Chapter 3

1. Chapter 3

2. Phylum Chordata At some point of their lives, all have a: - notochord - hollow nerve cord - pharyngeal pouches - tail

3. Three groups of Chordates • Lancelets • Tunicates • Vertebrates – largest group – has a backbone No backbone

5. Vertebrates • Backbone or vertebral column - Protects spine - Support • Endoskeleton -Support -Shape -grows with the organism

6. Groups of Chordates • Eight Groups - Six are ectotherms -Rely on environment for heat - “cold blooded” - Two are endotherms - Maintain their body heat - “warm blooded”

7. FISH • Evolved 540 mya • Ectotherms • Water dwelling vertebrates • Scales (most) • Fins • Gills • Most do external fertilization

8. Jawless Fish • Most primitive • No scales, fins, bones or jaw • Has skeleton made of cartilage • Examples- hagfish and lamprey

9. Cartilaginous Fish • Skeleton made of cartilage • Tooth-like scales • No swim bladder • Sharks, skates, and rays

10. Bony Fish • Have a swim bladder -Gives the ability to float or sink • Color vision • Lateral line that senses movement

11. AMPHIBIANS • Evolved 350 mya • Ectotherms • Lungs • Breathe through skin • Term amphibian means “double life” • Live on land and water – soft eggs • Goes through metamorphosis • Ecological indicators

12. Caecilians • Legless amphibian • Lives in damp soil in the tropics • Eats small invertebrates • Thin moist skin • Small eyes under skin but are blind

13. Salamander • 390 known species • Eats small vertebrates • Long tail and four small legs

14. How Frogs and Toads are Alike • 90% of all amphibians are frogs and toads • Found all over the world • Highly adapted for life on land • Sticky tongues that are attached to the front of the mouth instead of the back • Strong legs for jumping • Ears • Vocal cords

15. How Frogs and Toads are Different frogs toads Bumpy skin Dry skin Lay eggs in strings • Smooth skin • Moist skin • Lay eggs in bunches

16. Frog Life Cycle

17. REPTILES • Thick, dry, water tight skin • Ectotherms • Lungs to breathe • Evolved 300 mya • Strong vertical legs • Most lay thick rubbery eggs. This allows them to reproduce on land • Internal fertilization

18. Reptile eggs • Shell - protects the egg • Albumen – provides water and protein • Amniotic sac - protects embryo • Yolk - provides food • Allantois – stores waste and passes oxygen

20. ter

21. Lizards • About 4,000 species • Live in deserts, jungle, forests and grasslands • Most eat small invertebrates and plants but some are strictly herbivores • The tail of some lizards separate from the body when the lizard is grabbed. The tail that is left behind wriggles, confusing the other animal.

23. Turtles and Tortoises • 250 species • Slow and inflexible • Protective shell • Tortoises live on land and have bumpy shell • Turtles live on land and have smooth shells

25. Snakes • About 1600 species • No legs • Scales on belly pull snake forward • Carnivores with a good sense of smell

26. Alligators and Crocodiles • Eyes and nose on top of head so they can hide under water • Alligators have a rounded snout, crocodiles have a narrow snout

27. Alligators and Crocodiles