kangaroos, koalas, wombats, Tasmanian devils Figure 18.22B

18. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most mammals are eutherians, also called placentals –They have a relatively long gestation –Complete embryonic development occurs within the mother, in a sac called a placenta Figure 18.22C