1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu REPTILES

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Reptiles Mesozoic = age of Reptiles have a strong, bony skeleton. Most have two pairs of limbs.They have toes with claws Reptiles have an Reptiles have dry, Reptiles have amniotic Dinosaurs = ancient reptiles (extinct million years ago.) Plesiosaur = ancient aquatic reptile, Pterosaur = flying The Reptilian Body

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Reptilian Body

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Reptiles, continued Metabolism (requires little energy) Reptiles’ ectothermic metabolism is too slow to generate enough to warm their bodies, so they must absorb heat from their surroundings. A reptile’s body temperature is largely determined by the At low temperatures, most reptiles become and unable to function. The Reptilian Body

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Reptilian Body

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Retention Unlike amphibians, reptiles can be considered have adaptations that free them from the water requirements of amphibians. The Reptilian Body

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Retention, continued Watertight Skin Reptiles have a skin made of light,. These scales and form a protective, almost watertight skin that minimizes water loss. The Reptilian Body

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water Retention, continued Watertight Eggs A reptile’s amniotic egg provides a moist environment in which the develops. An amniotic egg contains both a water supply and a food supply. Allantois – egg part that exchanges O 2 and CO 2 (it connects to the ) The amniotic egg’s tough shell keeps the egg from drying out. = protective membrane within the egg. The Reptilian Body

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Respiration Because are far more active than amphibians, they have greater metabolic requirements for The Reptilian Body

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Respiration, continued Lungs Unlike the skin of an amphibian, the scaly skin of a reptile does not permit The of most reptiles have many internal folds and sacs (alveoli), greatly increasing their surface area. Reptiles have strong attached to their rib cages. These muscles help to move air into and out of the lungs, increasing the lungs’ efficiency. The Reptilian Body

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Respiration, continued In reptiles, the septum extends into the ventricle, partly dividing it into As a result, is delivered to the body cells more efficiently than in amphibians. Crocodiles have a heart with a completely divided The Reptilian Body

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Reptilian Body

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproduction Reptilian eggs are fertilized within the female, a process called internal Many reptiles are, meaning the young hatch from eggs. Some species of snakes ovoviparous, which means the female retains the eggs within her body until shortly before hatching, or the eggs may hatch within the female’s body. The Reptilian Body

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lizards and Snakes Snakes and lizards belong to the order Squamata (ex. =.) A characteristic of this order is a lower jaw that is to the skull. This enables snakes and many lizards to swallow large prey. Today’s Reptiles

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lizards and Snakes, continued Lizards Most lizards are. Gila monsters are venomous. Most lizards are small, measuring less than cm (1 ft) in length. Some lizards can detach their tails when a predator tries to eat it (.) Today’s Reptiles

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lizards and Snakes, continued Snakes The skeleton of snakes lacks a pectoral girdle, the supporting bones for the bones of the Snakes do not have suited for cutting and chewing. Have Jacobson’s organs to sense heat and locate prey. Some snakes are constrictors, squeezing their prey until it suffocates, then eating it. Other snakes kill their prey with poisonous venom. (an = a venomous snake) Today’s Reptiles

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu External Structure of a Today’s Reptiles

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Internal Structure of a Timber Rattlesnake Today’s Reptiles Do Not Draw inject venom through large fangs.

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Other Orders of The remaining orders of living reptiles contain far fewer species than the order There are about 250 or more species of turtles and tortoises, all classified in the order There are about 25 species of crocodiles in the order There are only two species of tuataras in the order Rhynchocephalia. Even sea turtles return to land to Today’s Reptiles

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Other Orders of Reptiles, continued Turtles and Tortoises The bodies of turtles and tortoises are encased within a hard, bony, protective shell. The is the dorsal (top) part of the shell, and the is the ventral (bottom) portion. Turtles and tortoises lack teeth but have jaws covered by sharp plates, which form Today’s Reptiles

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Today’s Reptiles

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Today’s Reptiles

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Other Orders of Reptiles, continued Crocodiles and Crocodiles and alligators are aggressive is a crocodilia. They capture their prey by stealth, drawing it underwater to be Unlike other living, crocodilians care for their young after Today’s Reptiles

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Other Orders of Reptiles, continued Tuataras are lizardlike reptiles up to (2 ft) long with a spiny crest on the back – how they get their name. The two living species of tuataras are members of the genus and are native to New Zealand. Today’s Reptiles

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu